AP Biology

maximum parsimony

"Occam's Razor." A principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that is consistent with the facts.

homeostasis

"Steady state" or "constant internal milieu".

pyramid of energy

90% of all energy is lost between trophic levels.

nuclease

A DNA cutting enzyme that excises damaged DNA.

recombinant DNA

A DNA molecule made in vitro with segments from different sources.

enhancer

A DNA segment containing multiple control elements that can recognize certain transcription factors that stimulate the transcription of nearby genes.

replication fork

A Y-shaped region on a replicating DNA molecule where new strands are growing.

R plasmid

A bacterial plasmid carrying genes that confer resistance to certain antibiotics.

signal

A behavior that causes change in another's behavior.

innate behavior

A behavior that is developmentally fixed.

parasympathetic division

A branch of the autonomic nervous system that maintains normal body functions; it calms the body ever conserves energy.

synaptic terminal

A bulb at the end of an axon in which neurotransmitter molecules are stored and released.

fruit ripening

A burst of ethylene production in a fruit triggers the ripening process.

Carbohydrate side chains

A carbohydrate side chain is attached to the surface of some proteins found only on the outer surface of the plasma membrane.

enzyme

A catalytic protein.

lysosome

A cell organelle that contains digestive enzymes.

Cell wall

A cell wall is a rigid layer just outside of the plasma membrane that provides support for the cell. It is found in plants, protists, bacteria, (made out of cellulose), and fungi (made out of chitin).

turgid

A cell with a cell wall that has a reasonable amount of pressure but is healthy.

transformation

A change in genotype and phenotype due to the assimilation of external DNA by a cell.

deletion

A change to a chromosome in which a fragment of the chromosome is removed.

cytogenetic maps

A chart of a chromosome that locates genes with respect to chromosomal features distinguishable in a microscope.

catalyst

A chemical agent that speeds up a reaction without being consumed by the reaction.

Compound

A chemical compound is formed when two or more different types of atoms are combined in a fixed ration.

Chemical reaction

A chemical reaction describes a chemical change in which reactants react to form products chemically different from the reactants.

trisomic

A chromosomal condition in which a particular cell has an extra copy of one chromosome, instead of the normal two.

monosomic

A chromosomal condition in which a particular cell has only one copy of a chromosome, instead of the normal two.

blue-light photoreceptors

A class of light receptors in plants. Blue light initiates a variety of responses, such as phototropism and slowing of hypocotyl elongation.

phytochromes

A class of light receptors in plants. Mostly absorbing red light, these photoreceptors regulate many plant responses, including seed germination and shade avoidance.

cytokinins

A class of plant hormones that retard aging and act in concert with auxin to stimulate cell division, influence the pathway of differentiation, and control apical dominance.

gibberellins

A class of related plant hormones that stimulate growth in the stem and leaves, trigger the germination of seeds and breaking of bud dormancy, and stimulate fruit development.

taxonomy

A classification of organisms into groups based on similarities.

expression vector

A cloning vector that contains the requisite prokaryotic promoter just upstream of a restriction site where a eukaryotic gene can be inserted.

yeast artificial chromosome (YAC)

A cloning vector that has telomeres and a centromere that can accommodate large DNA inserts and uses the eukaryote yeast as a host cell.

ganglion

A cluster of nerve cell bodies, often of similar function, located in the PNS.

photosystem

A cluster of pigments embedded into a thylakoid membrane.

cyclic AMP (cAMP)

A compound formed from ATP that acts as a second messenger.

dormancy

A condition typified by extremely low metabolic rate and a suspension of growth and development.

Downs Syndrome

A congenital disorder caused by having an extra Chromosome 21.

Covalent bond

A covalent bond is formed when electrons are shared between atoms and can be polar or non-polar.

MPF

A cyclin-Cdk complex that causes the cell to move from interphase into mitosis.

systemic acquired resistance (SAR)

A defensive response in infected plants that helps protect healthy tissue from pathogenic invasion.

restriction enzyme

A degradative enzyme that recognizes and cuts up DNA (including that of certain phages) that is foreign to a bacterium.

barr body

A dense body formed from a deactivated X chromosome.

nucleoid

A dense region of DNA in a prokaryotic cell.

Punnett square

A diagram for predicting the allele composition of offspring from a cross between individuals of known genetic makeup.

pedigree

A diagram that shows the occurrence of a genetic trait in several generations of a family.

concentration gradient

A difference in the concentration of a substance across a distance.

lagging strand

A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork.

cell plate

A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.

Fixed action pattern

A fixed action pattern is a particular type of innate behavior that is not a simple reflex, but no a conscious decision. An example is the egg-rolling behavior exhibited by the graylag goose. If the egg is removed form the goose, it will continue to make the same movement.

thylakoids

A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy

incomplete flower

A flower in which one or more of the four basic floral organs such as sepals, petals, stamens, or carpels are either absent or nonfunctional.

complete flower

A flower that has all four basic floral organs: sepals, petals, stamens, and carpels.

florigen

A flowering signal, not yet chemically identified, that may be a hormone or may be a change in relative concentrations of multiple hormones.

active immunity

A form of acquired immunity in which the body produces its own antibodies against disease-causing antigens.

binary fission

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size.

simple fruit

A fruit derived from a single carpel or several fused carpels.

aggregate fruit

A fruit derived from a single flower that has more than one carpel.

multiple fruit

A fruit derived from an entire inflorescence.

Functional group

A functional group is a distinctive group of atoms that play a large role in determining the chemical behavior of the compound they are a part of. In amino acids, functional groups include the carboxyl group and the amino group.

regulatory gene

A gene that codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.

cystic fibrosis

A genetic disorder that is present at birth and affects both the respiratory and digestive systems.

episome

A genetic element that can exist either as a plasmid or as part of the bacterial chromosome.

linkage map

A genetic map based on recombination frequencies.

linkage map

A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes.

physical map

A genetic map in which the actual physical distances between genes or other genetic markers are expressed, usually as the number of base pairs along the DNA.

proteasomes

A giant protein complex that recognizes and destroys proteins tagged for elimination by the small protein ubiquitin.

Glycosidic bond

A glycosidic bond is a covalent bond in which a carbohydrate binds to another group, which could also be a carbohydrate. A glycosidic bond is found between the two glucose molecules in maltose.

cline

A graded change in a trait along a geographic axis.

absorption spectrum

A graph plotting a pigment light light absorption.

complement system

A group of about 30 blood proteins that may amplify the inflammatory response, enhance phagocytosis, or directly lyse extracellular pathogens.

inflorescence

A group of flowers tightly clustered together.

cohort

A group of individuals of the same age.

tropism

A growth response that results in the curvature of whole plant organs toward or away from stimuli owing to differential rates of cell elongation.

gametes

A haploid cell such as an egg or sperm that unite during sexual reproduction to produce a diploid zygote.

vaccine

A harmless variant or derivative of a pathogen that stimulates a host's immune system to mount defenses against the pathogen.

character

A heritable feature that varies among individuals.

Tay-Sachs disease

A human genetic disease caused by a recessive allele that leads to the accumulation of certain lipids in the brain. Seizures, blindness, and degeneration of motor and mental performance usually become manifest a few months after birth.

Duchenne muscular dystrophy

A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue.

Southern blotting

A hybridization technique that enables researchers to determine the presence of certain nucleotide sequences in a sample of DNA.

Hydrophilic

A hydrophilic molecule is a molecule that mixes with water because it is polar, such as a phosphate head in a lipid.

Hydrophobic

A hydrophobic molecule is a molecule that does not mix with water because it is non polar, such as a fatty acids.

fate maps

A labor-intensive study to produce useful territorial diargams of embryonic development.

myelin sheath

A layer of electrical insulation that surrounds the axon.

cDNA library

A limited gene library using complementary DNA. The library includes only the genes that were transcribed in the cells examined.

sensitive period

A limited phase in an animal's development that is the only time when certain behaviors can be learned.

DNA ligase

A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end of a growing chain.

Lipid

A lipid is an organic molecule consisting of carbon, hydrogen, and oxygen atoms and includes fats, oils, phospholipids, and steroids. Lipids are important because they function as structural components of cell membranes, sources of insulation, and a means of energy storage.

habituation

A loss of responsiveness to stimuli that convey little or no information.

Lymph node

A lymph node is a mass of tissue found along the course of a lymph vessel that contains a large number of lymphocytes, white blood cells that attack foreign pathogens.

fruit

A mature ovary of a flower that protects dormant seeds and often aids in their dispersal.

entropy

A measure of disorder or randomness.

map units

A measurement of the distance between genes; one map unit is equivalent to a 1 percent recombination frequency.

double fertilization

A mechanism of fertilization in angiosperms, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm.

aquaporin

A membrane protein, specifically a transport protein, that facilitates the passage of water through channel proteins.

channel protein

A membrane protein, specifically a transport protein, that has a hydrophilic channel that certain molecules or atomic ions use as a tunnel.

transport protein

A membrane protein, specifically a transport protein, that has a hydrophilic channel that certain molecules or atomic ions use as a tunnel.

carrier protein

A membrane protein, specifically a transport protein, that holds onto molecules and changes their shapes in a way that shuttles them across the membrane.

viral envelope

A membrane that cloaks the capsid that in turn encloses a viral genome.

contractile vacuoles

A membranous sac that helps move excess water out of the cell.

feedback inhibition

A metabolic pathway is switched off by the inhibitory binding of its end product to an enzyme that acts early in the pathway.

peroxisome

A microbody containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide.

punctuated equilibrium

A model of evolution in which a new species will change the most as it buds from a parent species, and then will change little for the rest of its existence.

gradualism

A model of evolution in which gradual change over a long period of time leads to biological diversity.

sepal

A modified leaf in angiosperms that helps enclose and protect a flower bud before it opens.

petal

A modified leaf of a flowering plant; petals are the often colorful parts of a flower that advertise it to insects and other pollinators.

Polar

A molecule is polar if it has partially positive and partially negative charged ends, such as water.

elicitors

A molecule that induces a broad type of host defense response

paraphyletic group

A monophyletic group in which some descendants of the common ancestor have been removed.

nonsense mutations

A mutation that changes an amino acid codon to one of three stop codons, resulting in a shorter and usually nonfunctional protein.

nuclear lamina

A netlike array of protein filaments lining the inner surface of the nuclear envelope; it helps maintain the shape of the nucleus.

rough ER

A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm; covered with ribosomes that make membrane proteins and secretory proteins.

endomembrane system

A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

action potential

A neural impulse; a brief electrical charge that travels down an axon.

Neurotransmitter

A neurotransmitter is a chemical released by an axon into the space between the two neuron, called the synapse. The neurotransmitter diffuses across the synaptic cleft and binds to receptors on the dendrites of the next neuron, usually triggering an action potential.

serotonin

A neurotransmitter that affects hunger,sleep, arousal, and mood.

Fats

A neutral fat is the simplest lipid and consists of three fatty acids and one molecule of glycerol, also known as a triglyceride.

Non-polar covalent

A non-polar covalent bond is a covalent bond in which the electrons are shared equally between the atoms.

tetrad

A pair of chromosomes form tetrads made up of four chromatids.

fermentation

A partial degradation of sugars that occur without the use of oxygen.

Pathogen

A pathogen is a disease-causing agent that activates an immune response in the body.

Peptide bond

A peptide bond is the bond between two amino acids.

prophage

A phage genome that has been inserted into a specific site on the bacterial chromosome.

lysogenic cycle

A phage replication cycle in which the viral genome becomes incorporated into the bacterial host chromosome as a prophage and does not kill the host.

temperate phage

A phage that is capable of reproducing by either the lytic or lysogenic cycle.

Phagocytes

A phagocyte is a type of cell that is part of the body's defense mechanism. They are cells that are capable of engulfing and eventually destroying antigens.

cladistics

A phylogenetic classification system that uses shared derived characters and ancestry as the sole criterion for grouping taxa.

circadian rhythm

A physiological cycle of about 24 hours that is present in all eukaryotic organisms and that persists even in the absence of external cues.

photoperiodism

A physiological response to photoperiod, the relative lengths of night and day. An example of photoperiodism is flowering.

F factor

A piece of DNA that confers the ability form a sex pili.

triple response

A plant growth maneuver in response to mechanical stress, involving slowing of stem elongation, a thickening of the stem, and a curvature that causes the stem to start growing horizontally.

salicylic acid

A plant hormone that may be partially responsible for activating systemic acquired resistance to pathogens.

abscisic acid (ABA)

A plant hormone that slows down growth, promotes seed dormancy and facilitates drought tolerance.

long-day plant

A plant that flowers only when the light period is longer than a critical length. Usually spring or early summer.

short-day plant

A plant that flowers only when the light period is shorter than a critical length. Usually fall or winter.

day-neutral plant

A plant whose flowering is not affected by photoperiod.

hypersensitive response (HR)

A plant's localized defense response to a pathogen

G-protein-linked receptor

A plasma membrane receptor that works with the help of a G-protein.

active site

A pocket or groove on the surface of the enzyme.

restriction point

A point of no return in the cell cycle; once this point passes, a cell is committed to a full round of the cell cycle.

Polar covalent

A polar covalent bond is a covalent bond in which the electrons are shared unequally - one atom attracts electrons more than the other.

Polymer

A polymer is a molecule with repeating subunits of the same general type, such as polysaccharides.

Polyunsaturated

A polyunsaturated fatty acid has many double bonds within the fatty acids.

natural selection

A population can change over time if individuals with more fit traits leave more offspring than less fit individuals.

norepinephrine

A precursor of epinephrine that is secreted by the adrenal medulla and also released at synapses.

maximum likelihood

A principle that states that when considering multiple phylogenetic hypotheses, one should take into account the one that reflects the most likely sequence of evolutionary events, given certain rules about how DNA changes over time.

catabolic

A process in which large molecules are broken down

action spectrum

A profile of the relative performance of the different wavelengths in photosynthesis.

TATA box

A promoter DNA sequence crucial in forming the transcription initiation complex.

selective permeability

A property of a plasma membrane that allows some substances to cross more easily than others.

enzymatic activity

A protein built into the membrane with active site exposed.

gated channel

A protein channel in a cell membrane that opens or closes in response to a particular stimulus.

PR protein

A protein involved in plant responses to pathogens (PR = pathogenesis-related).

Protein

A protein is a polypeptide, a chain of amino acids, that twists and folds on itself.

activator

A protein that binds to DNA and stimulates transcription of a specific gene.

repressor

A protein that suppresses the transcription of a gene.

glycoprotein

A protein with one or more carbohydrates covalently attached to it.

signal-recognition particle

A protein-RNA complex that recognizes a signal peptide as it emerges from the ribosome.

receptor tyrosine kinase

A receptor with enzymatic activity that can trigger more than one signal transduction pathway at once, helping the cell regulate and coordinate many aspects of cell growth and reproduction.

reducing agent

A reduces B, which accepts the donated electrons.

mark-recapture method

A sampling technique used to estimate wildlife populations.

diacylglycerol (DAG)

A second messenger produced by the cleavage of a certain kind of phospholipid in the plasma membrane.

transposable genetic element

A segment of DNA that can move within the genome of a cell by means of a DNA or RNA intermediate; also called a transposable element.

fixed action patterns (FAP)

A sequence of unlearned behavioral acts that is unchangeable and usually carried to completion.

signal transduction

A series of molecular changes that converts a signal on a target cell's surface to a specific response inside the cell.

genomic library

A set of thousands of DNA segments from a genome, each carried by a plasmid, phage, or other cloning vector.

anaphylactic shock

A severe reaction that occurs when an allergen is introduced to the bloodstream of an allergic individual. Characterized by bronchoconstriction, labored breathing, widespread vasodilation, circulatory shock, and sometimes sudden death.

ZW system

A sex determination system in fish, butterflies, birds where males are ZZ and Females are ZW. The egg determines the sex of the offspring.

haplo diploid system

A sex determination system in most species of bees and ants in which there are no sex chromosomes. Females develop from fertilized eggs (diploid) and males develop from unfertilized eggs (haploid).

XO system

A sex determination system in some insects in which O stands for the absence of a sex chromosome. Females are XX, Males are XO. Males produce two classes of sperm: X sperm and sperm with no chromosome. The sperm determines the sex of the offspring.

XY system

A sex determination system in which females have two of the same kind of sex chromosome and males have two different ones.

kinesis

A simple change in activity or turning rate in response to a stimuli.

pistil

A single carpel or a group of fused carpels in a flower.

sticky end

A single-stranded end of a double-stranded DNA restriction fragment.

plasmid

A small ring of DNA that carries accessory genes separate from those of a bacterial chromosome; also found in some eukaryotes, such as yeast.

Solutes

A solute is a substance that is dissolved in a solvent.

Acidic

A solution is acidic if it contains excess hydrogen ions. It will have a pH less than 7.

Basic

A solution is basic if it releases hydroxide ions when added to water. These solutions are said to be alkaline and are usually slippery.

Neutral

A solution is neutral, neither basic nor acidic, if it has a pH of 7.

kinetochore

A specialized region on the centromere that links each sister chromatid to the mitotic spindle.

Species

A species is a group of organisms having many physical and behavior characteristics in common and are able to interbreed to produce fertile and viable offspring.

promoter

A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing mRNA.

restriction site

A specific sequence on a DNA strand that is recognized as a cut siteby a restriction enzyme.

inducer

A specific small molecule that inactivates the repressor in an operon.

signal peptide

A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell.

centrosome

A structure in animal cells containing centrioles from which the spindle fibers develop.

ovule

A structure that develops within the ovary of a seed plant and contains the female gametophyte.

culture

A system of information transfer through influential social learning or teaching.

polyphyletic group

A taxonomic grouping consisting of several species that lack a common ancestor (more work is needed to uncover species that tie them together into a monophyletic clade).

monophyletic group

A taxonomic grouping that includes an ancestral species and all of its descendants.

clade

A taxonomic grouping that includes only a single ancestor and all of its descendants.

polymerase chain reaction (PCR)

A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides.

nuclear transplantation

A technique in which the nucleus of one cell is placed into another cell that already has a nucleus or in which the nucleus has been previously destroyed.

electroporation

A technique to introduce recombinant DNA into cells by applying a brief electrical pulse to a solution containing the cells. The pulse creates temporary holes in the cells' plasma membrane, through which DNA can enter.

virulent

A term describing a pathogen against which a plant has little specific defense.

avirulent

A term describing a pathogen that can only mildly harm, but not kill, the host plant.

endospore

A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions.

chromosomes

A threadlike, gene-carrying structure found in the nucleus. Consists of one very long DNA molecule and associated proteins.

seed coat

A tough outer covering of a seed, formed from the outer coat of an ovule.

electrogenic pump

A transport protein that generates voltage across a membrane, causing a net separation in charge.

transposon

A transposable genetic element that moves within a genome by means of a DNA intermediate.

pollen tube

A tube that forms after germination of the pollen grain and that functions in the delivery of sperm to the ovule.

oligosaccharins

A type of elicitor that is derived from cellulose fragments released by cell wall damage

pinocytosis

A type of endocytosis in which the cell "gulps" droplets of fluid into tiny vesicles.

receptor-mediated

A type of endocytosis in which the cell acquires bulk quantities of specific substances, even though they may not be very concentrated in the extracellular fluid.

scaffolding proteins

A type of large relay protein to which several other relay proteins are simultaneously attached to increase the efficiency of signal transduction.

inversion

A type of mutation in which the order of the genes in a section of a chromosome is reversed.

amoeba

A type of protist characterized by great flexibility and the presence of pseudopodia

positive feedback

A type of regulation that responds to a change in conditions by initiating responses that will amplify the change. Takes organism away from a steady state.

negative feedback

A type of regulation that responds to a change in conditions by initiating responses that will counteract the change. Maintains a steady state.

lytic cycle

A type of viral (phage) replication cycle resulting in the release of new phages by lysis (and death) of the host cell.

operon

A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes with related functions.

bacteriophage

A virus that infects bacteria; also called a phage.

bacteriophages

A virus that infects bacteria; also called a phage.

gene-for-gene recognition

A widespread form of plant disease resistance involving recognition of pathogen-derived molecules by the protein products of specific plant disease resistance genes.

excretory system hormones

ADH and aldosterone

posterior pituitary hormones

ADH and oxytocin

AIDS

AIDS, or acquired immunodeficiency syndrome, is a devastating disease that interferes with the body's immune system. AIDS is caused by the infection of helper T cells by HIV, which destroys the T cells and prevents the body from defending itself.

pluripotent

Able to give rise to multiple, but not all, cell types.

aneuploidy

Abnormal number of chromosomes.

oxidizing agent

Accepts electrons and becomes reduced.

carotenoids

Accessory pigments that broaden the spectrum of colors that can drive photosynthesis.

chromosome theory of inheritance

According to this theory, genes are carried from parents to their offspring on chromosomes.

Acetylecholine

Acetylcholine is an important neurotransmitter that is released from the end of an axon when calcium ions move into the terminal end of the axon. Acetylcholine is picked up almost instantly by the dendrites of the the next neuron. It can stimulate muscles to contract or inhibit postsynaptic potential. Acetylcholine is released between neurons in the parasympathetic system.

Acetylcholinesterase

Acetylcholinesterase is an enzyme that breaks down extra acetylcholine in the synaptic cleft.

Action potential

Action potential is a change in the membrane potential that produces a nerve impulse. Action potential is an all-or-none response; it doesn't fire "part way," and generally must reach -55mV to produce a response.

helper T cells

Activate macrophages, B cells and T cells.

Activation energy

Activation energy is the energy needed to begin a chemical reaction.

Active transport

Active transport is the movement of a substance against the concentration gradient, which required energy.

proximate questions

Address environmental stimuli, genetic, physiological, and anatomical causes of a behavior.

ultimate questions

Address evolutionary significance of a behavior.

Adenosine triphosphate

Adenosine triphosphate, or ATP, is the energy molecule used by the cell, synthesized in the mitochondria.

Adhesion proteins

Adhesion proteins are membrane proteins that form junctions between adjacent cells.

Adhesion

Adhesion refers to the tendency of water molecules to stick to other substances, which accounts for the phenomenon of capillary action.

acclimatization

Adjusting to a new range of environmental temperatures.

Adrenocorticotropic hormone (ACTH)

Adrenocorticotropic hormone is a hormone produced in the anterior pituitary that stimulates the adrenal cortex to secrete glucocorticoids and mineralocorticoids.

Morula

After a number of cell divisions, the fertilized egg (zygote) becomes a solid ball of cells called a morula.

Sodium-potassium pump

After a part of the neuron has been repolarized, the charges are in their original state, but the ions are on the wrong side of the axonal membrane, with potassium outside and sodium inside. The neuron reestablishes the order of the ions with the sodium-potassium pump, which pumps two potassium ions inside the axon for every three sodium ions it pumps out.

Fetus

After an embryo matures to about 4 weeks, it is referred to as a fetus.

F2 Generation

After the self-pollenization of the F1 generation, this is produced.

life tables

Age-specific summaries of survival patterns of a population.

reproductive table (fertility schedule)

Age-specific summary of reproductive rates in a population.

protobionts

Aggregates of abiotically produced molecules surrounded by a membrane.

leaf abscission

Aging and dropping of leaves controlled by auxin and ethylene.

genomic equivalence

All cells in an organism contain the same complement of genes. These are the same set of genes that are established in the fertilized egg.

life cycle

All of the events in the growth and development of an organism until the organism reaches sexual maturity.

community

All species that inhabit an area.

gene pool

All the genes in a given population at a given time.

biotic factors

All the plant and animal life of a particular region.

Allopatric speciation

Allopatric speciation refers to speciation when part of a population is physically separated from the rest by a geographic barrier and therefore they cannot interbreed.

Allosteric activator

Allosteric activators bind to an enzyme and induce its active form.

Allosteric inhibitor

Allosteric inhibitors bind to an allosteric site and keep the enzyme in its inactive form.

Allosteric regulators

Allosteric regulators are substances that can either inhibit or activate enzymes and that bind at the allosteric site.

Amino acids

Amino acids are organic molecules that serve as the building blocks of proteins. They contain carbon, hydrogen, oxygen, and nitrogen atoms. Every amino acid has four parts: an amino group, a carboxyl group, a hydrogen, and an R group.

macrophages

Amoeboid cells that roam connective tissue and engulf foreign particles and debris of dead cells.

secondary production

Amount of chemical energy in consumers' food that is converted to new biomass.

metabolic rate

Amount of energy an animal uses in a unit of time; the sum of all the energy-requiring biochemical reactions.

primary production

Amount of light energy converted to chemical energy by autotrophs.

gross primary production (GPP)

Amount of light energy that is converted to chemical energy by photosynthesis.

R group

An R-group is any group in which the carbon or hydrogen is attached to the rest of the molecule.

retrovirus

An RNA virus that reproduces by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; an important class of cancer-causing viruses.

hemophilia

An X-linked recessive disorder in which blood fails to clot properly, leading to excessive bleeding if injured.

evolutionary adaptation

An accumulation of inherited characteristics that enhance organisms' ability to survive and reproduce in specific environments.

Adaptation

An adaptation is a trait that improved an individuals fitness, and is favored by natural selection. These adaptions are likely to be passed on to the next generation.

polygenic inheritance

An additive effect of two or more genes on a single phenotypic character.

recessive allele

An allele that is masked when a dominant allele is present

dominant allele

An allele whose trait always shows up in the organism when the allele is present.

Allosteric sites

An allosteric site is a region of the enzyme other than the active site to which a substance can bind, and can regulate enzymatic activity.

Amino group

An amino group is a functional group and is found in organic compounds known as amines.

Amphipathic

An amphipathic molecule has both a hydrophilic region and a hydrophobic region, such as a phospholipid.

conformer

An animal that allows its internal condition to vary with certain external changes.

regulator

An animal that uses internal control mechanisms to moderate internal change in the face of external fluctuation.

Antigen

An antigen is a substance that causes an immune system to produce antibodies against it. These include foreign molecules such as viruses, bacteria, or chemicals.

classical conditioning

An arbitrary stimulus is associated with an award or punishment.

potential range

An area where an organism could potentially survive and reproduce.

bacterial artificial chromosome (BAC)

An artificial version of a bacterial chromosome that can carry inserts of 100, 000 to 500, 000 base pairs.

mitotic spindle

An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.

Atom

An atom is the smallest unit of an element that retains its characteristic properties; they are the building blocks of the physical world.

proton pump

An electrogenic pump that works largely with H+ ions.

Embryo

An embryo is an organism in the early stages of development, and is used to describe an unborn baby up until the 8th week, at which point it is referred to as a fetus. Immediately after fertilization, the zygote undergoes rapid division and becomes a recognizable embryo at around 4 weeks.

radicle

An embryonic root of a plant.

reverse transcriptase

An enzyme encoded by some certain viruses (retroviruses) that uses RNA as a template for DNA synthesis.

DNA polymerase

An enzyme that catalyzes the formation of the DNA molecule.

telomerase

An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells.

primase

An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template.

helicase

An enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands.

Enzyme-substrate complex

An enzyme-substrate complex is the term for the enzyme and substrate(s) bound together.

disturbance

An event, such as storm, fire, flood, drought, overgrazing or human activity, that changes a community and alters resource availability.

transport

An exchange of molecules (and their kinetic energy and momentum) across the boundary between adjacent layers of a fluid or across cell membranes.

clone

An identical genetically individual of the parent

jasmonic acid

An important molecule in plant defense against herbivores.

polygamous

An individual of one sex mating with several of the other.

GABA

An inhibitory neurotransmitter in the brain.

biological clock

An innate mechanism in living organisms that controls the periodicity of many physiological functions.

cognitive maps

An internal representation of the spatial relationships between objects in an animal's surroundings.

Human Genome Project

An international collaborative effort to map and sequence the DNA of the entire human genome.

Ions

An ion is a charged form of an atom.

Ionic bond

An ionic bond is formed between two atoms when one or more electrons are transferred from one atom to the other. In this case, one atom becomes negatively charged and one atom becomes positively charged.

genetic map

An ordered list of the genetic loci along a particular chromosome.

homozygous

An organism having a pair of identical alleles for a character, either dominant or recessive.

genotype

An organism's genetic makeup.

phenotype

An organism's traits.

Analogous structures

Analogous structures are animal features that have the same function but are structurally different, such as a bat's wing and an insect's wing. These strucutres evolved independently of one another.

homoplasies

Analogous structures that have evolved independently.

systematics

Analytical approach to understanding the diversity and relationships of present and past organisms.

analogy

Anatomical similarity due to convergent evolution.

endosymbiotic theory

Ancestors of mitochondria and plastids was prokaryotes thatcame to live in a host cell.

endothermic

Animals that are warmed mostly by heat generated by metabolism.

exothermic

Animals that gain heat mostly from external sources.

actual evapotranspiration

Annual amount of water transpired by plants and evaporated from landscape.

Antidiuretic hormone (vasopressin)

Antidiuretic hormone is a hormone secreted by the posterior pituitary that regulates water intake by nephrons in the kidney. This hormone is made in the hypothalamus, but stored in the posterior pituitary.

T cell receptor

Antigen receptors on a T cell. Unlike antibodies, T cell receptors are never produced in a secreted form.

antigen

Any foreign molecule that is specifically recognized by lymphocytes and elicits an immune response.

cancer

Any malignant growth or tumor caused by abnormal and uncontrolled cell division.

ligand

Any molecule that bonds specifically to a receptor site of another molecule.

somatic cell

Any of the cells of a plant or animal except the reproductive cells.

Apoptosis

Apoptosis, or programmed cell death, plays a crucial role in normal differentiation and development. For example, in a human embryo, apoptosis allows for the removal of tissue between newly developing fingers and toes.

restoration ecology

Applies ecological principles in an effort to return degraded ecosystems to conditions as similar as possible to their natural state.

extremophiles

Archaea that live in extreme environments.

methanogens

Archaea that release methane, a greenhouse gas.

thermophiles

Archaea that thrive in very hot environments, such as volcanic springs.

six kingdom system

Archaebacteria -> Eubacteria -> Protista -> Planae -> Fungi -> Animalia

vestigial structures

Are little or no importance to organism, but remain from an ancestor.

actual range

Area an organism actually occupies.

Blastula

As the cells in the morula continue to divide, they press against each other and produce a fluid filled cavity called a blastocoel.

Depolarization

At the point where the axon connects to the cell body, gated sodium ion channels open up and allow sodium ions to rush into the cell, making the inside of the cell more positive than the outside, a change known as depolarization.

Isotopes

Atoms that have the same number of protons but differ in the number of neutrons in the nucleus are called isotopes.

tendons

Attach muscles to bones.

electronegativity

Attraction of an atom for electrons in a covalent bond.

taxis

Automatic, oriented movement toward or away from some stimuli.

producer

Autotroph.

Autotrophs

Autotrophs, or producers, are organism that are able to make their own food using solar or chemical energy.

per capita offspring

Average number of offspring produced per individual during a specified period of time.

oxidizing agent

B oxidizes A by removing A's electrons.

B-lymphocytes

B-lymphocytes are cells that mature in the bone marrow and are involved in the humoral response, which defends the body against pathogens present in extracellular fluids. B cells produce antibodies that bind to the antigens on the surface of pathogens.

Gram-negative bacteria

Bacteria that have complex cell walls with less peptidoglycan but with lipopolysaccharides. Very toxic and hard to treat.

Gram-positive bacteria

Bacteria that have simple cell walls with much peptidoglycan.

prezygotic barriers

Barriers that impede mating or hinder fertilization.

reproductive isolation

Barriers that impede members of two different species fro producing fertile offspring.

postzygotic barriers

Barriers that prevent the hybrid zygote from becoming a fertile adult.

nucleic acid hybridization

Base pairing between a gene and a complementary sequence on another nucleic acid molecule.

purines

Bases with a double-ring structure.

pyrimidines

Bases with a single-ring structure.

metabolic pathway

Begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product.

foraging

Behavior associated with recognizing, searching for, capturing, and consuming food.

Behavior

Behavior is the way that organisms cope with their environments. Some animals behave in a programmed way to specific stimuli, while other behave according to some type of learning. The general types of behavior are: instinct, imprinting, classical conditioning, operant conditioning, and insight.

altruism

Behavior that benefits another without benefiting oneself.

semelparity

Big-bang reproduction.

major histocompatibility compex (MHC)

Binds to a fragment of an antigen within a cell and presents it on the surface of the membrane.

single-strand binding protein (SSB)

Binds to and stabilizes single-stranded DNA until it can be used as a template.

Bioenergetics

Bioenergetics is the study of how cells release the energy stored in chemical bonds holding molecules together.

Biogeography

Biogeography, or the study of the distribution of flora and fauna, have revealed a number of related species in widely separated regions of the world, supporting the theory of a common ancestor.

biota

Biotic factors.

RNA interference

Blocking gene expression by means of an miRNA silencing complex.

phosphodiester bonds

Bonds between phosphate group and pentose sugar in nucleic acids.

peptide bond

Bonds that connect amino acids.

Bone remodeling

Bone remodeling refers to the process of building or breaking down bones to store and release calcium and involves the parathyroid hormone and calcitonin.

osteoblasts

Bone-forming cells.

Brain hormone

Brain hormone is an insect hormone that targets ecdysone to be released in the prothoracic glands.

phylogenetic trees

Branching diagrams that depict hypotheses about evolutionary relationships.

glycolosis

Breaking glucose into two molecules of a compound called pyruvate.

electron transport chain

Breaks the fall of electrons to oxygen in several energy-releasing steps.

aposematic coloration

Bright warning colors in animals with a chemical defense.

induced fit

Brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction.

biogeographic realms

Broad patterns of distribution due to continental drift and barriers such as deserts and mountain ranges.

Bulk flow

Bulk flow is the one way movement of fluids brought about by pressure, such as the movement of blood through a blood vessel or fluids in xylem and phloem of plants.

veins

Bundles of xylem and phloem.

Calcitonin

Calcitonin is a hormone secretes by the thyroid. This hormone decreases blood concentration of calcium by concentrating free-floating calcium in the bones.

cryptic coloration

Camouflage; makes an organism difficult to spot.

facultative anaerobes

Can make enough ATP to survive using using fermentation or respiration.

Capillary action

Capillary action is the ability of water, or other liquids, to travel against gravity in a thin vessel and accounts for the ability of water to rise up the roots, trunks, and branches of trees.

cellulose

Carbohydrate component of plant cell walls.

Carbohydrates

Carbohydrates are organic compounds that contain carbon, hydrogen, and oxygen, usually in a ratio of 1:2:1.

Greenhouse Effect

Carbon dioxide and water vapor in atmosphere trap infrared radiation, re-reflecting it back toward earth.

calvin cycle

Carbon fixation process in photosynthesis. Forms sugar and other organic compounds.

Carbon

Carbon is an non mental element with symbol O and atomic number 6. It is the second most abundant element in living organisms and is present in all organic compounds.

Carboxyl group

Carboxyl groups are weak acids that are common in many organic molecules including amino acids and fatty acids.

tertiary consumer

Carnivore that eats carnivores.

secondary consumer

Carnivore that eats herbivores.

quaternary consumer

Carnivore that eats tertiary consumers.

messenger RNA (mRNA)

Carries genetic message from the DNA to he protein-synthesizing machinery of the cell.

foundation species

Cause physical changes in environment that affect community structure.

abdominal cavity

Cavity housing intestines.

lyse

Cell bursting.

mitosis

Cell division in which the nucleus divides into nuclei containing the same number of chromosomes.

interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases.

Cell sap

Cell sap is contained in the vacuole of mature plants and is a dilute fluid consisting of water, salts, glucose, and amino acids. Cell sap allows for storage and mechanical support in plants, especially non-woody plants.

cell differentiation

Cell specialization in structure and function.

peptidoglycan

Cell wall of prokaryotes, but NOT ARCHAEA. Made of a sugar polymer and polypeptide.

Cell-mediated immunity

Cell-mediated immunity is an immune response that does not involve antibodies, but rather involves the activation of phagocytes, cytotoxic T-cells, and various cytokines.

basement membrane

Cells at the base of an epithelial layer are attached to this.

glial cells

Cells in the nervous system that support, nourish, and protect neurons.

columnar epithelium

Cells shaped like bricks standing on end.

totipotent

Cells that are able to develop into any type of cell found in the body.

squamous epithelium

Cells that are like floor tiles.

chondrocytes

Cells that secrete cartilage.

Cellular respiration

Cellular respiration is a process performed by all organisms that produced ATP through the breakdown of nutrients. In cellular respiration, a sugar is combined with oxygen and water to produce carbon dioxide, water, and energy in the form of ATP.

Cellulose

Cellulose is a polysaccharide of beta glucose molecules that is a major part of the cell wall in plants and is used to lend structural support.

Centrioles

Centrioles are small, paired cylindrical structures found within microtubule organizing centers. Centrioles are most active during cellular division, during which they produce microtubules, which pull apart the replicated chromosomes. Centrioles are not found in plant cells.

primary structure

Chain of amino acids.

genetic drift

Change in allele frequencies due to chance.

microevolution

Change in genetic makeup of a population from generation to generation.

heterochrony

Change in the rate or timing of a developmental event; an organism's shape depends on relative growth rate of body parts.

translocation

Change to a chromosome in which a fragment of one chromosome attaches to a nonhomologous chromosome.

mutation

Changes in the nucleotide sequence in DNA.

Channel proteins

Channel proteins are membrane proteins that form channels that selectively allow the passage of certain ions or molecules.

voltage-gated ion channels

Channels that open or close in response to a change in the membrane potential.

discrete characteristics

Characteristics that are classified on an either-or basis, determined by a single gene locus.

quantitative characteristics

Characteristics that vary along a continuum, usually due to influence of two or more genes.

quantitative characters

Characters that vary in the population along a continuum (in gradations).

Charles Darwin

Charles Darwin was a 19th century British naturalist who sailed the world in a ship named the HMS Beagle. Darwin developed his theory of evolution based on natural selection after studying animals in the Galapagos Islands, and his work forms the basis of what we know about evolution. In his book entitled "On the Origin of Species," Darwin observed the following: Each species produces more offspring than can survive; these offspring compete with one another for limited resources; organism in every population vary; the fittest offspring, those with the most favorable traits, are most likely to survive and pass on their traits.

neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons.

histamine

Chemical stored in mast cells that triggers dilation and increased permeability of capillaries.

cytokines

Chemicals released by the immune system communicate with the brain.

Chitin

Chitin is a long polymer of a glucose derivative that is a principle component of the cell wall in fungi and of an arthropod's exoskeleton.

Choloroplasts

Chloroplasts are organelles involved in photosynthesis that are possessed by plants. Chloroplasts contain chlorophyll, a light capturing pigment that gives plants their green color.

Cholesterol

Cholesterol is a steroid that is found in the phospholipid bilayer because it helps stabilize membrane fluidity in animal cells.

autosomes

Chromosomes that are not directly involved in determining the sex of an individual.

recombinant chromosomes

Chromosomes that carry genes from each parent.

Cilia

Cilia are threadlike structures made out of microtubules that provide locomotive properties in single-celled organisms.

hormones

Circulating chemical signals that are formed in specialized cells, travels in body fluids, and act on specific target cells.

Citric acid

Citric acid, or citrate, is a six carbon molecule formed in the Krebs cycle by the joining of an Acetyl CoA molecule with an oxaloacetate. Citric acid then loses two carbons, in the form of carbon dioxide, to become oxaloacetate again.

Hox genes

Class of homeotic genes. Changes in these genes can have a profound impact on morphology.

exons

Coding segments of eukaryotic DNA.

Cofactors

Cofactors are inorganic elements that help catalyze reactions and are usually metal ions.

Cohesion

Cohesion refers to the tendency of water molecules to stick together and allows water to have a high surface tension.

transcription factors

Collection of proteins that mediate the binding of RNA polymerase and the initiation of transcription.

colonies

Collections of autonomously replicating cells.

acetylcholine

Common vertebrate neurotransmitter, especially in neuromuscular junctions.

nonequilibrium model

Communities are constantly changing after being buffeted by disturbances.

Comparative anatomy

Comparative anatomy is the study of the anatomy of various animals and has revealed similar structures in a wide variety of animals, supporting the theory of evolution.

agonistic behavior

Competition that determines who wins a prize, such as food or mates.

Competitive inhibition

Competitive inhibition is a process by which a chemical substance has a shape that fits the active site of an enzyme and competes with the substrate, effectively inhibiting the enzyme.

Complement proteins

Complement proteins are proteins that lyse the cell wall of an antigen. They are part of the nonspecific defense mechanisms of the immune system.

citric acid cycle

Completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.

Cdk

Complex of cyclin and kinase.

ribosomes

Complex particles that facilitate the orderly linking of amino acids into polypeptide chains.

ATP (adenosine triphosphate)

Composed of a sugar ribose, nitrogenous base adenine, and a chain of three phosphate groups bonded to it.

dehydration synthesis

Condensation reaction where molecules are connected by loss of a water molecule.

axon hillock

Cone shaped region of an axon where it joins the cell body.

McCarty, Avery, & MacLeod

Confirmed that the transforming agent in Griffith's experiment was DNA.

blood

Connective tissue made of plasma, erythrocytes, leukocytes, and platelets.

kinetochore microtubules

Connects the centrosome with the kinetochore in the centromere region of the chromosome.

addition rule

Considering mutually exclusive events, the probability of both occurring is the sum of the probabilities of each event.

ecosystem

Consists of all the organisms living in a community as well as all the abiotic factors with which they interact.

eukaryotic cells

Contain a nucleus and other organelles that are bound by membranes.

medulla oblongata

Contains centers that control several visceral functions, including breathing, heart and blood vessel activity, swallowing, vomiting, and digestion.

cell body

Contains most of a neuron's organelles and its nucleus.

Convergent evolution

Convergent evolution is the process by which two unrelated and dissimilar species come to have similar (analogous) traits, often because they have been exposed to similar selective pressures.

gene expression

Conversion of the information encoded in a gene first into messenger RNA and then to a protein.

adenylyl cyclase

Converts ATP to cyclic AMP in response to an extracellular signal.

coleoptile

Covers and protects the shoot as it grows upward.

capsule

Covers the cell wall in prokaryotes.

incomplete dominance

Creates a blended phenotype; one allele is not completely dominant over the other.

sexual recombination

Crossing over and shuffling of genes during meiosis.

Type III

Curve that drops sharply at the start then levels off once individuals reach a critical age, as seen in organisms that produce large numbers of offspring.

Type II

Curve that represents constant death rate over lifespan small animals and invertebrates.

Type I

Curve that shows low death rate at early and mid-life and drops at old age, as seen in humans and large animals.

Cytochromes

Cytochromes are iron-containing carriers that are carrier molecules in the electron transport chain. These carrier molecules hand down electrons to the end of the chain, where they are accepted by oxygen molecules. This system releases energy which is used to pump hydrogens across the inner membrane, setting up a proton gradient responsible for the production of ATP.

Cytoplasm

Cytoplasm is a thick solution that fills each cell and contains the organelles. The cytoplasm is composed of water, salt, and proteins and helps contain the organelles and may have important enzymes to break down large molecules.

Cytotoxic T-cells

Cytotoxic T-cells are a type of T-cells that recognize and kill infected cells.

Deoxyribonucleic acid (DNA)

DNA is a nucleic acid that has a deoxyribose sugar, a phosphate group, and a nitrogen base. DNA is important because it contains genes, and it is kept in the nucleus of cells.

Chromosomes

DNA is organized into large structures called chromosomes in the nucleus.

complementary DNA (cDNA)

DNA molecule made in vitro using mRNA as a template and the enzyme reverse transcriptase.

cloning vector

DNA molecules that can carry foreign DNA into a host cell and replicate there.

recombinant DNA

DNA produced by combining DNA from different sources

decent with modification

Darwin's way of referring to evolution.

radiometric dating

Dating using decay of radioactive isotopes.

territoriality

Defense of a space against encroachment by other individuals.

Dehydration synthesis

Dehydration synthesis, or condensation, is the process by which two molecules come together by the loss of a water molecule, such as the forming of maltose from two glucose molecules.

Dendrites

Dendrites are short extensions of the cell body that receive stimuli.

fibrous connective tissue

Dense tissue, large number of collagen fibers organized into parallel bundles. Includes ligaments and tendons.

light limitation

Depth to which light penetrates limits primary production.

hypertonic

Describes a solution that has a greater concentration of total solute.

hypotonic

Describes a solution that has a lesser concentration of total solute.

isotonic

Describes solutions that have an equal concentration of total solutes.

Desmosomes

Desmosomes hold adjacent animal cells tightly to each other and consist of a pair of discs associated with the plasma membrane of adjacent cells. Intermediate filaments within and outside the cells are attached to the discs.

Fredrick Sanger

Determined amino acid sequence of proteins.

Meselson & Stahl

Determined that DNA replication is semiconservative.

DNA sequencing

Determining the exact order of the base pairs in a segment of DNA.

Watson and Crick

Developed the double helix model of DNA.

Hersey-Chase Experiment

Devised an experiment that showed that only the DNA of T2 phages enters a bacterial cell during infection.

ultrametric trees

Diagram in which length of a branch reflects amounts of actual time.

phylograms

Diagram in which the length of a branch reflects number of changes in a DNA sequence.

cladogram

Diagram that shows patterns of shared characteristics.

Dialysis

Dialysis is the diffusion of solutes across a selectively permeable membrane.

cubiodal epithelium

Dice-shaped cells.

geometric isomer

Differ in arrangement around a double bond.

structural isomers

Differ in arrangement of atoms.

reproductive rate

Difference between per capita birth and per capita death rates.

geographic variation

Difference in variation between population subgroups in different areas.

sexual dimorphism

Differences between the sexes in secondary sexual characteristics.

nonsister chromatids

Different chromatids (maternal and paternal) of the same chromosome.

splicosome

Different particles that recognize splice sites are compiled in a large assembly. A complex of RNA and protein subunits. Removes introns from a transcribed pre-RNA segments.

Differentiation

Differentiation is the process by which a less specialized cell becomes a more specialized cell type, through homeotic genes.

resource partitioning

Differentiation of niches that enables similar species to coexist.

sporophyte

Diploid, or spore-producing, phase of an organism. Makes haploid spores by meiosis.

Disaccharides

Disaccharides are formed by two sugar molecules combining together through dehydration synthesis. An example of a disaccharide is maltose, make by linking two glucose molecules.

Erwin Chargaff

Discovered that DNA composition varies, but the amount of adenine is always the same as thymine and the amount of cytosine is always the same as guanine.

Frederick Griffith

Discovered transformation during an experiment that involved injecting mice with smooth S cells, rough R cells, heat-killed S cells, and heat-killed S cells with living R cells.

domains

Discrete structural and functional regions of proteins.

autoimmune diseases

Diseases caused when the immune system loses tolerance for self and turns against certain molecules in the body.

solvent

Dissolving agent of a solution.

Divergent evolution

Divergent evolution is the evolution of a new species from a current population, often as a result of geographic division.

cytokinesis

Division of the cytoplasm to form two separate daughter cells.

archaea

Domain of unicellular prokaryotes that have cell walls lacking peptidoglycan. Like eukaryotes, DNA contains histone proteins.

the three-domain system

Domains Bacteria, Archae, and Eukarya.

reducing agent

Donates electrons and becomes oxidized.

nuclear envelope

Double membrane perforated with pores that control the flow of materials in and out of the nucleus.

Gastrulation

During gastrulation, the zygote begins to change its shape. Cells now migrate into the blastocoel and differentiate to form three germ layers: the ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer). The ectoderm produces the epidermis, eyes, and the nervous system. The endoderm produces the inner linings of the digestive and respiratory tract as well as accessory organs such as the pancreas, gall bladder, and liver. The mesoderm gives rise to everything else, including bones and muscles.

Corpus luteum

During the luteal phase of menstruation, the ruptured follicle condenses into a little yellow blob called the corpus luteum, which is Latin for "yellow body." The corpus luteum secretes estrogen and progesterone, to promote the growth of glands and blood vessels in the endometrium to ready the body for pregnancy. Progesterone is important because without it the fertilized ovum cannot latch onto the uterus and develop into an embryo.

pyramids of biomass

Each on this pyramid tier represents standing crop.

trait

Each variant of a character.

Ecdysone

Ecdysone is a hormone that is promotes molting and the metamorphosis of a larva to a butterfly.

Ecological succession

Ecological succession refers to the predictable procession of plant communities over a relatively short period of time (decades or centuries).

Ecology

Ecology is the study of the interactions between living things and their environments.

photomorphogenesis

Effects of light on plant morphology.

secondary structure

Either an alpha helix or beta pleated sheet.

Electron microscopes

Electron microscopes are used to study detailed structures of a cell that cannot be easily seen or observed by light microscopy. They are capable of resolving structures a small as a few nanometers in length, such as individual virus particles or the pores on the surface of the nucleus.

Electrons

Electrons are negatively charged subatomic particles that spin around the nucleus.

Elements

Elements are substances that cannot be broken down into simpler substances by chemical means.

Embryology

Embryology is the study of the development of an organism. In the early stages of vertebrate development, all embryos look alike, supporting the theory of evolution.

comparative embryology

Embryos of vertebrates share many anatomical homologies.

proton-motive force

Emphasizes the capactiy of the gradient to preform work.

Endergonic reactions

Endergonic reactions are those in which the products have more energy than the reactants, so energy is required as an input.

Endocrine glands

Endocrine glands are specialized organs that secrete hormones in to the bloodstream, where they are carried throughout the body.

Endocytosis

Endocytosis is a means of a cell engulfing a substance too large to enter the cell. Endocytosis involves the cell membrane forming a pocket, pinching in, and forming either a vacuole or a vesicle.

kinetic energy

Energy associated with relative motion of objects.

first law of thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed.

net primary production (NPP)

Energy used by primary producers for respiration.

Entropy

Entropy is disorder, and is what the universe tends towards.

Enzyme specificity

Enzyme specificity is the concept that each enzyme catalyzes only one kind of reaction.

topoisomerase

Enzyme that functions in DNA replication, helping to relieve strain in the double helix ahead of the replication fork.

RNA polymerase

Enzyme that links together the growing chain of ribonucleotides during transcription.

Enzymes

Enzymes are organic catalysts, molecules that speed up the rate of a reaction without altering the reaction itself.

protein phosphatases

Enzymes that can rapidly remove phosphate groups from proteins.

Epinephrine

Epinephrine is a hormone produced by the adrenal medulla. Together with norepinephrine, epinephrine is responsible for the "fight-or-flight" response. Epinephrine increases heart rate, metabolic rate, and blood pressure.

nondisjunction

Error in meiosis in which homologous chromosomes fail to separate.

Estrogen

Estrogen is a sex hormone that is released by the ovaries that regulate the menstrual cycle.

Ethyl alcohol (ethanol)

Ethyl alcohol is a by-product of fermentation. Two ethyl alcohol molecules are produced for every one glucose that is broken down. Yeast cells and some bacteria make ethanol and carbon dioxide during anaerobic respiration.

Euglena

Euglena is a single celled flagellate in the protist kingdom.

Eukaryotic cells

Eukaryotic cells contain a nucleus and cytoplasm filled with membrane bound organelles. Eukaryotic cells include fungi, protists, plant cells, and animal cells.

game theory

Evaluates alternate strategies when outcome depends not only on each individual's strategy but also that of others.

evapotranspiration

Evaporation of water from soil plus transpiration from plants. Correlates with species richness.

second law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

Evolution

Evolution is the process by which living organisms change over time as a result of changes in heritable physical or behavioral traits. Evidence for evolution includes: paleontology, biogeography, embryology, molecular biology, and comparative anatomy.

adaptive radiation

Evolution of many new species from a common ancestor as a result of introduction to new environments.

macroevolution

Evolutionary change above the species level.

phylogeny

Evolutionary history of a species or group of species.

shared derived character

Evolutionary novelty unique to that clade.

Exergonic reactions

Exergonic reaction are those in which the products have less energy than the reactants, so energy is given off during the reaction.

Exocytosis

Exocytosis is the transportation of large particles out of the cell, by the fusion of a vesicle with the plasma membrane.

per capita death rate

Expected number of deaths in a population in a specified period of time.

Miller and Urey Experiment

Experiment that found that organic molecules can form in a strongly reducing atmosphere.

sign stimulus

External sensory stimulus that triggers a fixed action pattern.

glycogen

Extremely branched polymer of glucose.

anterior pituitary hormones

FSH, LH, TSH, STH, ACTH, and prolactin

Facilitated transport

Facilitated transport is the movement of lipid insoluble substances across the plasma membrane through special channel proteins.

Coenzymes

Factors that assist enzymes in catalyzing a reaction are known as coenzymes. Vitamins are examples of organic coenzymes. Coenzymes accept electrons and pass them along to another substrate. NAD+ and NADP+ are two examples of such enzymes.

growth factors

Factors that stimulate the cell to divide.

Feedback inhibition

Feedback inhibition is a system in which the formation of an end product inhibits an earlier reaction in the enzymatic sequence.

trophic structure

Feeding relationships between organisms in a community.

Fermentation

Fermentation is the process of ATP production under anaerobic conditions. In this process, after glycolysis pyruvic acid is converted to either lactic acid or ethyl alcohol and carbon dioxide. This process also produced NAD+, which allows glycolysis to continue. This process is not very efficient, and only results in a gain of 2 ATP for each molecule of glucose broken down.

Cleavage

Fertilization triggers the zygote to undergo a series of rapid cell divisions, by mitosis, called cleavage.

zygote

Fertilized egg. Carries one set of chromosomes from each parent.

reticular fibers

Fibers made of collagen fibers that are very thin and branched. Forma tightly woven fabric that joins connective tissue to adjacent tissues.

collagenous fibers

Fibers made of collagen.

elastic fibers

Fibers made of elastin.

genus

First part of scientific name.

relative fitness

Fitness of a particular genotype.

Flagella

Flagella are long projections on a cell used for motility. They are often found on single cell organisms but are sometimes present in larger organisms, such as on sperm.

thylakoid

Flattened membranes in the chloroplast where the light reactions take place.

wobble

Flexibility in the base-pairing rules in which the nucleotide at the 5' end of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position of a codon.

bioenergetics

Flow of energy through an animal. Limits its behavior, growth, reproduction.

stroma

Fluid inside the chloroplast where the Calvin Cycle happens.

Follicle-stimulating hormone (FSH)

Follicle-stimulating hormone is a hormone produced in the anterior pituitary that stimulates the follicle to grow in females, and spermatogenesis in males.

Follicle-stimulating hormone (FSH)

Follicle-stimulating hormone is a hormone secreted by the anterior pituitary that stimulates follicles in the ovaries to grow.

Fertilization

For fertilization to occur, the sperm must dissolve the corona radiata, a dense covering of follicle cells that surrounds the egg. Then the sperm must penetrate the zona pellucida, the zone below the corona radiata. When the egg is fertilized it forms a diploid cell called a zygote and undergoes a series of rapid cell division.

facilitators

Foundation species have positive effects on other species.

Fructose

Fructose is a monosaccharide that is a common sugar in fruits. It is a six-carbon sugar with the chemical formula C-6, H-12, O-6.

GABA

GABA is an important neurotransmitter that is secreted in the central nervous system and acts as an inhibitor.

reduction

Gain of electrons.

Ganglia

Ganglia are clumps of nerve cells similar to primitive brains that develop in animals that are more complex.

Gap juntions

Gap junctions are protein complexes that form channels in membranes and allow communication between the cytoplasm of adjacent animal cells or the transfer of small molecules and ions.

nodes of Ranvier

Gaps in the myelin sheath to which voltage-gated sodium channels are confined.

memory cells

General term for lymphocytes that are responsible for immunological memory and protective immunity.

X linked genes

Genes found on the X chromosome.

alternative RNA splicing

Genes giving rise to two or more different polypeptides depending upon which segments are treated as exons.

linked genes

Genes located on the same chromosome that tend to be inherited together in genetic crosses.

sex linked genes

Genes located on the sex chromosomes.

homeotic genes

Genes that determine basic features of where a body part is.

sickle-cell disease

Genetic disorder in which red blood cells have abnormal hemoglobin molecules and take on an abnormal shape.

Huntington's disease

Genetic disorder that causes progressive deterioration of brain cells. caused by a dominant allele. symptoms do not appear until about the age of 30.

Genetic drift

Genetic drift is a phenomenon that occurs in small population during which a gene pool will change over time by random chance. Genetic drift often occurs with the founder effect, when a small group of organisms moved to a new location, or the bottleneck effect, when a populations size is greatly and randomly reduced. Genetic drift is a violation of the Hardy-Weinberg law.

biogeography

Geographic distribution of species.

thymus

Gland in the thoracic cavity above the heart where T lymphocytes mature.

edocrine glands

Glands that secrete chemicals called hormones directly into the bloodstream.

Glucagon (alpha cell)

Glucagon is a hormone secreted by the pancreas. Glucagon is produced by alpha cells and stimulates the liver to convert glycogen into glucose and to release that glucose into the blood. Glucagon therefore increases the levels of glucose in the blood, raising the blood sugar level.

Glucocorticoids

Glucocorticoids are hormones produced in the adrenal cortex that increase the blood's concentration of glucose and help the body adapt to stress. It does this by promoting the conversion of amino acids and fatty acids to glucose.

Glucose

Glucose is the most abundant monosaccharide and is a six-carbon sugar with the chemical formula C-6, H-12, O-6. Glucose comes in two forms: alpha glucose and beta glucose, which differ simply by a reversal of the H and OH of the first carbon.

tryiacylglycerol

Glycerol and three fatty acids.

Glycerol

Glycerol is a simple polyol (sugar alcohol) compound that is found in fats.

Glycogen

Glycogen is a multi-branch polysaccharide of glucose that is the main storage of glucose in the body.

Glycogen

Glycogen is a multi-branched polysaccharide of glucose that serves as an energy store. Glycogen is stored in the liver and can easily be converted to glucose. Glucagon stimulates an increase of glycogen into glucose while insulin stimulates an increase of glucose into glycogen.

Glycolysis

Glycolysis, the splitting of glucose, is the first step in aerobic respiration. During glycolysis glucose, a 6-carbon molecule, is broken into two three carbon molecules called pyruvic acid. This breakdown of glucose also results in the net production of two molecules of ATP.

Golgi bodies

Golgi bodies , which look like stacks of flatten sacs, are organelles that participate in the processing of proteins in the cell. After the rough ER completes the synthesis of proteins, the Golgi bodies modify, process, ad sort the products. They then package and distribute the proteins to be sent out of the cell, packaging the products into vesicles.

ecological succession

Gradual recolonization of a disturbed area; species replaced by other species which are replaced by other species.

survivorship curves

Graph of the proportion of a cohort still alive at each age.

limiting nutrient

Greater limiting factor than light in oceans and lakes.

chlorophyll

Green pigment located within the chloroplasts.

population

Group of individuals of the same species living in the same area.

tissues

Groups of cells with a common structure and function.

gene families

Groups of related genes in an organism's genome.

Growth hormone (GH)

Growth hormone is a hormone produced in the anterior pituitary that stimulates growth throughout the body, targeting bones and muscles.

phototropism

Growth of a plant shoot toward or away from light.

diploid cell

Has two sets of chromosomes.

autopolyploid

Having more than two sets of chromosomes from a single species.

Heat capacity

Heat capacity refers to the ability of a substance to store heat and is the quantity of heat required to change the temperature of a substance by 1 degree. Water has a high heat capacity, allowing it to keep a fairly stable temperature in our bodies and in the environment.

Helper T-cells

Helper T-cells activate B-lymphocytes and other T-cells in responding to the infected cells.

Hardy-Weinberg Theorem

Helps measure changes in allele frequencies over time. Provides an "ideal" population to use as a basis of comparison.

primary consumer

Herbivore.

genetic variation

Heritable variations in a population.

Heterotrophs

Heterotrophs are living organism that rely on organic molecules for food, and are also known as consumers.

dendrites

Highly branched extensions that receive signals from other neurons.

pilli

Hollow tubes used to move cells or exchange DNA between bacteria by conjunction.

Homeobox genes

Homeobox genes are a type of homeotic gene that consists of homeoboxes (short, nearly identical DNA sequences) that encode proteins that bind to DNA; these proteins tell cells in various segments of the developing embryo what type of structures to make.

Homeostasis

Homeostasis refers to the stable conditions of your body, including steady heart and respiratory rates. The parasympathetic system works to keep the body at homeostasis.

Homeotic genes

Homeotic genes control the development of the embryo and include homeobox genes that tell cells in the developing embryo what type of structure to make.

synapsis

Homologous chromosomes pair up, aligned gene by gene.

orthologous genes

Homologous genes passed in a straight line from one generation to the next.

paralogous genes

Homologous genes that are found in the same genome as a result of gene duplication.

Homologous structures

Homologous structures are similar structures that serve different functions, such as a human's arm, a dog's leg, a bird's wing, and a whale's fin, which look similar but serve different purposes. Homologous structures point to a common ancestor and support evolution.

genetic annealing

Horizontal gene transfer between different bacteria and archae.

insulin

Hormone produced by the pancreas that helps to decrease blood sugar.

Hormones

Hormones are chemicals that are produced in one region of the body to act on target cells in another region. Hormones are produced in endocrine glands. Hormones have a number of functions including regulating growth, behavior, development, and reproduction.

Negative feedback system (hormones)

Hormones operate by a negative feedback system. That is, an excess of the hormone will signal the endocrine gland to temporarily shut down production.

Amine

Hormones that are amines cannot get into a cell by simple diffusion, and must bind to a receptor protein on the cell membrane of the target cell.

Hox genes

Hox genes are a subset of homeobox genes that specify the position of body parts in the developing embryo.

Human chorionic gonadotropin (HCG)

Human chorionic gonadotropin is a hormone produced by an embryo following implantation. The hormone helps maintain the uteral lining during pregnancy. The presence of HCG is detected in pregnancy tests.

artificial selection

Humans modifying species for desired traits through selective breeding.

autosomal dominant disorders

Huntington disease and achondroplasia

hybrid breakdown

Hybrid is fertile, but when they breed the next generation is sterile.

Hydrogen bonds

Hydrogen bonds are intermolecular attractions that form when a hydrogen bond that is covalently bonded to one electronegative atom that it also attracted to another electronegative atom. Hydrogen bonds are individually weak but are strong when present in large numbers.

Hydrogen

Hydrogen is an element with symbol H and atomic number 1. Hydrogen combines with non-metallic elements to form water and other organic compounds.

Hydrolysis

Hydrolysis is the opposite process of dehydration synthesis by which molecules are broken up by the addition of a water molecule, such as the formation of two glucose molecules from a maltose.

Hyperthyroidism

Hyperthyroidism is a condition that occurs in individuals who regularly release too much thyroxine. These people have a fast metabolic rate and tend to be irritable and nervous.

Hypothyroidism

Hypothyroidism is a condition that occurs in individuals who have too little thyroxine circulating in their bloodstream. They exhibit a slow metabolic rate and tend to be sluggish and overweight.

sister chromatids

Identical copies of a chromosome; full sets of these are created during the S subphase of interphase.

Saturated

If a fatty acid is saturated, it means it has a single covalent bond between each pair of carbon atoms.

Unsaturated

If a fatty acid is unsaturated it means it has adjacent carbons that are joined by double bonds instead of single bonds.

Polypeptide

If a group of amino acids are joined together in a chain, the resulting organic compound is a polypeptide, which is the primary structure of a protein.

dioecious

If staminate and carpellate flowers are on different plants.

monoecious

If staminate and carpellate flowers are on the same plant.

coenzyme

If the cofactor is an organic molecule.

secondary immune response

Immune response after the body has already been exposed to a specific antigen. Response is faster, of greater magnitude, and more prolonged.

primary immune response

Immune response the first time the body is exposed to a particular antigen. Does not peak until 10-17 days after exposure.

passive immunity

Immunity conferred by transferring antibodies from an individual who is immune to a pathogen to another individual.

innate immunity

Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens.

acquired immunity

Immunity that is present only after exposure and is highly specific.

noncompetitive inhibitors

Impede enzymatic reactions by binding to another part of the enzyme (other than the active site).

dopamine

Important neurotransmitter in the CNS that acts on the sympathetic nervous system.

Polarized

In a resting neuron cell, there is a potential difference between the inside and the outside of the cell. The resting membrane potential is always negative inside the cell, with a -70 mV charge. This polarized cell is the result of Na-K-ATPase pumps that pump 2 potassium ions into the cell and 3 sodium ions out of the cell.

Extra-embryonic membranes

In addition to the primary germ layers, some animals, such as chickens, have extra-embryonic membranes. The four extra-embryonic membranes include: the yolk sac, amnion, chorion, and allantois. These extra membranes are common in birds and reptiles.

anther

In an angiosperm, the terminal pollen sac of a stamen, where pollen grains containing sperm-producing male gametophytes form.

endosperm

In angiosperms, a nutrient-rich tissue formed by the union of a sperm with two polar nuclei during double fertilization. Provides nourishment to the developing embryo in angiosperm seeds.

centriole

In animal cells, a cytoplasmic organelle that organizes the mitotic spindle fibers during cell reproductions.

conjugation

In bacteria, the direct transfer of DNA between two cells that are temporarily joined.

fibroblasts

In connective tissue, cells that secrete the proteins of the fibers.

Directional selection

In directional selection, one phenotype is favored at one of the extremes of normal distribution.

Disruptive selection

In disruptive selection, extreme traits are favored and natural selection works against common traits. For example, in elephant seals, females are selected to be small and males are selected to be large.

countercurrent heat exchanger

In ectotherms, a circulatory adaptation that is an arrangement of blood vessels that warm or cool the blood.

ovary

In flowers, the portion of a carpel in which the egg-containing ovules develop.

Noncompetitive inhibition

In noncompetitive inhibition, the inhibitor binds with the enzyme at a site other than the active site and inactivates the enzyme by altering its shape.

polyploidy

In plants, the result of an extra set of chromosomes during cell division.

terminator

In prokaryotes, a special sequence of nucleotides in DNA that marks the end of a gene.

denaturation

In proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. In DNA, the separation of the two strands of the double helix.

Stabilizing selection

In stabilizing selection, organisms in a population with extreme traits are eliminated, favoring organisms with common traits. An example is birth weight in humans; abnormally small or large babies have a lower chance of surviving both and infancy.

MHC markers

In the MHC system, MHC molecules bind to peptide fragment from foreign pathogens and display them on the cell surface for recognition by T cells.

photolysis

In the thylakoid membranes of a chloroplast during light-dependant reactions, two molecules of water are split to form oxygen, hydrogen ions, and electrons.

barr body

Inactivated X chromosome in females

imprinting

Includes both learning and innate components, generally irreversible.

Central Nervous System (CNS)

Includes the brain and spinal cord.

behavioral isolation

Incompatible courtship rituals, pheromones, or bird songs.

vasodialation

Increases in the diameter of superficial blood vessels; cools the body.

mate choice copying

Individuals in a population copy mate choice of others.

fitness

Individuals whose inherited traits confer an advantage have a better chance of surviving in a given environment and will leave more offspring.

auxin

Indoleacetic acid (IAA), a natural plant hormone that has a variety of effects, including cell elongation, root formation, secondary growth, and fruit growth.

Induced fit

Induced fit refers to when an enzyme has to change its shape slightly to accommodate the shape of the substrates.

Induction

Induction is the process in embryonic development by which the presence of one tissue determines the differentiation of another tissue.

Inflammatory response

Inflammatory response is a defense mechanism of the immune system in which damaged or infected cells release chemicals such as histamine, which causes inflammation. Inflammation allows for increased blood flow to the area, strengthening the immune response.

top-down model

Influence moves from top trophic levels to bottom. (V <-- H)

cristae

Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.

epigenetic inheritance

Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence.

inflammtory response

Innate response with the purpose of containing a site of damage, localizing the response, eliminating the invader and restore tissue function.

Inorganic compounds

Inorganic compounds are compounds that do not contain carbon atoms (except for some simple carbon compounds such as carbon oxides)

parasitoidism

Insects that lay eggs on or in living host; larvae feed on body of host, eventually killing it. (+/-)

Instinct

Instinct is an inborn, unlearned behavior. Sometimes instinctive behavior is triggered by environmental signals called releasers - a small part of the environment that is perceived.

Insulin (beta cell)

Insulin is a hormone secreted by the pancreas, where it is made by beta cells. Insulin targets the liver and muscle cells and has the opposite effect that glucagon does; insulin stimulates the liver to convert glucose into glycogen, lowering the blood sugar level.

Integral proteins

Integral proteins are firmly bound to the plasma membrane and are amphipathic.

integral proteins

Integral proteins that span the membrane.

transmembrane proteins

Integral proteins that span the membrane.

conservation biology

Integrates ecology, physiology, molecular biology, genetics and evolutionary biology to conserve biological diversity.

commensalism

Interaction between species that benefits one but neither helps or harms the other. (+/0)

Intercellular junctions

Intercellular junctions are strucutres between cells that allow neighboring cells to form strong connections with each other, prevent passage of materials, or establish rapid communication between adjacent cells. The three types of intercellular contact in animal cells are: desmosomes, gap junctions, and tight junctions.

cerebral cortex

Interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center.

antibiotics

Interfere with production of peptidoglycan; harm bacteria but not eukaryotes.

Interferons

Interferons are a group of signaling proteins released by host cells in response to a pathogen. They inhibit viral replication and activate surrounding cells that have antiviral actions.

Interneurons

Interneurons are links between sensory neurons and motor neurons, found in the brain or spinal cord.

transfer RNA (tRNA)

Interpreter of a series of codons along a mRNA molecule.

mutualism

Interspecific interaction that benefits both species. (+/+)

Interstitial cells

Interstitial cells are supporting tissue in the testis that produce testosterone and other androgens.

variation

Is demonstrated by the differences in appearance that offspring show from parents and siblings.

acetyl-CoA

Is formed when pyruvate first enters into the mitochondria via active transport.

island equilibrium model

Islands great for study due to isolation and limited size; can study species diversity and extinction rates.

radioisotopes

Isotopes that have unstable nuclei and undergo radioactive decay.

cooperativity

It amplifies the response of enzymes to substrates.

Jean Baptiste de Lamarck

Jean-Baptiste de Lamarck was an 18th century scientist who proposed a theory explaining the variety of life on Earth. Lamarck believed that acquired traits were inherited and passed on to offspring, a theory referred to as the "law of use and disuse." This theory was very popular in Darwin's day, although we now know it to be wrong.

ligaments

Join bones to bones at joints.

Juvenile hormone

Juvenile hormone is a hormone that causes larvae to retain their characteristics; the concentration of this hormone decreases as the larva undergoes metamorphosis.

thermal energy

Kinetic energy associated with the random movement of molecules or atoms.

Lactic acid

Lactic acid is a by-product of fermentation. Two lactic acid molecules are produced for every one glucose that is broken down. Lactic acid is produced by some bacteria during anaerobic respiration and by muscles when they do not get enough oxygen.

ecological footprint

Land and water area appropriated by each nation as a resource to consume or to absorb the waste it generates.

cerebrum

Largest part of the brain; responsible for voluntary muscular activity, vision, speech, taste, hearing, thought, and memory.

operant conditioning

Learning based on the consequences of responding.

Learning

Learning is a form of behavior that refers to a change in a behavior brought about y an experience.

social learning

Learning through observing others.

energy hypothesis

Length of a food chain is limited by the inefficiency of energy transfer.

r-selected species

Life history traits maximize reproductive success in uncrowded environments. Many small offspring that mature quickly, little if any parental care.

K - selected species

Life history traits sensitive to population density. Small number of large offspring, extensive parental care, repeated reproduction.

Light microscopes

Light microscopes, also known as compound microscopes, are used to study stained or living cells. They can magnify the size of an organism up to 1,000 times.

food web

Linked food chains.

nitric oxide (NO)

Local regulator that regulates blood oxygen levels, A gas produced by many types of cells that functions as a local regulator and as a neurotransmitter.

dynamic stability hypothesis

Long food chains are less stable than short chains.

axon

Long nerve fiber that conducts away from the cell body of the neuron.

hibernation

Long-term torpor that is an adaptation to winter cold and food scarcity.

oxidation

Loss of electrons.

Luteal Phase

Luteal stage During the luteal stage, the ovum has moved into the fallopian tube and the follicle has been ruptured and left behind in the ovary. The ruptured follicle (now a fluid filled sac) continues to function in the menstrual cycle, condensing into a little yellow blob called the corpus luteum. The corpus luteum continues to secrete estrogen and begins to produce progesterone, which gets the body ready for pregnancy by promoting the growth of glands and blood vessels in the endometrial. This stage lasts about 13 to 15 days, until the corpus luteum shuts down.

Luteinizing hormone (LH)

Luteinizing hormone is a hormone produced in the anterior pituitary that causes the release oft he ovum during the menstrual cycle in females, and testosterone production in males.

Luteinizing hormone (LH)

Luteinizing hormone is a hormone secreted by the anterior pituitary in response to an increase in estrogen released by the follicle in the ovary. An increase in estrogen causes a sudden surge in LH which triggers ovulation - the release of the follicle from the ovary.

Lymph

Lymph is a clear, watery fluid formed from interstitial fluid that runs in networks of vessels as part of the lymphatic system. Lymph contains white blood cells that attack bacteria in the blood.

B lymphocytes (B cells)

Lymphocyte that matures in the bone marrow and secretes antibodies.

T lymphocytes (T cells)

Lymphocyte that matures in the thymus and acts directly against antigens in cell-mediated immune responses.

Lymphocytes

Lymphocytes are small white blood cells present in the lymphatic system that fight infection. They multiple rapidly when they come in contact with a foreign substance.

Lysosomes

Lysosomes are organelles that carry digestive enzymes, which they use to break down old, worn out organelles, debris, or large ingested particles. The lysosomes help keep the cytoplasm clear of unwanted materials. Lysosomes contain hydrolytic enzymes that function at acidic pH, which is enclosed inside the lumen of the lysosome.

cartilage

Made of collagenous fibers in matrix of chondroitin sulfate.

steroids

Made of four rings of carbon.

heterozygous advantage

Maintains recessive alleles in a population,

thalamus

Major input center for sensory information going to the cerebrum and the main output center for motor information leaving the cerebrum.

biome

Major types of ecological association that occupy broad geographic regions.

cloning

Making a genetically identical copy of DNA or of an organism.

cytoplasmic determinants

Maternal substances in egg that influence the course of early development.

carrying capacity (K)

Maximum population size that a particular environment can support.

free energy

Measures the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell.

glycolipids

Membrane carbohydrates that are covalently bonded to lipids.

glycoproteins

Membrane carbohydrates that are covalently bonded to proteins.

mucous membrane

Membrane that secretes mucus that lubricates the surface of organs and keeps them moist.

liposomes

Membrane-bound droplets that form when lipids are added to water.

synaptic vesicles

Membrane-bounded compartments in which synthesized neurotransmitters are kept.

thylakoids

Membranous structures within a chloroplast that serve as the site for light harvesting in photosynthesis.

Menstruation

Menstruation, or the flow phase, is a phase of the menstrual cycle that occurs after the corpus luteum has turned off. During this phase the uterus starts to reabsorb the tissue that the progesterone encouraged it to grow. Some of the tissue cannot be reabsorbed and is shed, through bleeding.

catabolism

Metabolic pathways that break down molecules, releasing energy.

anabolism

Metabolic pathways that construct molecules, requiring energy.

anabolic pathways

Metabolic pathways that consume energy to build complicated molecules from simpler ones.

catabolic pathways

Metabolic pathways that release energy by breaking down complex molecules into simpler compounds.

MRSA

Methicillin-resistant Staphylococcus aureus.

Microfilaments

Microfilaments are thin, rodlike structures composed of the protein actin and are involved in cell mobility and muscle contraction.

stomata

Microscopic pores in the leaf which lets CO2 in and O2 out. Also where water is lost.

asters

Microtubules and fibers that radiate out from the centrioles.

Microtubules

Microtubules, which are made up of the protein tubulin, participates in cellular division and movement. These small fibers are an integral part of centrioles, cilia, and flagella.

Miller and Urey

Miller and Urey were scientists who, in 1953, simulated the conditions of primitive Earth in a laboratory. They put the gases theorized to be abundant in the early atmosphere into a flask, struck them with electrical charges in order to mimic lighting, and organic compounds similar to amino acids appeared.

bone

Mineralized connective tissue.

Mineralocorticoids

Mineralocorticoids are hormones produced by the adrenal cortex that help the body retain sodium and water in the kidneys. They accomplish this by promoting the reabsorption of sodium and chlorine, which together from common salt. When salt is absorbed, so it water.

M phase

Mitosis and cytokinesis.

intermediate disturbance

Moderate levels of disturbance can create conditions that foster greater species diversity.

poly-A tail

Modified end of the 3' end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides.

prostaglandins

Modified fatty acids that are produced by a wide range of cells.

polar

Molecule with partial charges. Mixes with water.

amphipathic

Molecules are said to be this when it has regions that are both hydrophilic and hydrophobic.

pigments

Molecules that absorb, reflect, or transmit light.

beta glucose

Monomer for cellulose and chitin.

alpha glucose

Monomer for starch and glycogen.

Monosaccharides

Monosaccharides are the simplest sugars which serve as an energy source for cells. The two most common monosaccharides are glucose and fructose.

Morphogen

Morphogen is a chemical substance released by organizer cells that moves form one tissue to the target tissue, helping with induction in a developing embryo.

Morphogenesis

Morphogenesis is the process by which a single celled egg develops into a complex, multicellular organism.

mechanical isolation

Morphological differences prevent fertilization.

neutrophils

Most abundant white blood cell., The most abundant type of white blood cell. Phagocytic and tend to self-destruct as they destroy foreign invaders, limiting their life span to a few days.

missense mutations

Most common type of mutation, a base pair mutation in which the new codon makes sense in that it still codes for an amino acid.

Motor (effector) neurons

Motor neurons transmit the impulse to muscles or glands to produce a response. The muscle will respond by contracting, or the gland will respond by secreting a substance.

demographic transition

Movement from a high birth rate, high death rate to a low birth rate, low death rate.

species transplant

Movement of a species to areas where it was previously absent.

dispersal

Movement of individuals away from centers of high population density or their area of origin.

emigration

Movement out of population. Decreases population size.

taxis

Movement toward or away from a stimulus.

stratified epithelium

Multiples tiers of cells.

effector cells

Muscle cells or gland cells that carry out the body's response to stimuli.

cardiac muscle

Muscle that is branched, striated, singe nucleated.

smooth muscle

Muscle that is not striated, is single nucleated.

skeletal muscle

Muscle that is striated, multinucleated.

frameshift mutation

Mutation occurring when the number of nucleotides inserted or deleted is not a multiple of three, resulting in improper grouping of nucleotides into codons.

Myelin sheath

Myelin sheath is a substance produced by Schwann cells surrounding a neuron. Myelin sheath insulates the neuron and allows for a quicker propagation of an impulse, since the impulse can now jump from node to node.

endorphins

Natural analgesics that decrease pain perception.

sexual selection

Natural selection for mating success.

Natural selection

Natural selection is the driving force of evolution and refers to the differential survival and reproduction of individuals due to differences in phenotype and general fitness.

kin selection

Natural selection that favors altruistic behaviors by enhancing reproductive success of relatives.

corpus callosum

Nerves that enable communication between the right and left cerebral hemispheres.

cytoskeleton

Network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement.

Neurons

Neurons are specialized cells in the nervous system that transmit nerve signals. A neuron consists of a cell body, dendrites, and an axon. The three types of neurons are sensory neurons, motor neurons, and interneurons.

sensory neurons

Neurons that carry incoming information from the sense receptors to the central nervous system.

motor neurons

Neurons that carry outgoing information from the central nervous system to the muscles and glands.

neurosecretory cells

Neurons that secrete neurohormone rather than neurotransmitter.

epinephrine

Neurotransmitter secreted by the adrenal medulla in response to stress. Also known as adrenaline.

Neutral fats

Neutral fats are non polar, uncharged triglycerides that have no acidic or basic groups.

Neutrons

Neutrons are uncharged subatomic particles found in an atom's nucleus.

immigration

New individuals moving into population. Increases population size.

Nitrogen

Nitrogen is an element with the symbol N and atomic number 7. In biology, nitrogen is important as it is found in a number of organic compounds and is used in fertilizers and antibiotics.

nonpolar

No partial charges. Do not mix with water.

promiscuous

No strong pair bonds or lasting relationships.

cofactor

Non-protein helpers that may be bound tightly to the enzyme as a permanent resident, or may bind loosely and reversibly along with the substrate.

introns

Noncoding segments of nucleic acid that lie between coding sequences.

abiotic factors

Nonliving components of environment.

detritus

Nonliving organic maters such as remains of dead organisms, feces, fallen leaves, dead wood.

crossing over

Nonsister chromatids exchanging DNA segments.

Norepinephrine

Norepinephrine is an important neurotransmitter that is released between neurons within the central nervous system.

keystone species

Not necessarily abundant, but exert a strong control on community structure due to a pivotal ecological role.

Nucleic acids

Nucleic acids are organic compounds that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. They are made up of simple units called nucleotides and include deoxyribonucleic acid and ribonucleic acid.

Nucleotides

Nucleotides are simple units that make up nucleic acids. A nucleotide consists of a nitrogen base, a phosphate group, and a five carbon sugar (ribose or deoxyribose).

infant mortality

Number of infant deaths per thousand live births.

pyramids of numbers

Number of organisms at each trophic level.

detritivores

Obtain energy from detritus.

anaerobic

Occurs by fermentation, which generate ATP solely by substrate-level phosphorylation.

exocytosis

Occurs when a cell secretes certain biological molecules by the fusion of vesicles with the plasma membrane.

endocytosis

Occurs when a cell takes in biological molecules and particulate matter by forming new vesicles from the plasma membrane.

potential energy

Occurs when an object is not moving, but may still posses energy.

recombinant types

Offspring who have inherited new combinations of genes and have phenotypes that don't match either parental phenotypes.

parental types

Offspring with a phenotype that matches one of the parental phenotypes.

Oils

Oils are a type of lipid and are triglycerides that are liquid.

stromatolites

Oldest known fossils formed from many layers of bacteria and sediment.

Memory T-cells

Once activated, T cells multiply and give rise to clone cells, some of which become memory T-cells. Memory T-cells recognize pathogen they have encountered before, allowing for a quicker immune response in a second exposure.

Repolarized

Once sodium ions have flooded the neuron, the sodium channels close. At this point, the potassium channels open and the potassium ions rush out of the axon, and the electrical changes reverse again, so it is negative on the inside, and positive on the outside. Once the charges are restores, the section of the neuron is said to be repolarized.

polyandry

One female, several males.

monogamous

One male mating with one female.

polygyny

One male, several females.

allele

One of the alternative forms of a gene that governs a characteristic, such as hair color.

enteric division

One of three divisions of the autonomic nervous system; consists of networks of neurons in the digestive tract, pancreas, and gallbladder.

asexual reproduction

One parent produces a genetically identical offspring by mitosis.

haploid

One set of chromosomes.

10% rule

Only 10% of the total energy produced at each trophic level is available to the next level. The amount of energy passed up to the levels of the food pyramid reduces as you go up.

cyclic photophosphorolation

Only Photosystem I works. ATP is made, no oxygen is produced, no water is split, no NADPH is made.

chlorophyll a

Only pigment that can participate directly in the light reactions.

Oparin and Haldane

Oparin and Haldane were two scientists who proposed in the 1920s that the primitive atmosphere contained the following gases: methane, ammonia, hydrogen, and water. They believed that these gases collided, producing chemical reactions that eventually led to organic molecules.

Organelles

Organelles are small units suspended in the cytoplasm which carry out a specific function to help the cell.

chloroplasts

Organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis.

Organic compounds

Organic compounds are compounds that contain carbon and include carbohydrates, lipids, proteins, and nucleic acids.

chemoautotrophs

Organisms that use hydrogen sulfide or other chemicals as energy source instead of light.

photoautotrophs

Organisms that use light as a source of energy to synthesize organic substances.

true-breeding

Organisms that, when reproducing, create offspring of all the same variety.

Organizers

Organizers are cells that release a chemical substance (a morphogen) that moves from one tissue to the target tissue. Organizers are involved in induction in embryonic development.

speciation

Origin of new species and the source of biological diversity.

Osmosis

Osmosis is the diffusion that involves the movement of water. When osmosis occurs through a lipid bilayer it moves through membrane proteins called aquaporins.

Ova

Ova are egg cells that are manufactured in the ovaries. During menstruation, an ovum is released from the ovaries and travels to the fallopian tubes, where it may be fertilized.

Ovulation

Ovulation refers to the release of the follicle from the ovary and is triggered by the hormone luteinizing hormone. After being released, the ovum travels into the fallopian tubes.

Oxaloacetate

Oxaloacetate is a four carbon molecule that combines with Acetyl CoA in the Krebs Cycle to form citric acid. This citric acid then loses two carbons as carbon dioxide, to form oxaloacetate again, so that the Krebs cycle can begin again.

Oxidative phosphorylation

Oxidative phosphorylation refers to the process by which ATP synthase uses the flow of protons into the matrix to combine ADP and P, producing ATP. Oxidative phosphorylation produces 32 ATP.

Oxygen

Oxygen is an element with symbol O and atomic number 8. It is a highly reactive nonmetal and oxidizing agent. In living organisms, oxygen is used in respiration and in a number of organic molecules.

Oxytocin

Oxytocin is a hormone secreted by the posterior pituitary that stimulates contraction of uterus and ducts of mammary glands. This hormone is made in the hypothalamus, but stored in the posterior pituitary.

homologous chromosomes

Pair of chromosomes that are the same size, same appearance and same genes.

Paleontology

Paleontology, or the study of fossils, has revealed the great variety of organisms (most of which have died off) and the major lines of evolution.

Paramecium

Paramecium is a unicellular ciliated protozoan.

ectoparasites

Parasites that feed on external surface of host.

endoparasites

Parasites that live within the body of their host.

Parasympathetic nervous system

Parasympathetic nervous system is a part of the autonomic system that works antagonistically to the sympathetic nervous system, returning the body to homeostasis after a stress response.

Parathyroid hormone

Parathyroid hormone is released by parathyroids and it increases blood calcium levels if the blood needs more calcium. Thus, the parathyroid hormone has the opposite effect as calcitonin.

monohybrids

Parents that are heterozygous for one character.

dihybrids

Parents that are heterozygous for two characters.

light reaction

Part of photosynthesis that involves light. ATP and NADPH are produced. Takes place on the thylakoid membrane.

facilitated diffusion

Passive diffusion that is aided by transport proteins, but that does not require cellular energy.

dispersion

Pattern of spacing among individuals.

macroclimate

Patterns on the global, regional and local level.

trophic efficiency

Percentage of production transferred from one trophic level to the next.

Peripheral proteins

Peripheral proteins are proteins that are loosely associated with the lipid bilayer and only temporarily attach to the membrane. They are located on the inner or outer surface of the membrane.

Phagocytosis

Phagocytosis is endocytosis during which the cell takes in solids.

Pheromones

Pheromones are hormones that help animals to communicate with members of their species and attract the opposite sex.

Phospholipid

Phospholipids are a class of lipids that contain two fatty acids tails and one negatively charged phosphate head. They are extremely important in their unique properties with regard to water.

karyotype

Photograph of chromosomes grouped in order and in pairs.

Photosynthesis

Photosynthesis is a process that involves the transformation of solar energy into chemical energy. Plants take carbon dioxide, water, and energy (in the form of sunlight) and use them to produce glucose.

photoautotrophs

Photosynthetic bacteria.

noncyclic photophosphorolation

Photosystem II performs photolysis to provide electrons for the electron transport chain that drives a chemiosmotic gradient that produces ATP.

torpor

Physiological state in which activity is low and metabolism decreases.

Pinocytosis

Pinocytosis is endocytosis during which the cell ingests liquids.

Pioneer organisms

Pioneer organisms are the first organisms that inhabit an area in ecological succession. Often lichen serve as the pioneer organism. After they make the area more habitable, lichens are replaced, since they can't compete with the new plants for sunlight and minerals.

metaphase plate

Plane midway between the two poles of the cell where chromosomes line up during metaphase.

gibberellins

Plant hormones that promote stem and leaf elongation

etiolation

Plant morphological adaptations for growing in darkness.

Plastids

Plastids are double membrane bound organelles that temporarily store starch in plants. Plastids include chloroplasts, chromoplasts, and leucoplasts.

chitin

Polysaccharide found in arthropod exoskeletons and fungal cell walls.

Polysaccharides

Polysaccharides are made up of many repeated unites of monosaccharides, and is therefore a type of polymer. The most common polysaccharides are starch, cellulose, and glycogen. Polysaccharides are often storage forms of sugar.

exponential growth

Population increase under ideal conditions, when r > 0. Forms a J-shaped curve.

Post-zygotic barriers

Post-zygotic barriers are barriers related to the inability of the hybrid to produce offspring, such as the sterile mule.

Pre-zygotic barriers

Pre-zygotic barriers are barriers that prevent fertilization, which could be geographic or behavioral differences, such as if two species reproduce at different times of the year, which is known as temporal isolation.

life expectancy at birth

Predicted average length of life at birth.

aminocentesis

Prenatal diagnostic technique that involves inserting a needle to obtain a sample of amniotic fluid that surrounds the fetus.

chorionic villus sampling (CVS)

Prenatal diagnostic technique that involves taking a sample of tissue from the chorion.

climate

Prevailing weather conditions of an area.

coefficient of relatedness

Probability that if two individuals share common parent or ancestor, a particular gene present in one will be present in other.

chemiosmosis

Process by which a Hydrogen pump pumps protons into the thylakoid membrane. H+ passively flows through the ATP synthase which leads to the creation of ATP.

RNA splicing

Process by which the introns are removed from RNA transcripts and the remaining exons are joined together.

phagocytosis

Process in which extensions of cytoplasm surround and engulf large particles and take them into the cell.

crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

phosphoralation

Process of adding a phosphate group.

thermoregulation

Process of maintaining an internal temperature within a tolerable range.

inositol triphosphate

Produced by cleavage of a certain kind of phospholipid in the plasma membrane.

spores

Produced by meiosis. Grow into haploid organisms by mitosis.

Progesterone

Progesterone is a sex hormone that is released by the ovaries that regulate the menstrual cycle.

apoptosis

Programmed cell death.

Prokaryotic cells

Prokaryotic cells are much smaller than eukaryotic cells and lack both a nucleus and membrane bound organelles. In a prokaryote, circular DNA lies free in the nucleoid . Most prokaryotes have a cell wall composed of peptidoglycan and may also have ribosomes or flagella.

Prolactin

Prolactin is a hormone produce in the anterior pituitary that stimulates the mammary glands to produce milk.

allele frequency

Proportion of an allele in a gene pool.

allometric growth

Proportioning that gives a body a specific form.

ozone layer

Protective layer in atmosphere that shields earth from UV radiation.

interferon

Protein produced by cells in response to being infected by a virus; helps other cells resist the virus.

antibodies

Protein that is produced by lymphocytes and that attaches to a specific antigen.

heat-shock proteins

Proteins that help maintain integrity of other proteins that would normally be denatured in extreme heat.

Protons

Protons are positively charged subatomic particles that are found in an atom's nucleus.

astrocytes

Provide structural and metabolic support for neurons.

Puberty

Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. In males, testosterone and cortical sex hormones, is responsible for the development of the voice and secondary sex characteristics, such as the deepening of the voice, facial and body hair, and muscle growth.

Pyruvic acid

Pyruvic acid is a 3 carbon molecule produced by the splitting of a glucose in glycolysis. Pyruvate is important because it goes on to be broken down into acetyl CoA.

Ribonucleic acid (RNA)

RNA is a nucleic acid that has a ribose sugar, a phosphate group, and a nitrogen base. RNA is important because it has an essential role in protein synthesis.

ribosomal RNA (rRNA)

RNA molecules that construct ribosomal subunits.

ribozymes

RNA molecules that function as enzymes.

retrovirus

RNA virus that carries with it reverse transcriptase (HIV)

siRNAs (small interfering RNAs)

RNAs of similar size and functions as miRNAs that inhibit gene expression.

nucleic acid probe

Radioactively labeled nucleic acid molecule used to tag a particular DNA sequence.

mutations

Random errors in gene replication that lead to a change in the sequence of nucleotides. The source of all genetic diversity.

Random mutation

Random mutations are the random changes in the genes of individuals, which allows for genetic variability and evolution to occur.

random dispersion

Random spacing of individuals of the same species within an area.

p680

Reaction center chlorophyll in the photosystem II.

p700

Reaction center cholophyll in the photosystem I.

endergonic reaction

Reaction that absorbs free energy from its surroundings.

exergonic reaction

Reaction that proceeds with a net release of free energy.

hydrolysis

Reaction where water split into two hydrogens and one oxygen; this breaks a polymer.

reading frame

Reading mRNA nucleotides in the correct groupings.

Receptor proteins

Receptor proteins are membrane proteins that serve as docking sites for proteins of the extracellular matrix or hormones.

Receptor-mediated endocytosis

Receptor-mediated endocytosis involves cell surface receptors that are covered in clathrin-coated pits. When a particle bind to one of these receptors, the ligand is brought into the cell by the folding in of the cell membrane, forming a vesicle.

coevolution

Reciprocal evolutionary adaptations of two interacting species.

Recognition and adhesion proteins

Recognition and adhesion proteins, such as glycoproteins, are exposed on the extracellular surface and play a role in cell recognition and adhesion

competitive inhibitors

Reduce the productivity of enzymes by blocking substrates from entering active sites.

vasoconstriction

Reduces blood flow and heat transfer by decreasing the diameter of superficial blood vessels.

human disturbance

Reduces species diversity in all communities.

Rh factor

Refers to the presence or absence of the Rh antigen on red blood cells.

midbrain

Region between the hindbrain and the forebrain; it is important for hearing and sight.

operator

Region of DNA that controls RNA polymerase's access to a set of genes with related functions.

recticular formation

Registers and controls activity level, increases excitement, and helps generate sleep.

growth factors

Regulatory proteins that ensure that the events of cell division occur in the proper sequence and at the correct rate.

disulphide bridges

Reinforce tertiary structure.

age structure

Relative number of individuals at each age.

migration

Relatively long-distance movement of individuals, usually on a seasonal basis.

telomeres

Repeated DNA sequences at the ends of eukaryotic chromosomes.

iteroparity

Repeated reproduction.

genome project

Research and technology development effort aimed at mapping and sequencing some or all of the genome of human beings and other organisms

antibiotic resistance

Resistance evolving rapidly in many species of prokaryotes due to overuse of antibiotics, especially in agriculture.

tertiary structure

Results from interactions between side chains.

quaternary structure

Results from two or more polypeptide subunits.

repolarization

Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.

Ribosomes

Ribosomes are organelles that are the sites of protein synthesis - they manufacture all the proteins required by the cell or secreted by the cell. Ribosomes are round structures composed of RNA and proteins and can be either free floating or attached to the endoplasmic reticulum.

bacilli

Rod-shaped bacteria.

Saltatory conduction

Saltatory conduction is the form of conduction of an impulse involving myelin sheaths. In this form the impulse can jump form node to node, instead of the standard "domino effect," therefore speeding up the impulse.

isomers

Same atoms but different arrangement.

homologous structures

Same structure, different function. Comes from common ancestor.

Schwann cells

Schwann cells are cells that wrap around the neuron and produce a substance called the myelin sheath, which insulates the axon.

bionomial nomenclature

Scientific name.

genetics

Scientific study of heredity and variation.

turnover

Seasonal changes in warm and cool water layers in lakes.

specific epithet

Second part of scientific name.

Secondary succession

Secondary succession occurs when a new community develops where another community has been destroyed or disrupted, such as by fire. In this succession, the first organisms are usually not lichens but grasses, shrubs, saplings, and weeds.

immunoglobulins

Secreted antibodies.

Seminiferous tubules

Seminiferous tubes are the main tissues of the testes and are where spermatogonia undergo meiosis.

Sensory neurons

Sensory neurons receive impulses from the environment and bring them to the body. For example, they can be stimulated by touch.

serial endosymbiosis

Sequence of endosymbiotic events that led to an ancestral eukaryote.

cell cycle

Series of events that cells go through as they grow and divide.

eutrophication

Sewage and fertilizer runoff adds nutrients to lakes; phytoplankton decreases and cyanobacteria increases.

mesenteries

Sheets of connective tissue in moist or fluid-filled body cavities.

stabilizing selection

Shift that favors the mean.

directional selection

Shift toward a favorable variation.

disruptive selection

Shift toward the extremes.

Side chain

Side chain is another name for an R group, and is a group of atoms attached to the main part of a molecule and having a ring or chain structure.

paracrine signaling

Signal released from a cell has an effect on neighboring cells.

communication

Signals among animals that include sounds, odors, visual displays, and touches that produce responses.

homology

Similarity resulting from common ancestry.

Simple diffusion

Simple diffusion, or passive transport, refers to the movement of substance down the concentration gradient, which uses no energy.

simple epithelium

Single layer of cells.

ribosomal P site

Site that holds tRNA carrying the growing polypeptide chain.

ribosomal A site

Site that holds the tRNA carrying the next amino acid to be added to the chain.

Ribosomal E site

Site where discharged tRNAs leave the ribosome.

origins of replication

Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides.

Okazaki fragments

Small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand.

vesicle

Small membrane-bound sac that functions in moving products into, out of, and within a cell.

plasmids

Small rings of DNA found naturally in some bacterial cells in addition to the main bacterial chromosome. Can contain genes for antibiotic resistance, or other "contingency" functions.

epitope

Small, accessible portion of an antigen that can be recognized.

nucleolus

Small, dense region within most nuclei in which the assembly of proteins begins.

second messengers

Small, non-protein water soluble molecules or ions that send messages throughout the cells by diffusion.

solute

Something dissolved in a solution.

anticodon

Specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule.

endocrine signaling

Specialized cells release hormone molecules into vessels of the circulatory system, by which they travel to target cells in other parts of the body.

primary electron acceptor

Specialized molecule that shares a reaction center with the chlorophyll a molecule in the light reaction. traps high energy electron before it can return to ground state in the chlorophyll.

Speciation

Speciation refers to the emergence of anew species by evolution.

sympatric speciation

Speciation without a divided population.

interspecific competition

Species compete for a limiting resource. (-/-)

equatorial-polar gradients

Species diversity highest at equator, decreases toward poles.

invasive species

Species generally introduced by humans, that take hold outside of their native range.

biological species concept

Species is a group of populations whose members have the potential to produce fertile offspring.

Batesian mimicry

Species mimics the appearance of an unpalatable or harmful.

outgroups

Species or group of species closely related to the ingroup.

dominant species

Species that are the most abundant or have the most biomass.

big-bang reproduction

Species that have only a single reproductive opportunity, such as agave and salmon.

endangered species

Species that is in danger of extinction throughout all or a significant portion of its range.

threatened species

Species that is likely to become endangered.

repeated reproduction

Species that reproduce over and over.

Sperm cells

Sperm cells are produced by the testes when they are stimulated by testosterone.

cocci

Spherical bacteria.

spirilla

Spiral bacteria.

mesophyll

Spongy tissue in the interior of the leaf where most chloroplasts are found.

Golgi apparatus

Stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum.

granum

Stack of thylakoids.

turnover time

Standing crop biomass compared to production.

Starch

Starch is a polysaccharide of alpha glucose molecules bound together and is produced by most green plants as an energy store.

totipotent

Stem cells with the potential to differentiate into any type of cell.

allopolyploid

Sterile hybrid is changed to a fertile polyploid due to mutation; fertile with each other, but not parent species.

reduced hybrid fertility

Sterile hybrids due to uneven chromosome number.

cholesterol

Steroid common in cell membranes, also in many hormones.

Steriods

Steroids are a class of lipids that have a basic structure of four linked carbon rings and include cholesterol, vitamin D, and a variety of hormones.

starch

Storage polysaccharide of plants.

polyribosomes

Strings of ribosomes that work together to translate a RNA message.

competitive exclusion

Strong competition can lead to local elimination of one of the species.

cell wall

Strong layer around the cell membrane in plants, algae, and some bacteria.

neuron

Structural and functional unit of nervous system.

fluid mosaic model

Structural model of the plasma membrane where molecules are free to move sideways within a lipid bilayer.

organelles

Structures specialized to perform distinct processes within a cell.

enantiomers

Structures that are like a mirror-image.

population genetics

Study of allele frequency distribution and change under the influence of evolutionary processes.

reproductive rates

Study of females to determine reproductive output and how it varies with age of female.

ecology

Study of interactions between organisms and the environment.

physiology

Study of the functions an organism performs.

anatomy

Study of the structure of an organism.

demography

Study of vital statistics of a population and how they change over time.

Substrates

Substrates are the molecules targeted by an enzyme in an enzymatic reaction

primary succession

Succession that begins in a virtually lifeless area.

secondary succession

Succession when an existing community has been cleared, but soil left intact.

-in

Suffix of a protein.

-ose

Suffix of a sugar.

ecological niche

Sum total of a species' use of the biotic and abiotic resources.

niche

Sum total of a species' use of the biotic and abiotic resources; an organism's "role".

estivation

Summer torpor. Enables animals to survive long periods of high temperatures and scarce water supplies.

Surface tension

Surface tension is a property of water, due to the cohesiveness of its molecules, that allows things (sometimes organisms) to float and stride on its surface without sinking.

Sympatric speciation

Sympatric speciation refers to speciation that does not involve geographic barriers, and is common in plants.

transcription

Synthesis of an RNA molecule from a DNA template.

smooth ER

Synthesis of lipids, phospholipids and steroid sex hormones-help detoxify drugs and poisons (liver cells).

cytotoxic T cells or "killer T cells"

T cells that directly attack infecting organisms; these cells attack antigen labeled foreign or host tissue.

T-lymphocytes

T-lymphocytes are cells that fight infection and help the B-lymphocytes proliferate.

Target cells

Target cells are the specific cells that a hormone effects.

autosomal recessive disorders

Tay-Sachs, Cystic fibrosis, sickle cell anemia, phenylketonuria

biomanipulation

Technique for restoring eutrophic lakes that reduces populations of algae by manipulating higher-level consumers.

character displacement

Tendency of characteristics to be more divergent in sympatric populations than allopatric populations.

Green World Hypothesis

Terrestrial herbivores consume relatively little plant biomass because they are held in check by predators, parasites and disease.

Testosterone

Testosterone is a male sex hormone responsible for promoting spermatogenesis. Testosterone also maintains secondary sex characteristics.

cerebellum

The "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance.

circadian rhythms

The 24-hour biological cycles found in humans and many other species.

5' cap

The 5' end of a pre-mRNA molecule modified by the addition of a cap of guanine nucleotide.

ATP synthase

The ATP synthase is a channel on the inner mitochondrial membrane. Protons diffuse through the ATP synthase channel, moving into the matrix of the mitochondria. The ATP synthase uses the energy from this diffusion to combine ADP and P on the matrix side of the channel, creating ATP, a process known as oxidative phosphorylation. The total number of ATP produced by oxidative phosphorylation is 32 ATP.

template strand

The DNA strand that provides the template for ordering the sequence of nucleotides in an mRNA transcript.

Hardy-Weinberg law

The Hardy-Weinberg law states that even with all the shuffling of genes that goes on, the relative frequencies of genotypes in a population still prevail over time; the dominant gene doesn't become more prevalent and the recessive gene doesn't disappear. The Hardy-Weinberg law only applies if a population meets five conditions: large population, no mutations, no immigration or emigration, random mating, and no natural selection.

Krebs cycle (citric acid cycle)

The Krebs Cycle, also known as the citric acid cycle, takes place in the matrix of the mitochondria. In the Krebs Cycle, each of the two acetyl coenzyme A molecules enter the cycle and combine with oxaloacetate to form citric acid, which then loses two carbons as carbon dioxide. The cycle is now ready to begin again with the second Acetyl CoA. For each Acetyl CoA, the Krebs Cycle produces 1 ATP, 3 NADH, and 1 FADH2.

Major histocompatibility complex

The MHC is a set of cell surface proteins essential for acquired immune system to recognize foreign cells.

Microtubule Organizing Centers (MTOCs)

The MTOC is a structure found in eukaryotic cells from which microtubules emerge. MTOCs have two main functions: the organization of eukaryotic cilia and flagella, and the organization of the mitotic and meiotic spindle apparatus.

Nodes of Ranvier

The Nodes of Ranvier are the spaces between myelin sheaths - the exposed regions of the axon.

self-incompatibility

The ability of a seed plant to reject its own pollen and sometimes the pollen of closely related individuals.

tonicity

The ability of a solution to cause a cell to gain or lose water; depends partly on concentration of nonpenetrating solutes relative to inside of cell.

cognition

The ability of an animal's nervous system to perceive, store, process, and use information gathered by sensory receptors.

associative learning

The ability of animals to associate one feature with another.

Active site

The active site is a region on the enzyme where the substrate binds.

DNA methylation

The addition of methyl groups to bases of DNA after DNA synthesis; may serve as a long-term control of gene expression.

Adrenal cortex

The adrenal cortex is an endocrine gland that is part of the adrenal glands. The adrenal cortex is targeted by adrenocorticotropic hormone (ACTH), which stimulates the adrenal cortex to produce and secrete its different hormones. The adrenal cortex releases two types of hormones: glucocorticoids, to lower blood sugar, and mineralocorticoids, to help the body retain sodium and water in the kidneys.

Allantois

The allantois is an extra-embryonic membrane that is involved in gas exchange and stores uric acid.

alteration of generations

The alteration of two or more different forms in the life cycle of a plant or animal.

Amnion

The amnion is an extra-embryonic membrane that forms a fluid-filled sac that protects the embryo.

critical load

The amount of added nutrient that can be absorbed by plants without damaging ecosystem.

activation energy

The amount of energy needed to push the reactants over an energy barrier.

glucagon

The antagonist of insulin that helps increase blood sugar. It stimulates the liver to break down glycogen into glucose.

Anterior pituitary

The anterior pituitary is a part of the pituitary gland that secretes six hormones, three of which regulate growth and other organs and three of which are involved in regulating the reproductive system. The hormones of the anterior pituitary are growth hormone, adrenocorticotropic hormone, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, and prolactin.

B cell receptor

The antigen receptor on B cells: a Y-Shaped, membrane-bound molecule consisting of two identical heavy chains and two identical light chains linked by disulfide bridges and containing two antigen-binding sites.

density dependent inhibition

The arrest of cell division that occurs when cells grown in a laboratory dish touch one another.

transcription initiation complex

The assembly of transcription factors and RNA polymerase.

Chemical bond

The atoms of a compound are held together by chemical bonds, which may be ionic bonds, covalent bonds, or hydrogen bonds.

histone acetylation

The attachment of acetyl groups to certain amino acids of histone proteins.

Autonomic nervous system

The autonomic nervous system is the part of the peripheral nervous system that controls involuntary activities, such as the digestive system or heartbeats.

Axon bulb

The axon bulb is the area at the end of the axon, where signal transmission to the next neutron occurs.

Axon

The axon is a long, slender extension that transmits an impulse from the cel body to another neuron or to an organ.

receptacle

The base of a flower; the part of the stem that is the site of attachment of the floral organs.

transduction

The binding of the signal molecule changes the receptor protein in some way.

Blastocoel

The blasocoel is the fluid filled cavity inside a blastula.

humoral immune response

The branch of acquired immunity that involves the activation of B cells and that leads to the production of antibodies, which defend against bacteria and viruses in body fluids.

cell-mediated immune response

The branch of acquired immunity that involves the activation of cytotoxic T cells, which defend against infected cells.

Cell body

The cell body is a part of a neuron that contains the nucleus and other organelles found in the cytoplasm.

Cells

The cell is the basic unit of structure of function in life and is what all living things are composed of.

Central nervous system

The central nervous system includes all of the neurons within the brain and spinal cord.

Cerebellum

The cerebellum is a part of the brain that coordinates muscle activity and refinement of movement.

Cerebral cortex

The cerebral cortex is outer gray matter of the cerebrum that plays an important role in consciousness.

Cerebrum

The cerebrum is a part of the brain that controls all voluntary activities and receives and interprets sensory information. It is the largest part of the brain and consists of outer gray matter (cerebral cortex) and inner white matter.

de-etiolation

The changes a plant shoot undergoes in response to sunlight; also known informally as greening.

Chorion

The chorion is the outermost extra-embryonic membrane that surrounds all the other extra-embryonic membranes.

Climax community

The climax community is the final community in ecological succession. THis community is the most sable and often includes deciduous trees.

therapeutic cloning

The cloning of human cells by nuclear transplantation for therapeutic purposes, such as the generation of embryonic stem cells to treat disease.

electrochemical gradient

The combination of forces that acts on membrane potential.

chromatin

The complex of DNA and proteins that makes up a eukaryotic chromosome.

osmoregulation

The control of water balance.

Corpus callosum

The corpus callosum is a thick band of nerve fibers of the white matter that enable the right and left side of the cerebral hemispheres to communicate.

cotransport

The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.

hybridization

The crossing of two true-breeding parents.

Cytoskeleton

The cytoskeleton is a network of fibers that holds the cell together and enables it to keep its shape. These fibers include microtubules and microfilaments.

immunization

The deliberate exposure of a pathogen to produce memory cells.

pattern formation

The development of a spatial organization of tissues and organs.

dialysis

The diffusion of small solutes through a selectively permeable membrane.

osmosis

The diffusion of water through a selectively permeable membrane.

genetic engineering

The direct manipulation of genes for practical purposes.

Endoplasmic reticulum (ER)

The endoplasmic reticulum is a continuos channel that extends into many regions of the cytoplasm. The rough ER contains many ribosomes on its surface and generates proteins, which are then trafficked to or across the plasma membrane. The smooth ER lacks ribosomes and makes lipids, hormones, and steroids, and breaks down toxic chemicals.

pH gradient (proton gradient)

The energy released from the electron transport chain is used to pump hydrogen ions across the inner mitochondrial membrane to the inter-membrane space. The pumping of hydrogen ions into the inter-membrane space creates a pH gradient, in which the inter-membrane space has a high hydrogen concentration and the matrix has a low hydrogen concentration. This gradient establishes the potential energy responsible for the production of ATP, as hydrogen molecules diffuse through the ATP synthase.

Sere

The entire sequence of ecological succession is known as a sere.

ATP synthase

The enzyme that make ATP from ADPand inorganic phosphate.

protein kinase

The enzyme that transfers phosphate groups from ATP to protein.

Epididymis

The epididymis is a highly convoluted duct behind the testis, where the spermatids mature and then pass to the van deferens.

differential gene expression

The expression of different sets of genes by cells with the same genome.

Fallopian tube

The fallopian tubes are a part of the female reproductive system to which the ovum travels during ovulation and are the site of fertilization. They are also known as oviducts.

G1 phase

The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

First law of thermodynamics

The first law of thermodynamics states that energy cannot be created or destroyed.

cleavage furrow

The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.

pioneer species

The first species that colonize new area, such as lichen and mosses.

"Flight-or-fight" response

The flight-or-fight response is a response that occurs when an organism confronted with a threatening situation prepares to fight or flee. This response is controlled by the sympathetic system. This response includes rising heart and respiration rates, constriction of blood vessels, increase in the levels of glucose in your body, and "goose bumps" on your skin.

stroma

The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.

Fluid-mosaic model

The fluid-mosaic model refers to the arrangement of phospholipids and proteins in the plasma membrane of cells.

Follicular phase

The follicular phase is a phase in the menstrual cycle during which FSH stimulates the growth of follicles in the ovary, one of which will dominate the others and eventually be the only one growing. During this phase, the growing follicle releases estrogen, which leads to a surge of LH, which triggers ovulation, making the follicle burst and release the ovum into the fallopian tube. The follicular phase also involves the thickening of the uterine walls in preparation for the implantation of a fertilized cell. This entire phase lasts about 10 days.

production efficiency

The fraction of energy stored in food that was not used for cell respiration.

restriction fragment

The fragment of DNA that is produced by cleaving DNA with a restriction enzyme.

intercellular joining

The function of membrane proteins in which membrane proteins of adjacent cells hook together, as in gap junctions or tight junctions.

cell-cell recognition

The function of membrane proteins in which some glycoproteins serve as ID tags that are recognized by membrane proteins of other cells.

Genetic variability

The genetic differences in every individual is known as genetic variability. The survival of a species is dependent on genetic variation, since it allows a population to survive in a changing environment.

F1 Generation

The hybrid offspring of true-breeding parents.

Hypothalamus

The hypothalamus is a part of the brain that works closely with the pituitary, regulating the anterior pituitary by secreting neurohormones that can stimulate or inhibit the actions of the anterior pituitary.

Hypothalamus

The hypothalamus is the part of the brain that regulate homeostasis, secretes hormones, and regulates the pituitary gland.

Immune system

The immune system is one of the body's defense systems - a carefully coordinated system of specialized cells to protect the body from foreign threats.

HIV (human immunodeficiency virus)

The infectious agent that causes AIDS. HIV is a retrovirus.

carbon fixation

The initial incorporation of carbon into organic compounds.

primary transcript

The initial mRNA transcript that is transcribed from a protein coding gene. Also called pre-mRNA.

Inner mitochondrial membrane

The inner mitochondrial membrane is the innermost membrane of the mitochondria. Oxidative phosphorylation and chemiosmosis take place at the inner mitochondrial membrane, which produces ATP via the flow of protons across the membrane.

Inter-membrane space

The inter-membrane space is the space between the inner and outer mitochondrial membrane. In cellular respiration, hydrogen atoms are pumped across the inner mitochondrial membrane into the inter-membrane space, creating a proton gradient that is responsible for the production of ATP.

Islets of Langerhans

The islets of Langerhans are clusters of cells in the pancreas that produce insulin and glucagon. The alpha cells produce glucagon and the beta cells produce insulin.

synapse

The junction between two neurons or between a neuron and a muscle.

species-area curve

The larger the geographic area, the greater the number of species.

forebrain

The largest and most complicated region of the brain, including the thalamus, hypothalamus, limbic system, and cerebrum.

host range

The limited range of host cells that each type of virus can infect and parasitize.

Ester linkage

The linkage formed between the glycerol molecule and the fatty acids in a fat is the ester linkage. This bond is formed through dehydration synthesis.

reaction center

The location of the first light driven chemical reaction of photosynthesis.

Lymphatic system

The lymphatic system is a system in the body made up of a network of vessels that conduct lymph. The lymphatic system has three functions: to collect, filter, and return fluid to the blood by the contraction of adjacent muscles, to fight infection using lymphocytes, and to remove excess fluid from body tissue.

leaf

The major sites of photosynthesis in most plants.

biotechnology

The manipulation of living organisms or their components to produce useful products.

Matrix

The matrix is the inner region of the mitochondria, inside the inner membrane. The citric acid cycle, or Krebs cycle, takes place inside the matrix of the mitochondria.

Medulla

The medulla is the part of the brain that controls involuntary actions such as breathing, swallowing heartbeat, and respiration.

plasma membrane

The membrane at the boundary of every cell that acts as a selective barrier, thereby regulating the cell's chemical composition.

resting potential

The membrane potential of a neuron that is at rest.

phosphorylation

The metabolic process of introducing a phosphate group into an organic molecule.

basal metabolic rate (BMR)

The metabolic rate of a nongrowing, resting, fasting, nonstressed endotherm.

standard metabolic rate (SMR)

The metabolic rate of a resting, fasting, nonstressed ectotherm.

Midbrain

The midbrain is the center for visual and auditory reflexes (pupil reflex and blinking).

threshold potential

The minimum membrane potential that must be reached in order for an action potential to be generated.

Mitochondria

The mitochondria is an organelle that converts the energy from organic molecules into useful energy for the cell through cellular respiration.

spatial learning

The modification of behavior based on experience with the spatial structure of the environment.

learning

The modification of behavior based on specific experiences.

RNA processing

The modification of mRNA before it leaves the nucleus that is unique to eukaryotes.

positional information

The molecular cues that control pattern formation.

rubisco

The most abundant protein on earth. Performs Carbon Fixation in the Calvin Cycle.

Acquired Immunodeficiency Syndrome (AIDS)

The most advanced, and fatal, stage of an HIV infection.

glutamate

The most common neurotransmitter in the brain. Excitatory.

clumped dispersion

The most common pattern of dispersion; individuals aggregated in patches.

cytoplasmic streaming

The motion of cytoplasm in a cell that results in a coordinated movement of the cell's contents.

P generation

The name for the true-breeding parents.

synaptic cleft

The narrow gap that separates the presynaptic neuron from the postsynaptic cell.

Nerve net

The nerve net is a system made up of a network of nerve cells, the impulse of which travels in both directions. The nerve net is the simplest nervous system found in simple animals such as hydra.

Neutral tube

The neural tube cells are cells formed during the neurula stage that develop into the central nervous system.

postsynaptic cell

The neuron, muscle, or gland cell that receives the signal from a neuron.

Neurula

The neurula stage of embryo development begins with the formation of the notochord and the neural tube cells, which are part of the development of a nervous system.

leading strand

The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' to 3' direction.

realized niche

The niche species actually occupies.

fundamental niche

The niche species could potentially occupy.

Notochord

The notochord is a rod shaped structure running beneath the nerve cord that is formed during the neurula stage and is important in the development of the nervous system.

Nucleoid

The nucleoid is the area in a prokaryotic cell in which the circular DNA molecule lies free in the cell.

Nucleolus

The nucleolus is the most visible structure within a cell's nucleus and is where rRNA is made and ribosomes are assembled.

Nucleus

The nucleus is the positively charged core in an atom made up of neutrons and protons.

brainstem

The oldest part and central core of the brain, responsible for automatic survival functions.

ethylene

The only gaseous plant hormone. Among its many effects are response to mechanical stress, programmed cell death, leaf abscission, and fruit ripening.

genome

The ordering of genes in a haploid set of chromosomes of a particular organism.

mitochondria

The organelles in which nutrients are converted to energy.

Outer membrane

The outer membrane is the outermost membrane in the mitochondria that protects and holds the form of the organelle.

carpel

The ovule-producing reproductive organ of a flower, consisting of the stigma, style, and ovary.

pH scale

The pH scale is a logarithmic scale to measure acidity, with 1 being most acidic, 14 being most basic, and 7 being neutral.

Parathyroids

The parathyroids are four little pea-shaped organs that rest on the thyroid. They secrete parathyroid hormone, which increases blood calcium levels.

hypocotyl

The part of a plant embryo directly below the cotyledons, forming a connection with the radicle.

sympathetic division

The part of the autonomic nervous system that arouses the body to deal with perceived threats.

autonomic nervous system

The part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands.

uniform dispersion

The pattern in which individuals are equally spaced throughout a habitat.

Peripheral nervous system

The peripheral nervous system includes al neurons lying outside the brain and the spinal cord - in our skin, our organs, and our blood vessels.

Phospholipid bilayer

The phospholipid bilayer is the double layered plasma membrane that surround cells.

water potential

The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure.

Pituitary

The pituitary land is called the master gland because it releases many hormones that reach other glands and stimulate them to release their own hormones. The pituitary gland has two parts: the anterior pituitary and the posterior pituitary.

Placenta

The placenta is an outgrowth of extra-embryonic membranes in placental mammals that is the organ that provides the fetus with nutrients and oxygen and gets rid of the fetus's waste. The placenta develops from both the chorion and the uterine tissue of the mother.

Plasma membrane

The plasma membrane is a double layered structure made up of phospholipids and proteins that serves as an outer envelope for cells. In the membrane, hydrophobic fatty acid tails face inwards and hydrophilic phosphate heads face outwards. The membrane is semi-permeable and regulated the movement of substances in and out of the cell.

F plasmid

The plasmid form of the F factor.

determination

The point during development at which a cell becomes committed to a particular fate due to cytoplasmic effects or to induction by neighboring cells.

stamen

The pollen-producing reproductive organ of a flower, consisting of an anther and a filament.

Pons

The pons connects parts of the brain with one another and contains respiratory center.

grey matter

The portions of the central nervous system that are abundant in cell bodies of neurons rather than axons. Unmyelinated.

Posterior pituitary

The posterior pituitary is a part of the pituitary gland that secretes two hormones: antidiuretic hormone and oxytocin.

hindbrain

The posterior portion of the brain including cerebellum and brainstem.

one gene-one polypeptide hypothesis

The premise that a gene is a segment of DNA that codes for one polypeptide.

turgor pressure

The pressure inside of a cell as a cell pushes itself against the cell wall.

signal transduction pathway

The process by which a signal on a cell's surface is converted into a specific cellular response.

antigen presentation

The process by which an MHC molecule binds to a fragment of an intracellular protein antigen and carries it to the cell surface, where it is displayed and can be recognized by a T cell.

morphogenesis

The process by which an organism takes shape and the differentiated cells occupy their appropriate locations.

induction

The process by which neighboring cells can influence the determination of a cell.

depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

cell division

The process in reproduction and growth by which a cell divides to form daughter cells.

cleavage

The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically.

Primary succession

The process of ecological succession in which no previous organisms have existed is called primary succession. For example, rock previously hidden under a glacier would undergo primary succession upon exposure. In primary succession, lichen first colonize an area and make it more habitable. Lichen are then replaced by mosses and ferns, which are replaced by tough grasses, then low shrubs, then evergreen trees, and finally, deciduous trees.

gene cloning

The production of multiple copies of a gene.

relative abundance

The proportion of each species.

capsid

The protein shell that encloses a viral genome. It may be rod-shaped, polyhedral, or more complex in shape.

peripheral proteins

The proteins of a membrane that are not embedded in the lipid bilayer; they are appendages loosely bound to the surface of the membrane.

independent assortment

The random distribution of the pairs of genes on different chromosomes to the gametes.

chromatin

The readily stainable substance of a cell nucleus consisting of DNA and RNA and various proteins.

Refractory period

The refractory period is the period after an action potential. During this period, sodium channels are reset and are able to open, but the cell membrane potential is further from the threshold and a great stimulus is required to reach the threshold.

cytoplasm

The region of the cell between the cell membrane and the nucleus.

centromere

The region of the chromosome that holds the two sister chromatids together during mitosis.

genetic recombination

The regrouping of genes in an offspring that results in a genetic makeup that is different from that of the parents.

testcross

The result of breeding a recessive homozygote with an organism of dominant phenotype but unknown genotype.

cerebral hemispheres

The right and left halves of the cerebrum.

ethology

The scientific study of how animals behave, particularly in natural environments.

G2 phase

The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

Second law of thermodynamics

The second law of thermodynamics states that energy transfer leads to less organization and the universe tends towards disorder (entropy).

hormone

The secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect.

Peripheral Nervous System (PNS)

The sensory and motor neurons that connect the CNS to the rest of the body.

gel electrophoresis

The separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel.

Molecular biology

The similarities of organisms at the molecular level is compelling evidence of evolution. Scientists have observed that organisms that are closely related have a greater proportion of DNA sequence sin common than distantly related species.

insertion sequence

The simplest kind of transposable element, consisting of inverted repeats of DNA flanking a gene for transposase, the enzyme that catalyzes transposition.

population density

The size of the population within a particular unit of space.

Sodium-potassium pump

The sodium-potassium pump is a channel protein that ushers out sodium ions and brings in potassium ions across the cell membrane, and depend on ATP to get ions across. This pump is found in neurons and skeletal muscle fibers.

cytosol

The soluble portion of the cytoplasm, which includes molecules and small particles, such as ribosomes, but not the organelles covered with membranes.

Somatic nervous system

The somatic nervous system is the part of the peripheral nervous system that controls voluntary activities.

locus

The specific site of a particular gene on its chromosome.

gametophyte

The stage in the life cycle of a plant in which the plant produces gametes, or sex cells.

style

The stalk of a flower's carpel, with the ovary at the base and the stigma at the top.

stigma

The sticky part of a flower's carpel, which receives pollen grain.

bioenergenetics

The study of how organisms manage their energy resources.

biosphere

The sum of all ecosystems.

Sympathetic nervous system

The sympathetic nervous system is a part of the autonomic system that controls the "flight-or-fight" response in organisms.

Synapse

The synapse is the space between two neurons where the neurotransmitter is diffused across.

translation

The synthesis of a polypeptide, which occurs under the direction of mRNA.

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

endocrine system

The system of glands that produce endocrine secretions that help to control bodily metabolic activity.

reception

The target cell's detection of a signal molecule coming from outside the cell.

Thalamus

The thalamus is the main sensory relay center for conducting information between the spinal cord and cerebrum.

sliding filament model

The theory explaining how muscle contracts, based on change within a sarcomere, the basic unit of muscle organization, stating that thin (actin) filaments slide across thick (myosin) filaments, shortening the sarcomere; the shortening of all sarcomeres in a myofibril shortens the entire myofibril

Threshold

The threshold is the minimum amount of stimulus a neuron needs to respond.

Thyroid gland

The thyroid gland, which is located in the neck, is the target organ of the thyroid-stimulating hormone (TSH). When the thyroid is stimulated by TSH, it releases the hormone thyroxine, which is responsible for regulating the metabolic rates in body tissue.

inclusive fitness

The total effect an individual has on proliferating its genes by producing its own offspring and by providing aid that enables other close relatives to increase the production of their offspring.

response

The transduced signal finally triggers a specific cellular response.

presynaptic cell

The transmitting neuron in a synapse.

Umbilical chord

The umbilical chord is an organ that is an outgrowth of extra-embryonic membranes in placental mammals and connects the embryo to the placenta.

energy coupling

The use of an exergonic process to drive an endergonic one.

vernalization

The use of cold treatment to induce a plant to flower.

Uterine wall/ Endometrium

The uterine wall, or endometrium, is the inner mucous membrane of the mammalian uterus. During the follicular phase of the menstrual cycle the endometrium thickens in preparation for the implantation of a fertilized cell. In the luteal phase of the menstrual cycle, progesterone promotes the growth of glands and blood vessels in the endometrium in preparation for pregnancy. If the egg is not fertilized, some of the tissue that the progesterone encouraged to grow on the uterine wall is shed and bled out.

Vas deferens

The vas deferens is the duct that conveys sperm from the testicle to the urethra.

membrane potential

The voltage across a cell's plasma membrane.

membrane potential

The voltage of a plasma membrane.

behavior

The way an organism reacts to changes in its internal condition or external environment.

Yolk sac

The yolk sac is an extra-embryonic membrane that provides food for the embryo.

natural killer (NK) cells

These cells kill cancer cells and cells infected with viruses. They bind to their targets and deliver a lethal burst of chemicals to produce holes in the target cell's membrane leading to its destruction.

local regulators

These regulators influence cells in the vicinity of them.

crenation

This happens when a cell shrinks and shrivels; can result in cell death if severe.

plasmolysis

This happens when a cell shrinks inside its cell wall while the cell wall remains intact.

cytolysis

This happens when a cell swells until pressure bursts it, resulting in cell death.

flaccid

This happens when water moves, but the amount within the cell is constant; no pressure builds.

solute potential

This measurement has a maximum value of 0; it decreases as the concentration of a solute increases.

pressure potential

This measurement has a minimum value of 0 (when the solution is open to the environment); it increases as pressure increases.

chromosomes

Threadlike structures made of DNA molecules that contain the genes.

triplet code

Three-nucleotide long set that specifies a specific amino acid for a polypeptide chain.

Thyroid-stimulating hormone (TSH)

Thyroid-stimulating hormone is a hormone produced in the anterior pituitary that stimulates the thyroid to secrete thyroxine, which is responsible for the regulation of metabolism.

Thyroxine

Thyroxine is a hormone secreted by the thyroid that contain iodine and is responsible for regulating metabolic rates in body tissue.

Tight junctions

Tight junctions are tight connections between the membrane of adjacent animal cells. They're so tight that there is no space between the cells, so they seal off body cavities and prevent leaks.

brown fat

Tissue in neck and between shoulders of some mammals that is specialized for rapid heat production.

muscle tissue

Tissue made of cells capable of contracting.

glandualar epithelia

Tissue that absorbs or secretes chemical solutions.

loose connective tissue

Tissue that binds epithelia to underlying tissues and holds organs in place. Contains collagenous, elastic, and recticular fibers.

epithelial tissue

Tissue that covers outside of the body and lines organs and cavities.

connective tissue

Tissue that functions mainly to bind and support other tissues.

nervous tissue

Tissue that senses stimuli and transmits signals.

adipose tissue

Tissue that stores fat.

organs

Tissues are organized into:, group of tissues that work together to perform closely related functions.

digestion

To break apart.

multiplication rule

To determine the probability, we multiply the probability of one event by the probability of another.

synthesis

To put together.

biomass

Total dry mass of all individuals in a population.

species richness

Total number of different species.

biological magnification

Toxins become more concentrated in successive trophic levels.

Trace elements

Trace elements are elements required by an organism in very small quantities. Trace elements include iron, iodine, and copper.

shared primitive character

Trait shared beyond the taxon.

life history

Traits that affect an organism's schedule of reproduction and survival.

Transmembrane proteins

Transmembrane proteins are integral proteins that do not extend all the way through the membrane.

heredity

Transmission of traits from one generation to the next.

passive transport

Transport of a substance across a cell membrane by diffusion. No cell energy required.

Transport proteins

Transport proteins are membrane proteins that form pumps that use ATP to actively transport solutes across the membrane.

Tubulin

Tubulin is the protein of which microtubules are made up of.

The Law of Segregation

Two alleles separate during gamete formation and end up in different gametes because they are on on homologous chromosomes.

Müllerian mimicry

Two or more unpalatable species resemble each other.

Competitive Exclusion Principle

Two species competing for same limiting resource cannot coexist in one place; one species will have an advantage that will eventually lead to competitive exclusion

semiconservative model

Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand.

Schwann cells

Type of glia in the PNS, Supporting cells of the peripheral nervous system responsible for the formation of myelin.

oligodendrocytes

Type of glial cell in the CNS that wrap axons in a myelin sheath.

ligand-gated ion channel

Type of membrane receptor that has a region that can act as a "gate" when the receptor changes shape.

bottom-up model

Unidirectional influence from lower to higher trophic levels. (V --> H)

fertilization

Union of gametes.

genes

Units of heredity made up of DNA.

stem cell

Unspecialized cell that can both reproduce itself indefinitely and differentiate into specialized cells of one or more types.

bioremediation

Use of living organisms such as prokaryotes, fungi, or plants to detoxify polluted ecosystems.

Gram stain

Used to classify prokaryotes based on cell wall composition. Important for antibiotics; some antibiotics work on one but not the other.

biological augmentation

Uses organisms to add essential materials to degraded ecosystems.

reproductive cloning

Using a somatic cell from a multicellular organism to make one or more genetically identical individuals.

Vacuoles

Vacuoles are fluid-filed sacs that store water, food, wastes, salts, or pigment. They are found in both animal and plant cells, but much larger in plant cells.

genomic imprinting

Variation in phenotype depending on whether an allele is inherited from the male or female parent.

species diversity

Variety of different kinds of organisms that make up a community.

microclimate

Very fine patterns of climate influenced by features of the environment such as shade ares and wind patterns.

Vesicles

Vesicles are little membrane sacs which carry materials around and out of the cell.

transport vesicles

Vesicles in transit from one part of the cell to another.

optimal foraging theory

Views foraging behavior as a compromise between benefits of nutrition and costs of obtaining food.

provirus

Viral DNA that inserts into a host genome.

virulent

Viruses that reproduce only by the lytic cycle.

cohesion

Water molecules sticking to each other.

adhesion

Water molecules sticking to other surfaces.

interstitial fluid

Watery, internal environment of vertebrates.

Aerobic respiration

When ATP is made in the presence of oxygen, the process is called aerobic respiration. Aerobic respiration consists of four stages: Glycolysis, formation of acetyl CoA, the Krebs cycle, and oxidative phosphorylation.

Anaerobic respiration

When ATP is made without oxygen, the process is called anaerobic respiration.

active transport

When a cell gets materials or excretes them by using its own energy, usually through ATP; going against a concentration gradient.

Cyclic AMP (cAMP)

When a hormone binds to a receptor protein on the cell membrane of a target cell, the protein stimulates the production of a second messenger called cyclic AMP. The cAMP molecule then triggers various enzymes, leading to a specific cellular change.

gene flow

When a population gains or loses alleles., movement of alleles into or out of a population due to the migration of individuals to or from the population.

bottleneck effect

When a population has been dramatically reduced, and the gene pool is no longer reflective of the original population's.

allopatric speciation

When a population is divided; leads to speciation.

allosteric regulation

When a protein's function at one site is affected by the binding of a regulatory molecule to a separate site.

founder effect

When a small number of individuals colonize a new area; the new gene pool is not reflective of original population.

diffusion

When a substance moves from an area of higher concentration to an area of lower concentration. Due to entropy.

Zygote

When an egg is fertilized by a sperm, it forms a diploid cell called a zygote. A zygote has 46 chromosomes, while the egg and sperm have 23 each.

enzyme-substrate complex

When an enzyme binds to its substrate, it forms:

substrate-level phosphorylation

When an enzyme transfers a phosphate group from a substrate molecule.

density-dependent regulation

When birth or death rates do change with population density.

density-independent regulation

When birth or death rates do not change with population density.

oxidative phosphorylation

When energy is released at each step of the chain is stored in a form the mitochondrion can use to make ATP.

chemiosmosis

When energy is stored in the form of a hydrogen ion gradient across a membrane which is used to drive cellular work.

nonshivering thermogenesis (NST)

When hormones cause mitochondria to produce heat instead of ATP in some mammals.

logistic growth

When limiting factors restrict size of population to the carrying capacity of the environment. Forms an S-shaped curve.

graft versus host reaction

When lymphocytes in donated bone marrow react against the recipient.

metapopulation

When many populations are linked.

cellular respiration

When oxygen is consumed as a reactant along with the organic fuel.

Acetyl coenzyme A

When oxygen is present, pyruvic acid is transported to the mitochondrion, where each pyruvic acid is converted into acetyl coenzyme A, a two carbon molecule. Two Acetyl CoA are produced from two pyruvic acid. Acetyl CoA then moves to the Krebs Cycle, where it combines with oxaloacetate to form citric acid.

zero population growth (ZPG)

When per capita birth and death rates are equal. (r = 0)

alcohol fermentation

When pyruvate is converted to ethanol in 2 steps.

lactic acid fermetation

When pyruvate is reduced directly by NADH to form lactic as am end product, with no release of carbon dioxide.

gametic isolation

When sperm can't fertilize the eggs.

reduced hybrid viability

When the genes of different species interact and impair hybrid development.

plasmolyze

When the membrane shrinks away from the cell wall as a result of water loss.

complete dominance

When the phenotypes of the heterozygote and dominant homozygote are indistinguishable.

redox reactions

When there is a transfer of one or more electrons from one reactant to another.

Dipeptide

When two amino acids join they form a dipeptide. In a dipeptide, the carboxyl group of one amino acid combines with the amino group of another amino acid.

sexual reproduction

When two parents give unique combination of genes to offspring.

temporal isolation

When two species breed at different times of day, season, or years.

habitat isolation

When two species encounter each other only rarely.

codominance

When which the phenotypes of both alleles are exhibited in the heterozygote.

Seminal vesicles

While in the vas deferens, sperm picks up fluids from the seminal vesicles which provides them with fructose for energy.

Prostate gland

While traveling through the vas deferens, sperm picks up fluids from the prostate gland which provides an alkaline fluid that neutralizes the vagina's acidic fluids.

lymphocytes

White blood cells.

white matter

Whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths.

sex chromosomes

X and Y chromosomes.

chiasmata

X-shaped regions where crossing over occurred.

incomplete dominance

Yy produces a intermediate phenotype between YY and yy

biomes

a broad, regional type of ecosystem characterized by distinctive climate and soil conditions and a distinctive kind of biological community adapted to those conditions

checkpoints

a cell stops growing to make sure it has the nutrients and raw materials to proceed

kinesis

a change in activity or turning rate in response to a stimulus

covalent bond

a chemical bond that involves sharing a pair of electrons between atoms in a molecule

hydrolysis

a chemical process in which a compound is broken down and changed into other compounds by taking up the elements of water

cancer

a disease in which abnormal cells multiply out of control, spread into surrounding tissues and other body parts, and disrupt normal functioning of one or more organs

complete flowers

a flower that has all four basic floral organs: sepals, petals, stamens, and carpals

angiosperm

a flowering plant, which forms seeds inside a protective chamber called an ovary

crossover

a form of genetic recombination that occurs during prophase I of meiosis

epistasis

a gene at one locus alters the phenotypic expression of a gene at another locus

linkage map

a genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes

cline

a graded change in a trait along a geographic axis

operon

a group of genes that operate together

community

a group of interdependent organisms inhabiting the same region and interacting with each other

ciliates

a group of protozoans that move by waving tiny, hair-like organelles called cilia

fruit

a mature ovary of a flower that protects dormant seeds and aids in their dispersal

negative feedback

a mechanism of response in which a stimulus initiates reactions that reduce the stimulus

ligand

a molecule that binds specifically to a receptor site of another molecule

phospholipids

a molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail

smooth muscle

a muscle that contracts without conscious control and found in walls of internal organs such as stomach and intestine and bladder and blood vessels (excluding the heart)

action potential

a neural impulse; a brief electrical charge that travels down an axon; the action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane

hypothalamus

a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion

endergonic reaction

a non-spontaneous chemical reaction in which free energy is absorbed from the surroundings

malnourishment

a nutritional imbalance caused by lack of specific dietary components or inability to absorb or utilize essential nutrients

tissue

a part of an organism consisting of an aggregate of cells having a similar structure and function

positive feedback

a physiological control mechanism in which a change in a variable triggers mechanisms that amplify the change

gravitropism

a plant's growth in response to gravity

chemiosmosis

a process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.

meiosis

a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells

pre-zygotic barriers

a reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted

signal transduction pathway

a series of steps linking a mechanical or chemical stimulus to a specific cellular response

pleiotropy

a single gene has multiple effects on an organism

keystone species

a species that influences the survival of many other species in an ecosystem

compound

a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight

vaccine

a substance that stimulates the body to produce chemicals that destroy viruses or bacteria

cladistics

a system of phylogenetic analysis that uses shared and derived characters as the only criteria for grouping taxa

entropy

a thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system

codons

a three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.

adaption

a trait that, if altered, affects the fitness of an organism

aquaporins

a transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane

apoptosis

a type of cell death in which the cell uses specialized cellular machinery to kill itself

club fungi

a type of fungus that bears reproductive sperm externally, on club-shaped structures (basidia) at the tips of hyphae

molds

a type of fungus that consists of chains of cells and appears as a fuzzy mass of thin filaments in culture

insight learning

ability to reason through a problem the first time through with no prior experience

plant hormones

abscisic acid, auxin, cytokinins, ethylene, gibberellins

altruistic behavior

action in which an organism helps another at its own expense

short term memory

activated memory that holds a few items briefly, before information is stored or forgotten

adrenal gland hormones

aldosterone and cortisol

biotic factor

all the living things in an ecosystem

functional groups

amino (NH2), carbonyl (RCOR), carboxyl (COOH), hydroxyl (OH), phosphate (PO4), sulfhydryl (SH)

chordates

an animal phylum that has a notochord, a dorsal hollow nerve cord, and gill slits at some time in its life cycle

adhesion

an attraction between molecules of different substances

reflexes

an automatic and often inborn response to a stimulus that involves a nerve impulse

gastrula

an embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm

telomerase

an enzyme that catalyzes the lengthening of telomeres; the enzyme includes a molecule of RNA that serves as a template for new telomere segments

protein kinase

an enzyme that transfers phosphate groups from ATP to a protein

fibrous root system

anchoring systsem that does not go deep down into the soil

Batesian mimicry

animal that is harmless copies the apperance of an animal that is dangerous

reciprocal altruism

animals behave altruistically toward others who are not relatives

invertebrates

animals without a backbone

primary immune response (humoral immunity)

antigen invader -> B cell meets antigen -> B cell differentiates into the plasma cells and memory cells -> plamsa cells produce anitbodies -> antibodies eliminate antigen

secondary immune response

antigen invader -> memory cells recogize antigen and pump out antibodies much quicker than primary response -> antibodies eliminate antigen

germ layer

any of the 3 layers of cells differentiated in embryos following gastrulation

homeotic genes

any of the genes that control the overall body plan of animals and plants by controlling the developmental fate of groups of cells

nephron

any of the small tubules that are the excretory units of the vertebrate kidney

parthenogenesis

asexual reproduction in which females produce offspring from unfertilized eggs

facilitated diffusion

assisted transport of particles across membrane (no energy input)

ion

atom that has a positive or negative charge

cohesion

attraction between molecules of the same substance

hydrophobic

avoids water molecules

saturated fats

bad for you; animals and some plants have it; solidifies at room temp.

promoter

base sequence that signals start site for transcription

unsaturated fats

better for you, plants have it; liquifies at room temp.

circulatory system

bloodflow= left side of heart -> aorta -> via arteries to organs and muscles -> into vena cava -> right side of heart -> lungs -> left side of heart

mRNA

blueprints for proteins

codominace

both alleles express themselves fully in a Yy individual

mutualism

both organisms reap benefits from the interaction

competition

both species are harmed by the interaction

amygdale

brain region that regulates emotions

hydrolysis

breaks down compounds by adding water

tRNA

brings acids to ribosomes

oncogenes

cancer-causing genes

maltase, lactase, and sucrase

carbohydrate digesting enzymes of the small intestines

enzymes

catalytic proteins that react in an induced-fit fashion with substrates to speed up that rate of reactions by lowering the activation energy

GnRH

causes pituitary to release LH and FSH

thoracic cavity

cavity housing lungs and heart

density-dependent inhibition

cell stops growing when certain density is reached

somatic cell

cell that makes up all of the body tissues and organs, except gametes

sexual selection

certain characters are selected for because they aid in mate acquisition

gene flow

change in allele frequencies as genes move from one population to another

genetic drift

change in allele frequencies because of chance events

mutation

change in allele frequencies due to random genetic change in an allele

kinesis

change in the speed of movement in response to a stimulus; organisms will move faster in bad environments and slower in good environments

plasmodesmata

channels through cell walls that connect the cytoplasms of adjacent cells

vestigil character

character contained by organism that is no longer functionally useful

point mutations

chemical changes in just one base pair of a gene

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

neurotransmitters

chemical messengers that traverse the synaptic gaps between neurons

pheromones

chemicals secreted by animal species that influence the behavior of other animals of the same species

autosomal chromosome

chromosome not involved in gender

homologous chromosomes

chromosomes that are similar in shape, size, and function

cortisol

chronic stress hormone

taxonomy

classification of organisms based upon the presence or absence of shared characterstics: kingdom -> phylum -> class -> order -> family -> genus -> species

deciduous forest

cold winters and warm summers

population

collection of individuals of the same species living in the same geographic region

community

collection of populations of species in a geographic area

protobionts

collections of abiotically produced molecules surrounded by a membrane-like structure

cryptic coloration

colring scheme that allows organism to blend into colors of environment

chemical communication

communication through the use of chemical signals, such as pheramones

audiotory communication

communication through the use of sound, such as the chirping of frogs in the summer

tactile communciation

communication through the use of touch, such as a handshake

visual communication

communication through the visual cues, such as the tail feather displays of peacocks

biosphere

communities and the ecosystems of the planet

ecosystem

community and its environment

vitamins

compounds that help regulate many vital body processes, including the digestion, absorption, and metabolism of other nutrients

isomers

compounds with the same formula but different structure

polyploidy

condition in which individual has higher than normal number of chromosomes sets

agnostic behavior

conflict behavior over access to a resource; often a matter of which aniaml can mount the most threatening display and scare the other into submission

eukaryotic cells

contain a nucleus and other organelles that are bound by membranes

organic compounds

contain carbon; examples include lipids, proteins, and carbs

DNA

contains A, G, C, and T; arranged in double helix of two strands held together by hydrogen bonds

RNA

contains A, G, C, and U; singled stranded

cerebellum

controls coordination and balance

medulla

controls involuntary actions such as breathing

ANS

controls involuntary activities of body

prolactin

controls lactogenesis, decreases secretion of GnRH

SNS

controls skeletal muscles and voluntary actions

aldosterone

controls sodium reabsorption in the excretory system

ADH

controls water absorption in the excretory system

Krebs cycle

conversion 1 pyruvate molecule into 4 NADH, 1 FADH2, 1 ATP, H2O, and CO2; occurs twice for each glucose to yeild double the products above; occurs in the mitochondria

glycolysis

conversion of 1 glucose molecule into 2 pyruvate, 2 ATP, and 2 NADH; occurs in the cytoplasma, and in both aerobic and anaerobic respiration; must have NAD+ to proceed

chemiosmosis

coupling of the movement of electrons down the ETC with the formation of ATP using the driving force provided by the proton gradient; occurs in both cell respiration and photosynthesis to produce ATP

monohybrid cross

cross involving one character (3:1 phenotype ratio)

dihybrid cross

cross involving two different characters (9:3:3:1 phenotype ratio)

source of variation

crossover, 2^n possible gametes that can be formed, random pairing of gametes

migration

cyclic movement of animals over long distances according to the time of year

cyclins and protein kinases

cyclin combines with CDK to form a structure known as MPF that pushes cell into mitosis when enough is present

habituation

decreasing responsiveness with repeated stimulation

territoriality

defense of territory to keep others out

frameshift mutation

deletion or addition of nucleotides; shifts reading frame

chromosomal disorders

deletion, inversions, duplications, and translocations

endothermic

dependent on or capable of the internal generation of heat

prokaryotic

describes a cell that does not have a nucleus or anyother membrane-covered organelles; also called bacteria

taproot system

dicots; system that divides into lateral roots that anchor the plant

geographic variation

differences in the genetic composition of separate populations

restriction fragment length polymorphisms (RFLPs)

differences in the restriction sites on homologous chromosomes that result in different restriction fragment patterns.

variation

differences must exist between individuals

alleles

different forms of a gene

osmosis

diffusion of water through a selectively permeable membrane

digestive system

digestion begins in mouth, continues in the stomach, and completes in the intestine

selection types

directional, stabilizing, disruptive, sexual, and artifical

pathogens

disease producing microorganisms

pandemic

disease that occurs over a wide geographic area and affects a very high proportion of the population

desert

driest land biome

redox

electron transfer reactions

seed

embryo of a living plant that is encased in a protective covering and surrounded by a food supply

apical meristems

embryonic plant tissue in the tips of roots and in the buds of shoots that supplies cells for the plant to grow in length

amygdala

emotion control center

macrophages

engulf bacteria and cellular debris by phagocytosis

ATP synthase

enzyme responsible for using protons to actually produce ATP from ADP

amylase

enzyme that breaks down starches in the diet

restriction enzymes

enzymes that cut DNA at a paticular sequences, creating sticky ends

helicases

enzymes that untwist the double helix at the replication forks

nondisjunction

error in meiosis in which homologous chromosomes fail to separate

nondisjunction

error in which homologous chromosomes do not separate properly

endosymbiotic theory

eukaryotes originated from symbiotic partnership of prokaryotic cells

microevolution

evolution resulting from small specific genetic changes that can lead to a new subspecies

gradualism

evolutionary change is slow and steady process

punctuated equilibria

evolutionary change occurs in rapid bursts separated by large periods of no change

limiting factors

factors that keep population size in check

growth factors

factors then when present, promote growth, and when absent, impede growth

pedigree

family tree used to describe genetic relationships

sustainable agriculture

farming method that preserves long-term productivity of land and minimizes pollution

foraging

feeding behavior of an individual

coelom

fluid-filled body cavity lined with mesoderm

disruptive selection

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

conjugation

form of sexual reproduction in which paramecia and some prokaryotes exchange genetic information

centrioles

found in animal cells eukaryote; part of microtubule separation apparatus that assits cell division in animal cells

peroxisome

found in eukaryotes; breakdown of fatty acids, detoxification of alcohol

lysosome

found in eukaryotes; contains enzymes that digest organic compounds; serves as cell's stomach

nucleus

found in eukaryotes; control center of cell; host for transcription, replication, and DNA

smooth ER

found in eukaryotes; lipid synthesis, detoxification, carbohydrate metabolism; contains no ribosomes on cytoplasmic surface

Golgi

found in eukaryotes; modifies lipids, proteins to secrete or send to plasma membrane; contains ribosomes on cytoplasmic surface

mitochondria

found in eukaryotes; power plant of cell; hosts major energy-producing steps of respiration

cytoskeleton

found in eukaryotes; skeleton of cell; consists of microtubules, microfilaments, and intermediate filaments

rough ER

found in eukaryotes; synthesizes proteins to secrete or send to plasma membrane; contains ribosomes on cytoplasmic surface

chloroplast

found in plant cells eukaryotes; site of photosynthesis in plants

ribosome

found in prokaryotes and eukaryotes; host for protein synthesis; form in nucleolus

plasma membrane

found in prokaryotes and eukaryotes; regulates what substances enter and leave a cell

cell wall

found in prokaryotes and plant cells eukaryotes; protects and shapes the cell

water biomes

freshwater and marine biomes

nephron

functional part of the kidney

sex-linked gene

gene located on the X or Y chromosome

linked genes

genes that lie along the same chromsome and do not follow the law of independent assortment

modes of evolution

genetic drift, gene flow, mutation, natural selection

linkage map

genetic map put together using crossover frequencies

vascular cambium

gives rise to secondary xylem/phloem; runs entire length of plant

endocrine glands

glands of the endocrine system that release hormones into the bloodstream

phospholipids

glycerol + 2 fatty acids + 1 phosphate group; makes up membrane bilayers of cells; hydrophobic interiors and hydrophillic exteriors

fat

glycerol and three fatty acids

aerobic respiration

glycolysis -> krebs cycle -> oxidative phosphorylation -> 36 ATP per glucose molecule

anaerobic respiration (fermentation)

glycolysis -> regenerate NAD+ -> 2 ATP per glucose molecule

survivorship curve

graph showing the number of survivors in different age groups for a particular species

savanna

grasslands, home to herbivores

plant trophisms

gravitropism, phototrophism, thigmotropism

tropical forest

great diversity of species in biomes

ganglia

groups of nerve cell bodies that coordinate incoming and outgoing nerve signals

cell cycle

growth 1 -> synthesis -> growth 2 -> mitosis

cell division control mechanisms

growth factors, checkpoints, density-dependent inhibition, and cyclins and protein kinases

exponential growth

growth of a population that multiplies by a constant factor at constant time intervals

heterozygous

having two different alleles for a trait

character

heritable feature, such as flower color

intermediate inheritance

heterozygous individual shows characterstics unlike either parent

trophic levels

hierarchy of energy levels on a planet

negative feedback

hormone acts to directly, or indirectly, inhibit further release of the hormone of interest

antidiuretic hormone

hormone secreted by the posterior pituitary gland to prevent the kidneys from expelling too much water

positive feedback

horomone acts directly, or indirectly, cause increased secretion of the hormone

artifical selection

human intervention in the form of selective breeding

law of dominance

if two opposite pure-breeding varieties are crossed, all offspring resemble dominant parent

acquired immunity

immunity that the body develops after it overcomes a disease, or through inoculation (such as vaccination)

mitosis

in eukaryotic cells, a process of cell division that forms two new nuclei, each of which has the same number of chromosomes

daily torpor

in small mammals and birds, daily lowering of metabolism that allows them to survive on stored energy

primary growth

increased length of plants (occurs in region of apical meristem)

secondary growth

increased width of plant (occurs in region of lateral meristems)

parathyroid hormone (PTH)

increases blood Ca2+ involved in bone maintenance

glucagon

increases glycogen breakdown

insulin

increases glycogen formation

STH

increases growth

TSH

increases release of thyroid hormone

ACTH

increases secrection of adrenal cortical hormones

biological magnification

increasing concentration of a harmful substance in organisms at higher trophic levels in a food chain or food web

hermaphrodite

individual that has both male and female reproductive organs

prions

infectious protein particles that do not have a genome

law of indendent assortment

inheritance of one trait does not interfere with the inheritance of another trait

noncompetitive inhibition

inhibitor binds elsewhere on the enzyme; alters active site so that the substrate cannot bind

competitve inhibtion

inhibitor resembles substrate and binds to active site

abscisic acid

inhibits cell growth, helps close stomata

imprinting

innate behavior learned during critical period early in life

endometrium

inner lining of the uterus

pancreatic hormones

insulin and glucagon

allopatric speciation

interbreeding stops because some physical barrier splits the population into two

sympatric speciation

interbreeding stops even though no physical barrier prevents it

RNA processing

introns (noncoding) are spliced out, exon (coding) glued together

echinoderms

invertebrates with an internal skeleton and a system of fluid-filled tubes called a water vascular system

progestrone

involved in menstrual cycle and pregnancy

cell-mediated immunity

involves T cells and direct cellular response to an invasion. defense against viruses

hemoglobin

iron-containing protein in red blood cells that transports oxygen from the lungs to the tissues of the body

excretory system

kidneys -> minor and major calyces -> renal pelvis -> bladder via the ureter -> out of the body via the urethra

polymer

large compound formed from combinations of many monomers

vacuole

large in plant cells and small in animal cells; storage vaults of cells

observational learning

learning by watching someone else do it first

taiga

lengthy cold, wet winters; lots of conifers

steriods

lipids whose structures resemble chicken-wire fence. include cholesterol and sex hormones

biotic components

living organisms of ecosystem

symbiosis

living together in mutually helpful association of two dissimilar organisms

pH

logarithmic scale; <7 acidic, 7 neutral, >7 basic (alkaline); 4 is 10 times more acidic than 5

chromatin

long strands of DNA found in the eukaryotic cell nucleus; condense to form chromosomes

habituation

loss of responsiveness to unimportant stimuli or stimuli that provide no feedback

transpiration

loss of water via evaporation through the stomata

generalized transduction

lytic cycle accidently places host DNA into a phage, which is brought to another cell

codons

mRNA base triplets.

estrogen

made in ovaries; increases release of LH; develops female secondary sex characteristics

proteins

made with the help of ribosomes out of amino acids; serve many functions (transport, enzymes, cell signals, receptor molecules, structural components, and channels)

pepsin

main digestive enzyme of the stomach that breaks down proteins

bile salts

major emulsifer of fat

lipase

major fat digesting enzyme of the body

trypsin and chymotrypsin

major protein digesting endopeptidases of the small intestine

rRNA

make of ribosomes

pollen grain

male gametophyte in seed plants

sex determination

males are XY, females are XX

placentals

mammals who have offspring who develop inside placenta (humans)

biotic potential

maximum growth rate for a population

carrying capcity

maximum number of individuals that a population can sustain in a given environment

directional selection

members at one end of a spectrum are selected against, and the population shifts toward that end

epithelium

membranous tissue covering internal organs and other internal surfaces of the body

transformation

modification of a cell or bacterium by the uptake and incorporation of exogenous DNA

pigment

molcule that absorbs light of a particular wavelength (chlorophyll, carotenoid, phycobilins)

inducer

molecule that binds to and inactivates a repressor

polar molecule

molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end

five kingdom system

monera -> Protista -> plantae -> Fungi -> animalia

temperate grasslands

most fertile soil of all biomes

small intestine

most of the digestion and absorption of food occurs in the _________

migration

movement from one place to another

gene flow

movement of alleles into or out of a population due to the migration of individuals to or from the population

transduction

movement of genes from one cell to another by phages, which incorporated by crossover

emigration

movement of individuals out of an area

active transport

movement of substances against concentration gradient (low to high concentrations; requires energy input)

vector

mover of DNA from one source to another

specific immunity

multilayered defense mechanism-- first line of defense: phagocyctes, macrophages, neutrophils, complement; second line of defense: B cells and T cells

vasoconstriction

narrowing of blood vessels

optimal foraging

natural selection favors those who choose foraging strategies that maximize the differential betwen cost and benefits

emergent properties

new properties that emerge with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases

ribosomes

non membrane bounded organelles responsible for protein synthesis

abiotic components

nonliving players in an ecosystem

introduced species

nonnative species that are either intentionally or unintentionally transported to a new habitat

inflammatory response

nonspecific defense against infection, characterized by redness, heat, swelling, and pain

nonspecific immunity

nonspecific prevention of enterance of invaders into the body

bryophyte

nonvascular plant; examples are mosses and their relatives

respiratory pathway

nose/mouth -> pharynx -> larynyx -> trachea -> bronchi -> bronchioles -> alveoli

repetitive DNA

nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome.

DNA replication

occurs in S-phase, semiconservative, built in 5' to 3' direction

primary succession

occurs in area devoid of life that contains no soil

secondary succession

occurs in area that once had stable life but was disturbed by major force fire

alcohol fermentation

occurs in fungi, yeast, and bacteria; causes conversion of pyruvate to ethanol

lactic acid fermentation

occurs in humans and animal muscles; causes conversion of pyruvate -> lactate; causes cramping sensation when oxygen runs low in muscles

operon

on/off switch for transcription, allows for production of genes only when needed

haploid (n)

one copy of each chromosome

lytic cycle

one in which the virus is actively reproducing and kills the host cell

lysogenic cycle

one in which the virus lie dormant within the DNA of the host cell

X inactivation

one of two X chromosomes is randomly inactivated and remains coiled as a Barr body

homeobox

one of various similar homeotic genes that are involved in bodily segmentation during embryonic development

parasitism

one organism benefits at another's expense

commensalism

one organism benefits while the other is unaffected

predation

one species, the predator, hunts the other, the prey

associative learning

one stimulus is associated with another (classical conditioning)

hydrocarbons

organic molecules that are composed of only carbon and hydrogen

carnivore

organism that obtains energy by eating animals

autotrophs

organisms that make their own food

producers

organisms that make their own food

heterotrophs

organisms that must consume other organisms to obtain energy--consmers

Hardy-Weinberg equilibrium

p + q = 1, p2 + 2pq + q2 = 1; evolution is not occuring; the rules for this are no mutations, no gene flow, no genetic drift, no natural selection, and random mating

viruses

parastic infectious agent unable to survive outside the host; can obtain DNA or RNA, or have a viral envelope

sex-linked traits

passed along the X chromosome; more common in males then females

diffusion

passive movement of substances down their concentration gradient (from high to low concentrations)

osmosis

passive movement of water from the side of low solute concentration to the side of high solute concentration

deceptive markings

patterns that cause an animal to appear larger or more dangerous than it really is

dormancy

period of time during which a plant embryo is alive but not growing

tundra

permafrost, cold winters, short shrubs

endocytosis

phagocytosis of particles into cell through the use of vesicles

mutagens

physical and chemical agents that interact with DNA to cause mutations

secondary sex characteristics

physical characteristics that differ men and women

cytokinesis

physical separation of newly formed daughter cells of cell division

epiphyte

plant that is not rooted in soil but instead grows directly on the body of another plant

phototropism

plant's growth in response to light

thigmotropism

plant's growth in response to touch

CAM plants

plants close their stomata during the day, collect CO2 at night, and store the CO2 in the form of acids until it is needed during the day for photosynthesis

C4 plants

plants that have adapted their photosynthetic process to more efficiently handle hot and dry conditions

fluid mosaic model

plasma membrane is selectively permeable phosolipid bilayer with proteins of various lengths and sizes interspersed with cholesterol amoung the phospholipids

parenchyma cells

play a role in storage, secrection, and photosynthesis in cells

mitochondria

powerhouse of the cell, produces energy (ATP) from oxygen and sugar

fixed action pattern

preprogrammed response to a stimulus

photophosphorylation

process by which ATP is made during light reactions

endocytosis

process by which a cell takes in a substance by surrounding it with the cell membrane

greenhouse effect

process by which atmospheric gases trap heat close to Earth's surface and prevent it from escaping into space

natural selection

process by which characters or traits maintained or eliminated in a population based on their contribution to the differential survival and reproductive succes of their "host" organism

natural selection

process by which individuals that are better suited to their environment survive and reproduce most successfully

transcription

process by which mRNA is synthesized on a DNA template

exocytosis

process by which particles are ejected from the cell, similar to movement in a trash chute

photosynthesis

process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches

photosynthesis

process by which plants use the energy from light to generate sugar; occurs in chloroplasts; light reactions (thylakoid), and Calvin cycle (stroma)

RNA splicing

process by which the introns are removed from RNA transcripts and the remaining exons are joined together

translation

process by which the mRNA specified sequence of amino acids is lined up on a ribosome for protein synthesis

convergent evolution

process by which unrelated organisms independently evolve similarities when adapting to similar environments

photolysis

process by which water is split into hydrogen ions and oxygen atoms (light reactions)

sexual reproduction

process in which genetic material from two parents combines and produces offspring that differ genetically from either parent

transcription

process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in mRNA

nitrogen fixation

process of converting nitrogen gas into nitrogen compounds that plants can absorb and use (ammonia)

C4 photosynthesis

process that first converts CO2 into a 4-carbon molcule in the mesophyll cells, converts that product to malate and then shuttles it to the bundle sheath cells, where the malate releases CO2 and rubisco picks it up as if all were normal

fermentation

process that regenerates NAD+ so glycolsis can begin again; occurs in absence of oxygen

cellular respiration

process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

endosymbiosis

process through which early prokaryotic cells are thought to have engulfed other, smaller cells and eventually incorporated them as organelles; these cells evolved into modern-day eukaryotes

physiology

processes and functions of an organism

polymerase chain reaction (PCR)

produces large quanties of sequence in short amount of time

cork cambium

produces protective covering that replaces epidermis during secondary growth

viviparous

producing living young (not eggs)

oxidative phosphorylation

production of large amounts of ATP from NADH and FADH2; occurs in the mitochrondria; requires the presence of oxygen to proceed

sex hormones

progestrone, estrogen, and testosterone

bacteria

prokaryotic cell consists of one double strand circular DNA molecule; reproduce by binary fission

binary fission

prokaryotic cell division; double the DNA, double the size, then split apart

cytokinins

promote cell division, leaf enlargement, slow aging of leaves

dermal tissue

protective outer coating for plants: epidermis

sclerenchyma cells

protects seeds and support the plants

peripheral proteins

protein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer

caspid

protein covering that surrounds a virus

insulin

protein hormone that helps to decrease blood sugar

enzyme

protein that acts as a biological catalyst

repressor

protein that prevents the binding of RNA polymerase to promoter site

integral proteins

proteins implanted within lipid bilayer of plasma membrane

collenchyma cells

provide flexible and mechanical support; found in stems and leaves

mutation

random changes in DNA can introduce new alleles into a population

mutations

random errors in gene replication that lead to a change in the sequence of nucleotides; the source of all genetic diversity

dominance hierarchies

ranking of power amoung the members of a group; subject to change

adaptive radiation

rapid series of speciation events that occur when one or more ancestral species invades a new environment

large intestine

reabsorbs water and packs the indigestible food into feces

exergonic reaction

reaction that gives off energy

endergonic reaction

reaction that requires input of energy

inductive reasoning

reasoning based on observed patterns

taxis

reflex movement toward or away from a stimulus

aldosterone

regulates blood sodium concentration

hypothalamus

regulates hunger, thirst, and temperature

vestigial structures

remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species

gametes

reproductive cells, have only half the number of chromosomes as body cells

photoperiodism

response of a plant to the change in length of days

ethylene

ripens fruit and causes leaves to fall

control elements

segments of noncoding DNA in eukaryotic genes that help regulate transcription by binding to certain proteins.

stabilizing selection

selection for the mean of the population; reduces variation of a population

disruptive selection

selects for the two extremes of the population; selects against the middle

autotroph

self-nourishing organism that is also known as a producer (plants)

life cycles

sequences of events that make up the reproductive cycle of an organism

primary sex characteristics

sexual organs that assist in reproduction

okazaki fragments

short fragments of DNA that are a result of the synthesis of the lagging strand during DNA replication

operator

short sequence near the promoter that assists in transcription by interacting with transcription factors

protists

single-celled or simple multicellular eukaryotic organisms that generally do not fit in any other kingdom

transposons

small mobile DNA segments

micro-RNA (miRNA)

small single stranded RNA molecules that bind to mRNA and can degrade mRNA or block its translation.

cloning

somewhat slow process by which a desired sequence of DNA is copied numerous times

synaptic cleft

space between two connecting neurons where neurotransmitters are released

substrate

specific reactant acted on by an enzyme

auxin

stem elongation, gravitrophism, phototropism

gibberellins

stem elongation, induce growth in dormant seeds, buds, flowers

FSH

stimulate oogenesis in females and spermatogenesis in males; creates follicle that surrounds the primary oocyte during development

LH

stimulates ovulation, increases estrogen/progesterone release

FSH

stimulates production of eggs or sperm

testosterone

stimulates sperm production; develops male secondary sex characterstics

LH

stimulates the ovulation and production of estrogen and progesterone in females; stimulates production of testosterone and sperm in males

oxytocin

stimulates uterine contraction and milk ejection

CAM plants

store the organic acids made at night in vacuoles and use them for photosynthesis during the day when stomata are closed

stomata

structure through which CO2 enters a plant, and water vapor and oxygen leave plant

ethology

study of animal behavior

demography

study of populations

taxonomy

study of the general principles of scientific classification

nonsense mutation

subsitution of wrong nucleotide into DNA that produces an early stop codon

missense mutation

subsitution of wrong nucleotide into DNA; still produces a protein

antigen

substance that triggers an immune response

stem

supporting structure that connects roots and leaves and carries water and nutrients between them

turgid

swollen and distended or congested

lichen

symbiotic association between a fungus and a photosynthetic organism

types of roots

taproot system and fibrous root system

species

taxonomic group whose members can interbreed

polymerase chain reaction

technique that allows molecular biologists to make many copies of a particular gene

gel electrophoresis

technique used to separate DNA according to size. DNA moves from - to +

phototropism

tendency of plants to grow toward a source of light

circadian rhythms

the 24-hour biological cycles found in humans and many other species

pleiotrophy

the ability of a single gene to have multiple effects

inclusive fitness

the ability of individuals to pass their genes not only through the production of their offspring, but also by providing aid to enable closely related individuals to produce offspring

hybridization

the act of mixing different species or varieties of animals or plants and thus to produce hybrids

metabolic rate

the amount of energy an animal uses in a unit of time

adaptations

the behaviors and physical characteristics that allow organisms to live successfully in their environments

ground tissue

the body of the plants is divided into collenchyma cells, parenchyma cells, and sclerenchyma cells

ecology

the branch of biology concerned with the relations between organisms and their environment

hyphae

the branching, threadlike tubes that make up the bodies of multicellular fungi

organic chemistry

the chemistry of compounds containing carbon (originally defined as the chemistry of substances produced by living organisms but now extended to substances synthesized artificially)

urea

the chief solid component of mammalian urine

cephalization

the concentration of nerve tissue and sensory organs at the anterior end of an organism

polyploidy

the condition in which an organism has extra sets of chromosomes

gametogenesis

the development and maturation of sex cells through meiosis

acrosomal reaction

the discharge of hydrolytic enzymes from the acrosome, when the sperm contacts an egg

transpiration

the emission of water vapor from the leaves of plants

exoskeleton

the exterior protective or supporting structure or shell of many animals (especially invertebrates) including bony or horny parts such as nails or scales or hoofs

endosperm

the food supply for a plant embryo found inside a seed

allopatric speciation

the formation of new species in populations that are geographically isolated from one another

sinoatrial node

the heart's pacemaker, located in the wall of the right atrium

crossing over

the interchange of sections between pairing homologous chromosomes during the prophase of meiosis

cerebral cortex

the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center

balanced polymorphism

the maintainance of two or more phenotypic variants

thermoregulation

the maintenance of body temperature within a range that enables cells to function efficiently

adenosine triphosphate

the molecule that stores energy that can be used by the cell

dispersal

the movement of organisms from one place to another

pangea

the name of the single landmass that broke apart 200 million years ago and gave rise to today's continents

half-life

the period of time in which half of a radioactive substance decays

conservation

the preservation and careful management of the environment and of natural resources

cell differentiation

the process by which a cell becomes specialized for a specific structure or function.

fermentation

the process by which cells break down molecules to release energy without using oxygen

excretion

the process by which wastes are removed from the body

cell differentiation

the process of cell specialization

cleavage

the process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically, the succession of rapid cell divisions without growth during early embryonic development that converts the zygote into a ball of cells

oogenesis

the process of female gamete formation (one ovum from each cell)

spermatogenesis

the process of male gamete formation (four sperm from one cell)

perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

peristalsis

the process of wave-like muscle contractions of the alimentary tract that moves food along

flower

the reproductive structure of an angiosperm

mimicry

the resemblance of an animal species to another species or to natural objects

gel electrophoresis

the separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel

phylogeny

the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms

stomata

the small openings on the undersides of most leaves through which oxygen and carbon dioxide can move

plasmids

the small, circular segments of DNA that are found in bacteria and that stay sparate from the bacterial chromosomes; used in genetic engineering

minimum viable population

the smallest population size at which a species is able to sustain its numbers and survive

niche

the status of an organism within its environment and community (affecting its survival as a species)

behavioral ecology

the study of interaction between animals and their environment

crop rotation

the system of growing a different crop in a field each year to preserve the fertility of the land

hertiability

the traits to be selected for must be able to be passed along to offspring

phosphorylation

the transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by phosphorylation

pollination

the transfer of pollen from male reproductive structures to female reproductive structures in plants

complete metamorphosis

the transformation of a larva into an adult that looks very different, and often functions very differently in its environment, than the larva

law of segregation

the two alleles for a trait separate during the formation of gametes--one to each gamete

bioremediation

the use of living organisms to detoxify and restore polluted and degraded ecosystems

symmetry

the way an animal's body parts match up around a point or central line

amniotes

their embryos are protected by external membranes

Hardy-Weinberg equilibrium

theory of a stable, nonevolving population in which frequency of alleles do not change; only occurs in large, isolated populations with random mating, and no natural selection or mutations

hetertroph theory

theory that describes how life evolved from original heterotrophs

one gene-one polypeptide hypothesis

there is one gene that codes for one polypeptide

differential reproductive success

there must be variation amoung parents in how many offspring they produce as a result of the different traits that the parent have

viroids

tiny plant viruses

platelets

tiny, disk-shaped bodies in the blood, important in blood clot formation

anatomy of plants

tissue systems are divided into ground, vascular, and dermal

vascular tissue

tissue that conducts water and nutrients through the plant body in higher plants

holandric trait

trait that is inherited via the Y chromosome

homologous character

traits similar between organisms that arose from a common ancestor

convergent character

traits similar to two or more organisms that do not share common ancestor; parallel evolution

polygenetic traits

traits that are affected by more then one gene (eye color or skin color)

multiple alleles

traits that correspond to more than two alleles

conjugation

transfer of DNA between two bacterial cell connected by sex pili

phloem

transports sugar in plants

xylem

transports water and minerals in plants

operant conditioning

trial-and-error learning

codon

triplet of nucleotides that codes for a particular amino acid

Mullerian mimicry

two aposemetrically colored species have similar coloration pattern

dehydration

two components brought together, producing H2O

diploid (2n)

two copies of each chromosome

balanced polymorphism

two phenotypic variants become so different that the two groups stop interbreeding

divergent evolution

two related spevies evolve in a way that makes them less similar

convergent evolution

two unrelated species evolve in a way that makes them more similar

binary fission

type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical daughter cells

endospore

type of spore formed when a bacterium produces a thick internal wall that encloses its DNA and a portion of its cytoplasm

roots

underground organs that absorb water and minerals

diatoms

unicellular algae that have a unique glass-like wall made of hydrated silica embedded in an organic matrix

altruism

unselfish regard for the welfare of others

transformation

uptake of foreign DNA from the surrounding environment

carbohydrates

used by cells for energy and stucture; monosaccharides (glucose), disaccharides (sucrose, maltose, lactose), storage polysaccharides (starch [plants], glycogen [animals]), structural polysaccharides (chitin [fungi], cellulose [arthropods])

specialized transduction

virus leaving lysogenic cycle brings host DNA with it into phage

prion

virus that converts host brain proteins into misshapen proteins

phage

virus that infects bacteria

aposematic coloration

warning coloration adopted by animals that posses a chemical defense mechanism

hydrogen bond

weak chemical bond formed by the attraction of positively charged hydrogen atoms to other negatively charged atoms

Hamilton's rule

when C < r x B C = cost to the altruistic party r = genetic relatedness B = fitness benefit to recipient of altuism

hypertonic

when comparing two solutions, the solution with the greater concentration of solutes

vascular tissue

xylem and phloem

human life cycle

zygote (2n) -> multicellular orgainsm (2n) -> gametes (n) -> zygote (2n)

fungi life cycle

zygote (2n) -> multicellular orgainsm (n) -> gametes (n) -> zygote (2n)

plants life cycle

zygote (2n) -> sporophyte (2n) -> spores (n) -> gametophyte (n) -> gametes (n) -> zygote (2n)