AP Biology Exam

negative feedback pathways

-involves endocrine cells, hormones, and tissue cells -long distance signaling -WITH HIGH BS: when glycogen is released, blood sugar is raised. This leads to secretion of insulin which pass through pancreas. When low, insulin attempts to move glucose from blood into cells for vitality

functions of poly A tail

-facilitate the export of the mature mRNA from the nucleus -they help protect the mRNA from degradation by hydrolytic enzymes -help attach the 5' end of the mRNA once it reaches the cytoplasm

saturated fat

-fat made from saturated fatty acids -mostly animal fats such as lard and butter -solid at room temperature -straight

unsaturated fat

-fat made from unsaturated fatty acids -usually plants and fish -liquid at room temperature and often referred to as oils -kinks from cis double bonds prevent the molecules from packing together closely (bent)

free-floating ribosomes vs bound ribosomes

-free floating ribosomes make up proteins that function within the cytosol -bound ones make proteins that are destined for insertion into membrnes, for packaging within certain organelles such as lysosomes, or for export from the cell (secretion)

protein structure depends on what?

-interactions responsible for secondary and tertiary structure -physical and chemical conditions - pH, salt conc., temperature, etc.

Neurotrasmitters

-involves post synaptic cells, presynaptic cells, CAT molecules -paracrine signaling -nuerotransmitters depolarize the plasma membrane when action potential arrives. Then CAT molcules diffuse into axon and cause vesicles to fuse, NT are released into S cleft. NT binds to membrane protein, which opens channel, allowing NAT molecules to diffuse into post _ KT out - exilatory post synaptic protential

plant respones - hormones, immune, tropisms

-long distance signaling -involve plant cells and PAMP -protection of plant by epidermis. After physical barrier is invaded by pathogens, PAMP triggered immunity becomes active. PAMP recognized in plants triggers chain of signaling events leading to production of anti-microbial chemicals

Positive feedback pathways

-long distance signaling -involves receptor cells and embryonic cells -stimulus-variable-receptor-senses change-control center compares against ref val-effectors make adjustments in same direction-back to variable

aerobic respiration

A catabolic pathway for organic molecules, using oxygen (O2) as the final electron acceptor in an electron transport chain and ultimately producing ATP. This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms.

fermentation

A catabolic process that makes a limited amount of ATP from glucose without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid.

diploid cell

A cell containing two sets of chromosomes (2n), one set inherited from each parent

transformation

A change in genotype and phenotype due to the assimilation of external DNA by a cell. When the external DNA is from a member of a different species, transformation results in horizontal gene transfer

Mutations

A change in the nucleotide sequence of an organism's DNA, ultimately creating genetic diversity. Mutations also can occur in the DNA or RNA of a virus.

aquaporins

A channel protein in the plasma membrane of a plant, animal, or microorganism cell that specifically facilitates osmosis, the diffusion of free water across the membrane.

catalysts

A chemical agent that selectively increases the rate of a reaction (by lowering the activation energy) without being consumed by the reaction.

catalyst

A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction.

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

citric acid cycle

A chemical cycle involving eight steps taht completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidyzing acetyl CoA (derived from pyruvate) to carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes

Mutagen

A chemical or physical agent that interacts with DNA and causes a mutation.

dehydration synthesis

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule. (an OH from one polymer and an H from another)

redox reactions

A chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another; short for reduction-oxidation reaction

redox reaction

A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction.

hydrolysis

A chemical reaction that breaks bonds between two molecules by the addition of water; functions in disassembly of polymers to monomers.

Aneuploidy

A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number.

Polyploidy

A chromosomal alteration in which the organism possesses more than two complete chromosome sets. (3n 4n) - common in plants

recombinant chromosome

A chromosome created when crossing over combines the DNA from two parents into a single chromosome.

ribosomes

A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a large and a small subunit. In eukaryotic cells, each subunit is assembled in the nucleolus. -the site of translation

ATP synthase

A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP (matrix to inner mem space). ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes.

intermediate filaments

A component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments. more permanent fixture of the cell, specialized for bearing tension. ex: keratins in hair and nails

checkpoint

A control point in the cell cycle where stop and go-ahead signals can regulate the cycle.

glycosidic linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

monohybrid cross

A cross between two organisms that are heterozygous for the character being followed (or the self-pollination of a heterozygous plant).

barr body

A dense object lying along the inside of the nuclear envelope in female mammalian cells, representing an inactivated X chromosome.

pedigree

A diagram of a family tree showing the occurrence of heritable characters in parents and offspring over multiple generations.

gene

A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses).

complementary DNA

A double-stranded DNA molecule made in vitro using mRNA as a template and the enzymes reverse transcriptase and DNA polymerase.

basal body

A eukaryotic cell structure consisting of a "9 + 0" arrangement of microtubule triplets. The basal body may organize the microtubule assembly of a cilium or flagellum and is structurally very similar to a centriole.

saturated fatty acid

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that can attach to the carbon skeleton.

unsaturated fatty acid

A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

thylakoid

A flattened, membranous sac inside a chloroplast. Thylakoids often exist in stacks called grana that are interconnected; their membranes contain molecular "machinery" used to convert light energy to chemical energy.

x-linked gene

A gene located on the X chromosome; such genes show a distinctive pattern of inheritance.

regulatory gene

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

tumor suppressor genes

A gene whose protein product inhibits cell division, thereby preventing the uncontrolled cell growth that contributes to cancer.

collagen

A glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone; the most abundant protein in the animal kingdom and in the ECM.

gametes

A haploid reproductive cell, such as an egg or sperm, that is formed by meiosis or is the descendant of cells formed by meiosis. Gametes unite during sexual reproduction to produce a diploid zygote.

quantitative character

A heritable feature that varies continuously over a range rather than in an either-or fashion.

microtubules

A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella. -they grow in length by adding tubilin dimers (proteins)

Huntington's disease

A human genetic disease caused by a dominant allele; characterized by uncontrollable body movements and degeneration of the nervous system; usually fatal 10 to 20 years after the onset of symptoms.

tay-sachs disease

A human genetic disease caused by a recessive allele with a dominant allele (codominance) 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.

Hemophilia

A human genetic disease caused by a sex-linked recessive allele; characterized by excessive bleeding following injury.

duchenne muscular dystrophy

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

down syndrome

A human genetic disease usually caused by the presence of an extra chromosome 21; characterized by developmental delays and heart and other defects that are generally treatable or non-life-threatening.

cystic fibrosis

A human genetic disorder caused by a recessive allele for a chloride channel protein; characterized by an excessive secretion of mucus and consequent vulnerability to infection; fatal if untreated.

G0 phase

A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly. -most mature nerve and muscle cells never divide so they stay in G0 while other cells such as liver cells can be "called back" to the cell cycle by external cue (such as growth factors released during injury)

endergonic reaction

A nonspontaneous chemical reaction, in which free energy is absorbed from the surroundings.

silent mutation

A nucleotide-pair substitution that has no observable effect on the phenotype; for example, within a gene, a mutation that results in a codon that codes for the same amino acid.

homologous chromosomes

A pair of chromosomes of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organism's father, the other from the mother. Also called homologs, or a homologous pair.

plasmolysis

A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water to a hypertonic environment. causes plant to wilt and can lead to plant death

polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

nucleic acid

A polymer consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular structures and activities. The two types of nucleic acids are DNA and RNA.

catalysis

A process by which a chemical agent called a catalyst selectively increases the rate of a reaction without being consumed by the reaction.

autophagy

A process in which lysosomes decompose damaged organelles to reuse their organic monomers

cell wall

A protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists.

peripheral protein

A protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer.

activator

A protein that binds to DNA and stimulates gene transcription. In prokaryotes, activators bind in or near the promoter; in eukaryotes, activators generally bind to control elements in enhancers.

single strand binding protein

A protein that binds to the unpaired DNA strands during DNA replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary strands of DNA.

topoisomerase

A protein that breaks, swivels, and rejoins DNA strands. During DNA replication, topoisomerase helps to relieve strain in the double helix ahead of the replication fork.

repressor

A protein that inhibits gene transcription. In prokaryotes, repressors bind to the DNA in or near the promoter. In eukaryotes, repressors may bind to control elements within enhancers, to activators, or to other proteins in a way that blocks activators from binding to DNA. (they are specific)

motor proteins

A protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell.

glycoprotein

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

receptor tyrosine kinases

A receptor protein spanning the plasma membrane, the cytoplasmic (intracellular) part of which can catalyze the transfer of a phosphate group from ATP to a tyrosine on another protein. receptor for growth molecuels

sickle-cell disease

A recessively inherited human blood disorder in which a single nucleotide change in the beta-globin gene causes hemoglobin to aggregate, changing red blood cell shape and causing multiple symptoms in afflicted individuals.

concentration gradient

A region along which the density of a chemical substance increases or decreases.

transcription unit

A region of DNA that is transcribed into an RNA molecule.

transcription factor

A regulatory protein that binds to DNA and affects transcription of specific genes.

addition rule

A rule of probability stating that the probability of any one of two or more mutually exclusive events occurring can be determined by adding their individual probabilities.

multiplication rule

A rule of probability stating that the probability of two or more independent events occurring together can be determined by multiplying their individual probabilities.

cyclic AMP

A second messenger derived from ATP and triggers specific cellular changes in metabolic regulation. goes through the cell membrane and has receptor molecules in cytoplasm

control element

A segment of noncoding DNA that helps regulate transcription of a gene by serving as a binding site for a transcription factor. Multiple control elements are present in a eukaryotic gene's enhancer.

signal peptide

A sequence of about 20 amino acids at or near the leading (amino) end of a polypeptide that targets it to the endoplasmic reticulum or other organelles in a eukaryotic cell.

electron transport chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP. (takes place in inner membrane of mitochondria)

exons

A sequence within a primary transcript that remains in the RNA after RNA processing; also refers to the region of DNA from which this sequence was transcribed. (they are eventually expressed)

metabolic pathway

A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds.

glycolysis

A series of reactions that ultimately splits glucose into pyruvate. Occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration

signal transduction pathway

A series of steps linking a mechanical or chemical stimulus to a specific cellular response.

okazaki fragments

A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication. Many such segments are joined together to make up the lagging strand of newly synthesized DNA. (due to antiparallel structure)

G protein-coupled receptor

A signal receptor protein in the plasma membrane that responds to the binding of a signaling molecule by activating a G protein.

histones

A small protein with a high proportion of positively charged amino acids that binds to the negatively charged DNA and plays a key role in chromatin structure.

functional group

A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions.

promoter

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

locus

A specific place along the length of a chromosome where a given gene is located.

inducer

A specific small molecule that binds to a bacterial repressor protein and changes the repressor's shape so that it cannot bind to an operator, thus switching an operon on.

exergonic reaction

A spontaneous chemical reaction in which there is a net release of free energy. (G is lost therefore G is negative) -occur spontaneously

cholesterol

A steroid that at high temperatures, makes the membrane less fluid by restraining phospholipid movement and also lowers the temperature required for the mem to solidify -helps membranes resist changes in fluidity when temp changes

cholesterol

A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids. -synthesized in the liver and obtained from the diet

starch

A storage polysaccharide in plants consisting entirely of glucose monomers -can be withdrawn for energy in plants by hydrolysis

disulfide bridges

A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer.

chitin

A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all arthropods.

centrosome

A structure in animal cells containing 2 centrioles from which the spindle fibers develop. functions as microtubule-organizing center -in plant cells the centrosome anchors the cell

kinetochore

A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle.

centrosome

A structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division. A centrosome has two centrioles. *NOT ESSENTIAL TO CELL DIVISION, IF DESTROYED, A SPINDLE STILL FORMS

noncompetitive inhibitor

A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.

competitive inhibitors

A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics.

polymerase chain reaction

A technique for amplifying DNA in vitro by incubating it with specific primers, a heat-resistant DNA polymerase, and nucleotides.

RT-PCR

A technique for determining expression of a particular gene. It uses reverse transcriptase and DNA polymerase to synthesize cDNA from all the mRNA in a sample and then subjects the cDNA to PCR amplification using primers specific for the gene of interest.

gel electrophoresis

A technique for separating nucleic acids or proteins on the basis of their size and electrical charge, both of which affect their rate of movement through an electric field in a gel made of agarose or another polymer.

in situ hybridization

A technique using nucleic acid hybridization with a labeled probe to detect the location of a specific mRNA in an intact organism.

enzyme substrate complex

A temporary complex formed when an enzyme binds to its substrate molecule(s).

microfibrils

A threadlike component of the cell wall, composed of cellulose molecules

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. (written in the 5'-3' direction)

ion channels

A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient.

ligand-gated ion channel

A transmembrane protein containing a pore that opens or closes as it changes shape in response to a signaling molecule (ligand), allowing or blocking the flow of specific ions; also called an ionotropic receptor.

transport proteins

A transmembrane protein that helps a certain substance or class of closely related substances (hydrophylic substances) to cross the membrane. (very selective to its certain substance!!!!)

integral proteins

A transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane (or lining the channel in the case of a channel protein). (the hydrophobic regions consist of one or more stretches of nonpolar amino acids - coiled by alpha helixes)

mRNA

A type of RNA, synthesized using a DNA template, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

phagocytosis

A type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It is carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophils, and dendritic cells).

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

alternative RNA splicing

A type of eukaryotic gene regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns.

epistasis

A type of gene interaction in which the phenotypic expression of one gene alters that of another independently inherited gene

gap junctions

A type of intercellular junction in animal cells that allows the passage of material or current between cells.

steroids

A type of lipid characterized by a carbon skeleton consisting of four rings with various functional groups attached.

endocrine signaling

A type of long-distance signaling in animals that utilizes hormones.

myosin

A type of motor protein that associates into filaments that interact with actin filaments to cause cell contraction.

nucleotide-pair substitution

A type of point mutation in which one nucleotide in a DNA strand and its partner in the complementary strand are replaced by another pair of nucleotides.

operon

A unit of genetic function found in bacteria and phages, consisting of a promoter, an operator, and a coordinately regulated cluster of genes whose products function in a common pathway.

bacteriophage

A virus that infects bacteria; also called a phage.

start codon

AUG (methionine)

Acetyl CoA

Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme.

purines

Adenine and Guanine -nitrogenous bases with two organic rings

bases for DNA

Adenine, Thymine, Cytosine, Guanine

When does the chromatin condense into chromosomes?

After DNA replication, prophase?

RNA splicing

After synthesis of a eukaryotic primary RNA transcript, the removal of portions of the transcript (introns) that will not be included in the mRNA and the joining together of the remaining portions (exons).

ribozymes

An RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing.

transfer rna

An RNA molecule that functions as an translator between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA

signal recognition particle (SRP)

An RNA-protein complex that binds with part of a polypeptide chain and marks the molecule for incorporation into the endoplasmic reticulum (eukaryotes) or the plasma membrane (prokaryotes).

duplication

An aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is duplicated.

translocation

An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome.

inversion

An aberration in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated.

proton pump

An active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process. (helpful for ATP synthesis during cellular resp)

electrogenic pump

An active transport protein that generates voltage across a membrane while pumping ions.

polygenic inheritance

An additive effect of two or more genes on a single phenotypic character. Characters that vary along a continuum, following a normal distribution, are often controlled by multiple genes, each contributing to the phenotype in an additive fashion.

atp

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

ectotherm

An animal whose body does not produce much internal heat

mitotic spindle

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

restriction enzymes

An endonuclease (type of enzyme) that recognizes and cuts DNA molecules foreign to a bacterium (such as phage genomes). The enzyme cuts at specific nucleotide sequences (restriction sites).

Chemiosmosis

An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP.

nuclease

An enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides.

primase

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

aminoacyl-tRNA synthetase

An enzyme that joins each amino acid to the appropriate tRNA.

rna polymerase

An enzyme that links ribonucleotides into a growing RNA chain during transcription, based on complementary binding to nucleotides on a DNA template strand.

reductase

An enzyme that promotes the chemical reduction of a specified substance.

protein phosphatases

An enzyme that removes phosphate groups from proteins, often functioning to reverse the effect of a protein kinase.

protein kinase

An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein.

helicase

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

nondisjunction

An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other.

endoplasmic reticulum

An extensive membranous network in a eukaryotic cell, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions. -consists of network of membranous tubules and sacs called cisternae -internal part is called the ER LUMEN or cisternal space

glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch. -mainly located in liver and muscle cells

fibronectin

An extracellular glycoprotein secreted by animal cells that helps them attach to the extracellular matrix.

metaphase plate

An imaginary structure located at a plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located.

two types of cells

Prokaryotic and Eukaryotic

Ribosomal RNA

RNA molecules that, together with proteins, make up ribosomes; the most abundant type of RNA

nucleosome

The basic, bead-like unit of DNA packing in eukaryotes, consisting of a segment of DNA wound around a protein core composed of two copies of each of four types of histone.

allosteric regulation

The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site.

reception

The binding of a signaling molecule to a receptor protein, activating the receptor by causing it to change shape.

energy

The capacity to cause change, especially to do work (to move matter against an opposing force).

cellular respiration

The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP.

mismatch repair

The cellular process that uses specific enzymes to remove and replace incorrectly paired nucleotides.

Exocytosis

The cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane. ex) pancreas cells secrete insulin or nerve cells release nuerotransmitters

endomembrane system

The collection of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles; includes the plasma membrane, the nuclear envelope, the smooth and rough endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, and vacuoles.

mitochondrial matrix

The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle.

reduction

The complete or partial addition of electrons to a substance involved in a redox reaction

oxidation

The complete or partial loss of electrons from a substance involved in a redox reaction

transcription initiation complex

The completed assembly of transcription factors and RNA polymerase bound to a promoter.

chromatin

The complex of DNA and proteins that makes up eukaryotic chromosomes. When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope

cotransport

The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient. ex) plant cells use the gradient of hydrogen generated by proton pumps to drive the active transport of amino acids, sugars, and other nutrients into the cell (sucrose)

fluid mosaic model

The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of individually inserted protein molecules drifting laterally in a fluid bilayer of phospholipids.

stroma

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

membrane potential

The difference in electrical charge (voltage) across a cell's plasma membrane due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances. -inside of a cell is negative compared to the outside

electrochemical gradient

The diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential.

oxidizing agent

The electron acceptor in a redox reaction.

reducing agent

The electron donor in a redox reaction.

kinetic energy

The energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter.

NADP+

The oxidized form of nicotinamide adenine dinucleotide phosphate, an electron carrier that can accept electrons, becoming NADPH. NADPH temporarily stores energized electrons produced during the light reactions.

facilitated diffusion

The passage of molecules or ions down their electrochemical gradient across a biological membrane with the assistance of specific transmembrane transport proteins, requiring no energy expenditure.

mitotic phase

The phase of the cell cycle that includes mitosis and cytokinesis.

density-dependent inhibition

The phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another. (crowded cells stop dividing, they will resume if they need to fill open space) -the binding of a cell-surface protein to its counterpart on an adjoining cell sends a signal to both cells that inhibits cell division, preventing them from moving forward in the cell cycle, even in the presence of growth factors.

wild type

The phenotype most commonly observed in natural populations; also refers to the individual with that phenotype.

free energy

The portion of a biological system's energy that can perform work when temperature and pressure are uniform throughout the system.

proton-motive force

The potential energy stored in the form of an electrochemical gradient, generated by the pumping of hydrogen ions across biological membranes during chemiosmosis.

dna methylation

The presence of methyl groups on the DNA bases (usually cytosine) of plants, animals, and fungi. (The term also refers to the process of adding methyl groups to DNA bases.)(represses gene transcription and changes the dnas activity)

gene expression

The process by which information encoded in DNA directs the synthesis of proteins or, in some cases, RNAs that are not translated into proteins and instead function as RNAs.

nucleic acid hybridization

The process of base pairing between a gene and a complementary sequence on another nucleic acid molecule.

cleavage

The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane

photophosphorylation

The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis.

oxidative phosphorylation

The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.

substrate

The reactant on which an enzyme works.

NADPH

The reduced form of nicotinamide adenine dinucleotide phosphate; temporarily stores energized electrons produced during the light reactions. NADPH acts as "reducing power" that can be passed along to an electron acceptor, reducing it.

NADH

The reduced form of nicotinamide adenine dinucleotide that temporarily stores electrons during cellular respiration. NADH acts as an electron donor to the electron transport chain.

anchorage dependence

The requirement that a cell must be attached to a substratum in order to initiate cell division.

meiosis II

The second division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell.

G2 phase

The second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

calvin cycle

The second of two major stages in photosynthesis (following the light reactions), involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate. -takes place stroma

cytosol

The semifluid portion of the cytoplasm.

complete dominance

The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable.

metastasis

The spread of cancer cells to locations distant from their original site.

thermodynamics

The study of energy transformations that occur in a collection of matter.

translation

The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of language from nucleotides to amino acids.

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated. -duplication of chromosmes

endosymbiont theory

The theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism.

metaphase

The third stage of mitosis, in which the spindle is complete and the chromosomes, attached to microtubules at their kinetochores, are all aligned at the metaphase plate. *the M checkpoint takes place during this step, ensuring all chromosomes are attached to spindle fibers before anaphase

metabolism

The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.

P generation

The true-breeding (homozygous) parent individuals from which F1 hybrid offspring are derived in studies of inheritance; P stands for "parental."

Why is fat and petroleum hydrophobic?

They are hydrophobic because they contain hydrocarbon tails that are made up of a majority nonpolar carbon-to-hydrogen linkages. (They also are known to release a large amount of energy but unrelated)

sister chromatids

Two copies of a duplicated chromosome attached to each other by proteis at the centromere and sometimes, along the arms. While joined, two sister chromatids make up one chromosome. Chromatids are eventually separated during mitosis or meiosis II

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.

stop codons

UAA, UAG, UGA

ester linkage

a bond between a hydroxyl group and a carboxyl group

haploid cell

a cell containing only one set of chromosomes (n)

chromosome

a cellular structure consisting of one DNA molecule and associated protein molecules.

chromosome

a cellular structure consisting of one DNA molecule and associated protein molecules. A eukaryotic cell typically has mulitple, linear chromosomes, which are located in the nucleus. A prokaryotic cell often has a single, circular chromosome, which is found in the nucleoid, a region that is not enclosed by a membrane

point mutation

a change in a single nucleotide pair of a gene

condensation reaction

a chemical reaction in which two or more molecules combine to produce water or another simple molecule -how DNA polymerase catalyzes the addition of each monomer to the growing end of a DNA strand

sex chromosomes

a chromosome responsible for determining the sex of an individual

ribosomes

a complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a large subunit and a small subunit

Punnett Square

a diagram used in the study of inheritance to show the predicted genotypic results of random fertilization in genetic crosses between individuals of known genotype

gene

a discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses)

sex-linked gene

a gene located on either sex chromosome

triplet code

a genetic information system in which sets of three-nucleotide-long words specify the amino acids for polypeptide chains

clone

a group of genetically identical individuals or cells

glycolipids

a lipid with one or more covalently attached carbohydrates

polymer

a long molecule consisting of many similar or identical building blocks linked by covalent bonds. carbohydrates, proteins, and nucleic acids are examples of this.

lysosome

a membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm off animal cells and some protists -three dimensional shape of lysosomal proteins that protect vulnerable bonds from enzymatic attack

vesicle

a membranous sac in the cytoplasm of a eukaryotic cell

contractile vacuoles

a membranous sac that helps move excess water out of certain freshwater protists

anabolic pathways

a metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules (ex synthesis of amino acids) "uphill"

beta oxidation

a metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA

synaptic signaling

a nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell

DNA

a nucleic acid molecule, usually a double-stranded helix, in which each polynucleotide stand consists of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases A,T,C,G; capable of being replicated and determing the inherited structure of a cells proteins

missense mutation

a nucleotide-pair substitution that results in a codon that codes for a different amino acid (could possibly have little effect on the protein)

DNA

a polymer of nucleotides, each having three components: a nitrogenous base, a pentose sugar called deoxyribose, and a phosphate group

transduction

a process in which phages carry bacterial DNA from one bacterial cell to another. When these two cells are members of different species, transduction results in horizontal gene transfer

mitosis

a process of nuclear division in eukary cells conventionally divided into five stages: PMAT. Mitosis conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei.

spontaneous process

a process that occurs without an overall input of energy; a process that is energetically favorable

glycoproteins

a protein with one or more covalently attached carbs

enhancer

a segment of eukaryotic DNA containing multiple control elements, usually located far from the gene whose transcription it regulates

poly-A tail

a sequence of 50-250 adenine nucleotides added onto the 3' end of a pre-mRNA molecule

primer

a short polynucleotide with a free 3' end, bound by complementary base pairing to the template strand and elongated with DNA nucleotides during DNA replication (generally 5-10 nucleotides long)

corepressor

a small molecule that binds to a bacterial repressor protein and changes the protein's shape, allowing it to bind to the operator and switch an operon off

plasmid

a small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome

nucleolus

a specialized structure in the nucleus, consisting of chromosomal regions containing ribosomal RNA (rRNA) genes along with ribosomal proteins imported from the cytoplasm; site of rRNA synthesis and ribosomal subunit assembly

cellulose

a structural polysaccharide of plant cell walls, consisting of glucose monomers joined by beta glycosidic linkages

gated channels

a transmembrane protein channel that opens or closes in response to a particular stimulus (includes many ion channels)

juxtacrine signaling

a type of cell signaling between two cells that directly contact one another

tight junction

a type of intercellular junction between animal cells that prevents the leakage of material through the space between cells

RNA

a type of nucleic acid consisting of a polynucleotide made up of nucleotide monomers with a ribose sugar and the nitrogenous bases A,C,G,U; usually singe-stranded; functiions in protein synthesis, gene regulation, and as the genome of some viruses

cilia

a type of protist that moves by means of cilia

synaptonemal complex

a zipper-like structure composed of proteins, which connects two homologous chromosomes tightly along their lengths

major function of fats

energy storage -store twice as much energy as a gram of a polysacc like starch -this is good for animals because we need a compact reservoir of fuel - fat

Uses of polysaccharides

energy storage (starch and glycogen) structural support (cellulose and chitin) -these are determined by its sugar monomers and by the positions of its glycosidic linkages

potential energy

energy that matter possesses because of its location or structure

hydrolytic enzymes

enzymes that speed up/aid in the breakdown of chemical bonds through the addition of water (hydrolysis) -made by rough er and then transferred to GA for further processing

sodium-potassium pump

example of active transport -an animal cell has a much higher conc. of potassium ions and a much lower conc. of sodium ions, the pump helps maintain these steep gradients by pumping sodium out and potassium into the cell

Hydrolysis of ATP

exergonic

Where does the free energy required to phosphorylate ADP come from?

exergonic breakdown reactions (catabolism)

cell signaling

external signals are converted into responses within the cell

centromere

in a duplicated chromosome, the region on each sister chromatid where it is most closely attached to its sister chromatid by proteins that bind to the centromeric DNA. Other proteins condense the chromatin in that region (which is why it appears narrow)

nuclear envelope

in a eukaryotic cell, the double membrane that surrounds the nucleus, perforated with pores that regulate traffic with the cytoplasm. The outer membrane is continuous with the ER

central vacuole

in a mature plant cell, a large membranous sac with diverse roles in growth, storage, and sequestration of toxic substances

energy coupling

in cellular metabolism, the use of energy released from an exergonic reaction to drive an energonic reaction (atp is responsible for mediating most energy coupling in cells)

dynein

in cilia and flagella, a large motor protein extending from one microtubule doublet to the adjacent doublet. ATP hydrolysis drives changes in dynein shape that lead to bending of cilia and flagella

hormones

in multicellular organisms, one of many types of secreted chem that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the body, changing the target cells functioning. important in long distance signaling

hormone

in multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the body, changing the target cells' functioning. Hormones are thus important inn IonG-distance signaling

start point

in transcription, the nucleotide position on the promoter where RNA polymerase begins synthesis of RNA

Three mechanisms contribute to genetic variation

independent assortment of chromosomes, crossing over, random fertilization

monomer of nucleic acids

nucleotides

How to find out the number of electrons?

number of electrons is equal to protons in a neutral atom

P site

one of a ribosome's three binding sites for tRNA during translation. It holds the tRNA carrying the growing polypeptide chain.

geometric isomers

one of two or more compounds that have the same molecular formula and covalent bonds between atoms but differ in the spatial arrangements of their atoms owing to the inflexibility of double bonds.

trait

one of two or more detectable variants in a genetic character

what type of cells can undergo meiosis

only diploid cells

hydrocarbons

organic molecules consisting of only carbon and hydrogen

which organic molecules are excellent fuels?

organic molecules with an abundance of hydrogen because their bonds are a source of electrons that could release energy as they fall down the energy gradient during their transfer to oxygen

origin of replication

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

codominance

situation in which the phenotypes produced by both alleles are completely expressed

transport vesicle

small membranous sac in a eukaryotic cells cytoplasm carrying molecules produced by the cell

microRNA

small single stranded RNA molecule, generated from a hairpin structure on a precursor RNA transcribed from a particular gene. The miRNA associates with one or more proteins in a complex that can degrade or prevent translation of an mRNA with a complementary sequence

roles proteins play

some speed up chemical reactions, other play a role in defense, storage, transport, cellular communication, movement, or structural support

enzymes

specialized macromolecules (usually proteins) that speed up chemical reactions

difference between starch and cellulose

starch: glucose monomers are in alpha configuration -OH group below #1 Carbon cellulose: glucose monomers are in beta configuration -OH group above #1 Carbon Glycosidic Linkages: starch-helical; cellulose straight

three types of isomers

structural, geometric, enantiomers

most prevalent disaccharide

sucrose (table sugar) made from the monomers glucose and fructose

What does the estimate of ATP yield from cellular respiration depend on?

supply of oxygen to the cell

turgid

swollen or distended, as in plant cells (a walled cell becomes turgid if it has a lower WP than its surroundings, resulting in entry of water)

RNA interference

technique to silence the expression of selected genes in nonmammalian organisms; uses synthetic double-stranded RNA molecules matching the sequence of a particular gene to trigger the breakdown of the gene's messenger RNA

tonicity

the ability of a surrounding solution to cause a cell to gain or lose water

carboxyl group

the acid group attached to one end of the fatty acid chain

the level of mitochondria correlates to what?

the cells level of metabolic activity

chromatin

the complex of dna and proteins that makes up eukaryotic chromosomes. When the cell is not dividing chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope

An enzyme is saturated when

the concentration of substrate will be high enough that all enzyme molecules will have their active sites engaged.

particulate inheritance

the concept of heredity based on the transmission of genes (alleles) according to Mendelian principles

histone methylation

the condensing of chromatin structure (heterochromatin), prevents transcription

Cytoplasm

the contents of the cell enclosed b the plasma membrane; in eukaryotes, the portion exclusive of the nucleus

test cross

the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype

passive transport

the diffusion of a substance across a biological membrane with no expenditure of energy

osmosis

the diffusion of free water molecules across a selectively permeable membrane

zygote

the diploid cell produced by the union of haploid gametes during fertilization; a fertilized egg

life cycle

the generation-to-generation sequence of stages in the reproductive history of an organism

plasma membrane

the membrane at the boundary of every cell that acts as a selective barrier, regulating the cells chemical composition

leading strand

the new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5' to 3' direction

atomic mass

the number of protons and neutrons in an atom

atomic number

the number of protons in the nucleus of an atom

quaternary structure of a protein

the overall protein structure that results from the aggregation of these polypeptide subunits association of two or more polypeptides (some proteins only)

synapsis

the pairing and physical connection of duplicated homologous chromosomes during prophase I of meiosis

interphase

the period in the cell cycle when the cell is not dividing. During interphase, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase. Interphase often accounts for about 90% of the cell cycle

water potential

the physical property that predicts the direction in which water will flow

nucleoside

the portion of a nucleotide without the phosphate group

rough er

the portion of the er with ribosomes attached -produces proteins that are secreted by many cells -membrane factory

DNA replication

the process by which a DNA molecule is copied; also called DNA synthesis

transformation

the process by which a cell in culture acquires the ability to divide indefinitely, similar to the division of cancer cells

dna cloning

the production of multiple copies of a specific DNA segment

diffusion

the random thermal motion of particles of liquids, gases, or solids. In the presence of a concentration or electrochemical gradient, diffusion results in the net movement of a sub. from a region where it is more conc. to a region where it is less conc.

cell division

the reproduction of cells

genetics

the scientific study of heredity and hereditary variation

prometaphase

the second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes

incomplete dominance

the situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele -BLENDING OF PHENOTYPES

active site

the specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs

histone acetylation

The attachment of acetyl groups to certain amino acids of histone proteins. -appears to promote transcription by opening up the chromatin structure

How does water moderate air temperature?

by absorbing heat from air that is warmer and releasing the stored heat to air that is cooler

primary structure of a protein

sequence of amino acids -dictates secondary and tertiary structure

cell mediated immune response (adaptive immunity)

-cell to cell signaling -involves cytokines, helper t cells, antigen presenting cells, cytotoxic t cells, and protein CD4 -helper t cell binds to antigen presenting cell with CD4. Cytokines are then secreted by immune cells. Cytokines activate helper t cells which stimulates cell proliferation. Clone cells produce more cytokines (CYTOTOXIC T CELLS) which when activated kills with toxic proteins

morphogens, embryonic development

-cell to cell signaling -involves nurse cells, egg cells, bicoid proteins, and sperm -nurse cell sends bicoid mRNA to the egg cell (throughout). Egg cell is fertilized which activated translation of bicoid mRNA to form bicoid proteins, which forms a conc gradient. Cell divides

how to calculate recombinant frequency and map units

(# of recombinants (unlike parents) / total # of offspring) * 100

deletion

(1) A deficiency in a chromosome resulting from the loss of a fragment through breakage.

plant cells have

- cell wall / plasma membrane -chloroplast AND mitochondria -cytoplasm/cytosol/cytoskeleton -all organelles EXCEPT lysosomes HAVE RIBOSOMES -central vacuole -centrosomes helps anchor the cell

eukaryotic

- consist of organisms of the domain eukarya -nucleus (location of DNA) (bounded by a double membrane) -membrane bound organelles -large (10-100 micrometers)

prokaryotic cells

- consist of the domains bacteria and archaea -nucloid (conc. region of DNA) -lack membrane bound organelles

fluidity of membranes

-A membrane is held together primarily by hydrophobic interactions which are much weaker than covalent bonds -most of the lipids and some proteins can shift about sideways -membrane solidifies as it cools (similar to bacon fat), more kinks in the tails (double bonds) means the tails cannot pack together as closely and the mem is more fluid

nucleus

-An atom's central core, containing protons and neutrons. - the organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made up of chromatin - a cluster of neurons - 5 micrometers in diameter

Permeability of Lipid Bilayer

-Hydrophobic (nonpolar) molecules, such as hydrocarbons, can dissolve in the lipid bilayer and pass through the membrane rapidly -Hydrophilic molecules including ions and polar molecules do not cross the membrane easily, such as glucose and even water -depends on both discriminating barrier of the lipid bilayer and the specific transport proteins built into the membrane

surface tension

-a measure of how difficult it is to stretch or break the surface of a liquid -at the air-water interface is an ordered arrangement of water molecules that are h-bonded to one another and to the water below, but not the air above and this asymmetry gives water an unusually high surface tension

growth factor

-a protein released by certain cells that stimulates other cells to divide -different cell types respond specifically to different growth factors or combinations of growth factors

humoral immune response (adaptive immunity)

-cell to cell signaling -involves cytokines, helper t cells, antigen presenting cells, cytotoxic t cells, and CD4 =helper t cell binds to antigen presenting cell with CD4. Cytokines are produced which activate t cells. Cytokines activate B cells. Plasma cells from B membrane secrete antibodies + how to make antibodies

steps of life cycle

-diploid germ cells go through meiosis -haploid gametes are produced -gametes do not go under anymore cell division prior to mitosis -after fertilization the diploid zygote divides by mitosis, producing a multicellular organism.

animal cells have

-plasma membrane / extracellular matrix -cytoplasm/cytosol/cytoskeleton -all organelles -mitochondria (site of cellular respiration - ATP) -small food vacuoles -centrosomes include centrioles - used to make spindle fibers for cell division

adhesion

-the clinging of one substance to another -adhesion of water to cell walls by h-bonds helps counter the downward pull of gravity

monosaccharides

-the simplest carbohydrates (simple sugar) that are the monomers from which more complex carbs are built -fructose, glucose, galactose, ribose

polar

-the unequal sharing of electrons and water's V-like shape make it a polar molecule -overall charge is unevenly distributed: the oxygen is partially negative, and the hydrogen is partially positive -the properties of water arise from the attractions between oppositely charged atoms of different water molecules

enzymatic proteins

-they regulate metabolism by acting as catalysts -can be thought as workhorses that keep cells running by carrying out the processes of life

cohesion

-water molecules stay close together as a result of hydrogen bonding -at any given moment, water molecules are linked by multiple h-bonds -cohesion contributes to the transport of water and dissolved nutrients against gravity in plants -Ex) as water evaporates from a leaf, hydrogen bonds cause water molecules leaving the veins to tug on molecules farther down, and the upward pull is transmitted through the water-conducting cells all the way to the roots

pure water potential

0

phosphorylation cascade

1) relay molecule activate protein kinase 1 2) active protein K1 transfers a phosphate from atp to an inactive molecule of protein K2, thus activating second kinase 3) active protein K2 then catalyzes the phosphorylation (+activation) of protein K3 4) finally a protein k3 phosphorlyates a protein that brings about the cells response to the signal 5) enzyme called phosphatases catalyze the removal of the phosphate groups from the protein making them inactive and available for reuse

testosterone (hydrophobic hormone) interacting with an intracellular receptor

1) the steroid hormone testoterone passes through the plasma mem 2) testosterone binds to a receptor protein in the cytoplasm, activating it 3) the hormone-receptor complex enters the nucleus and binds to specific genes 4) the bond protein stimulates the transcription of the gene in mRNA 5) the mRNA is translated into a specific protein

benefits of multistep pathways

1.) amplify the signal (and thus the response) 2.) contribute to the specificity of the response

Net energy yield from glycolysis

2 ATP and 2 NADH per glucose molecule

water molecule

2 slightly positive hydrogen atoms, and one slightly negative oxygen atom. The oxygen and hydrogen are held together by covalent bonds and water molecules can bond together with hydrogen bonds.

# of chromosomes in gametes

23 chromosomes

# of chromosomes in human somatic cells

46 chromosomes, made up of two sets of 23 (one from each parent)

Direction of DNA elongation

5' to 3' (starts at the 3' end of a primer)

TATA box

A DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex.

G protein

A GTP-binding protein that relays signals from a plasma membrane signal receptor, known as a G protein-coupled receptor, to other signal transduction proteins inside the cell.

replication fork

A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are being synthesized

protein

A biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure.

microfilament

A cable composed of actin proteins in the cytoplasm of almost every eukaryotic cell, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction; also known as an actin filament.

malignant tumor

A cancerous tumor containing cells that have significant genetic and cellular changes and are capable of invading and surviving in new sites. Malignant tumors can impair the functions of one or more organs.

fatty acid

A carboxylic acid with a long carbon chain. Fatty acids vary in length and in the number and location of double bonds; three fatty acids linked to a glycerol molecule form a fat molecule, also known as a triacylglycerol or triglyceride. -has a long carbon skeleton (around 16-18 C in length)

cooperativity

A kind of allosteric regulation whereby a shape change in one subunit of a protein caused by substrate binding is transmitted to all the other subunits, facilitating binding of additional substrate molecules to those subunits.

spliceosome

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons.

proteoglycans

A large molecule consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells. A proteoglycan may consist of up to 95% carbohydrate.

alternation of generations

A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.

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.

fat

A lipid consisting of three fatty acids linked to one glycerol molecule; also called a triacylglycerol or triglyceride.

phospholipids

A lipid made up of a glyerol joined to two fatty acids and a phosphate group; has two hydrophobic tails and a polar, hydrophilic head -when added to water, they self-assemble into a double-layered sheet called a bilayer

flagella

A long cellular appendage specialized for locomotion, formed from a core of nine outer doublet microtubules and two inner single microtubules, ensheathed in an extension of plasma membrane.

enzyme

A macromolecule serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction. (THEY CANNOT CHANGE THE FREE ENERGY FOR A REACTION)

benign tumor

A mass of abnormal cells with specific genetic and cellular changes such that the cells are not capable of surviving at a new site and generally remain at the site of the tumor's origin.

vacuole

A membrane-bounded vesicle whose specialized function varies in different kinds of cells. -selestive in transporting solutes

cell plate

A membrane-bounded, flattened sac located at the midline of a dividing plant cell, inside which the new cell wall forms during cytokinesis.

food vacuoles

A membranous sac formed by phagocytosis of microorganisms or particles to be used as food by the cell.

photorespiration

A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide.

catabolic pathway

A metabolic pathway that releases energy by breaking down complex molecules to simpler compounds. (EX cellular respiration) "downhill"

feedback inhibition

A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

stomata

A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant. (carbon dioxide enters, oxygen exits)

5' cap

A modified form of guanine nucleotide added onto the nucleotide at the 5' end of a pre-mRNA molecule.

meiosis

A modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication. It results in cells with half the number of chromosome sets as the original cell.

phosphorylated intermediate

A molecule (often a reactant) with a phosphate group covalently bound to it, making it more reactive (less stable) than the unphosphorylated molecule. (key to coupling exergonic and energonic reactions)

organic molecules

A molecule containing carbon that is a part of or produced by living systems.

ligand

A molecule that binds specifically to another molecule, usually a larger one.

ligand

A molecule that binds specifically to another molecule, usually a larger one. ex) LDLs

insertion

A mutation involving the addition of one or more nucleotide pairs to a gene. (disastrous effects)

nonsense mutation

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

deletion

A mutational loss of one or more nucleotide pairs from a gene. (disastrous effects)

nuclear lamina

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

Cytoskeleton

A network of microtubules, microfilaments, and intermediate filaments that branch throughout the cytoplasm and serve a variety of mechanical and transport functions. -very important to animal cells which lack walls

introns

A noncoding, intervening sequence within a primary transcript that is removed from the transcript during RNA processing; also refers to the region of DNA from which this sequence was transcribed.

virus

An infectious particle incapable of replicating outside of a cell, consisting of an RNA or DNA genome surrounded by a protein coat (capsid) and, for some viruses, a membranous envelope.

cristae

An infolding of the inner membrane of a mitochondrion that houses the electron transport chain and the enzyme catalyzing the synthesis of ATP.

primary transcript

An initial RNA transcript from any gene; also called pre-mRNA when transcribed from a protein-coding gene.

Cytochromes

An iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells

Plasmodesmata

An open channel in the cell wall of plants through which strands of cytosol connect from adjacent cells, allows wter, small solutes, and some larger molecules to pass between the cells

cell cycle

An ordered sequence of events in the life of a cell, from its origin in the division of a parent cell until its own division into two. The eukaryotic cell cycle is composed of interphase (including G1, S, and G2 phases) and M phase (including mitosis and cytokinesis)

Golgi apparatus

An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum and synthesize some products, notably noncellulose carbs.

amino acid

An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of proteins.

coenzyme

An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions.

monohybrids

An organism that is heterozygous with respect to a single gene of interest. A monohybrid results from a cross between parents homozygous for different alleles. For example, parents of genotypes AA and aa produce a monohybrid genotype of Aa.

dihybrids

An organism that is heterozygous with respect to two genes of interest. All the offspring from a cross between parents doubly homozygous for different alleles are dihybrids. For example, parents of genotypes AABB and aabb produce a dihybrid of genotype AaBb.

endotherm

An organism that is internally warmed by a heat-generating metabolic process

facultative anaerobe

An organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present.

obligate anaerobe

An organism that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it.

trans fat

An unsaturated fat, formed artificially during hydrogenation of oils, containing one or more trans double bonds.

somatic cell

Any cell in a multicellular organism except a sperm or egg cell.

cofactor

Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis

organelle

Any of several kinds of membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells.

allele

Any of the alternative versions of a gene that may produce distinguishable phenotypic effects.

Why cant enzymes digest starch and cellulose?

Becuase of the different shapes of the two molecules

glucose

C6H12O6 - the most common monosaccharide. -the molecule has a carbonyl group (C=O) and multiple hydroxyl groups (-OH) -carbon skeletons ranges from three to seven carbons long

induced fit

Caused by entry of the substrate, the change in shape of the active site of an enzyme so that it binds more snugly to the substrate.

Endocytosis

Cellular uptake of biological molecules and particulate matter via formation of new vesicles from the plasma membrane.

cyclic AMP

Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells (for example, in vertebrate endocrine cells). It is also a regulator of some bacterial operons.

pyrimidines

Cytosine and Thymine -nitrogenous bases with a single ring

tertiary structure of a protein

Defined by the hydrophilic and hydrophobic interactions between R groups of amino acid chains.

what is oxygen?

EXTREMELY ELECTRONEGATIVE

how does the chain of carriers in the ETC work?

Each "downhill" carrier is more electronegative than, and thus capable of oxidizing, its "uphill" neighbor, with oxygen at the bottom of the chain.

valence electrons

Electrons on the outermost energy level of an atom

heterochromatin

Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed.

which molecule allows the ETC to provide one-third less energy for atp synthesis

FADH2

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.

ionic bond

Formed when one or more electrons are transferred from one atom to another

which checkpoint is dubbed the "restriction point" and is the most important checkpoint

G1 - if the cell receives the go-ahead signal at this checkpoint, it will usually complete the G1, S, and G2, and M phases and divide

genetic recombination

General term for the production of offspring with combinations of traits that differ from those found in either parent.

alcohol fermentation

Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD+ and releasing carbon dioxide.

lactic acid fermentation

Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide.

Chlorophyll

Green pigment located in membranes within the chloroplasts of plants and algae and in the membranes of certain prokaryotes. chlorophyll a participates directly in the light reactions, which convert solar energy to chemical energy

How to tell if the genes for certain traits are linked?

If the parental types occur more often

nucleic acid probe

In DNA technology, a labeled single-stranded nucleic acid molecule used to locate a specific nucleotide sequence in a nucleic acid sample. Molecules of the probe hydrogen-bond to the complementary sequence wherever it occurs; radioactive, fluorescent, or other labeling of the probe allows its location to be detected.

integrin

In animal cells, a transmembrane receptor protein with two subunits that interconnects the extracellular matrix and the cytoskeleton.

terminator

In bacteria, a sequence of nucleotides in DNA that marks the end of a gene and signals RNA polymerase to release the newly made RNA molecule and detach from the DNA.

operator

In bacterial and phage DNA, a sequence of nucleotides near the start of an operon to which an active repressor can attach. The binding of the repressor prevents RNA polymerase from attaching to the promoter and transcribing the genes of the operon.

hybridization

In genetics, the mating, or crossing, of two true-breeding varieties.

secondary cell wall

In plant cells, a strong and durable matrix that is often deposited in several laminated layers around the plasma membrane and provides protection and support. (this is added after the cell matures and stops growing... it wants to strengthen its cell wall)

primary cell wall

In plants, a relatively thin and flexible layer first secreted by a young cell.

middle lamella

In plants, a thin layer of adhesive extracellular material, primarily pectins, found between the primary walls of adjacent young cells.

mesophyll

Leaf cells specialized for photosynthesis. In C3 and CAM plants, mesophyll cells are located between the upper and lower epidermis; in C4 plants, they are located between the bundle-sheath cells and the epidermis.

flaccid

Limp. Lacking turgor (stiffness or firmness), as in a plant cell in surroundings where there is a tendency for water to leave the cell. (A walled cell becomes flaccid if it has a higher water potential than its surroundings, resulting in the loss of water.) isotonic surrounding

homologs

Matching Chromosomes that are similar but not identical (parental vs maternal)

catabolism

Metabolic pathways that break down molecules, releasing energy.

RNA processing

Modification of RNA primary transcripts, including splicing out of introns, joining together of exons, and alteration of the 5' and 3' ends.

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.

F2 generation

Offspring resulting from interbreeding of the hybrid F1 generation.

plastid

One of a family of closely related organelles that includes chloroplasts, chromoplasts, and amyloplasts (leucoplasts). Plastids are found in cells of photosynthetic organisms.

A site

One of a ribosome's three binding sites for tRNA during translation. The A site holds the tRNA carrying the next amino acid to be added to the polypeptide chain. (A stands for aminoacyl tRNA.)

E site

One of a ribosome's three binding sites for tRNA during translation. The E site is the place where discharged tRNAs leave the ribosome. (E stands for exit.)

siRNA

One of multiple small, single-stranded RNA molecules generated by cellular machinery from a long, linear, double-stranded RNA molecule. The siRNA associates with one or more proteins in a complex that can degreade or prevent translation of an mRNA with a complementary sequence.

enantiomers

One of two compounds that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon. Usually only one isomer is biologically active because only that form can bind to specific molecules in an organism

structural isomers

One of two or more compounds that have the same molecular formula but differ in the covalent arrangements of their atoms. They may also differ in the location of double bonds.

isomers

One of two or more compounds that have the same numbers of atoms of the same elements but different structures and hence different properties.

purine

One of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring fused to a five-membered ring. Adenine (A) and guanine (G) are purines.

pyrimidine

One of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring. Cytosine (C), thymine (T), and uracil (U) are pyrimidines.

Example of growth factor

PDGF is a growth factor that when it binds to certain receptors it triggers a signal transduction pathway that allows the cells to pass the G1 checkpoint and divide

trisomic

Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two.

isotonic

Referring to a solution that, when surrounding a cell, causes no net movement of water into or out of the cell.

hypertonic

Referring to a solution that, when surrounding a cell, will cause the cell to lose water.

hypotonic

Referring to a solution that, when surrounding a cell, will cause the cell to take up water.

rubisco

Ribulose bisphosphate (RuBP) carboxylase-oxygenase, the enzyme that normally catalyzes the first step of the Calvin cycle (the addition of CO2 to RuBP). When excess O2 is present or CO2 levels are low, rubisco can bind oxygen, resulting in photorespiration.

What phase takes the most time?

S phase

paracrine signaling

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

origins of replication

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

template strand

The DNA strand that provides the pattern, or template, for ordering, by complementary base pairing, the sequence of nucleotides in an RNA transcript.

Pleiotropy

The ability of a single gene to have multiple effects. ex) cystic fibrosis and sickle-cell disease

substrate-level phosphorylation

The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.

differential gene expression

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

telophase

The fifth and final stage of mitosis, in which daughter nuclei are forming and cytokinesis has typically begun.

meiosis I

The first division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell.

F1 generation

The first filial, hybrid (heterozygous) offspring arising from a parental (P generation) cross.

G1 phase

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

light reactions

The first of two major stages in photosynthesis. These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process.

cleavage furrow

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

prophase

The first stage of mitosis, in which the chromatin condenses into discrete chromosomes visible with a light microscope, the mitotic spindle begins to form, and the nucleolus disappears but the nucleus remains intact.

double helix

The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape.

anaphase

The fourth stage of mitosis, in which the chromatids of each chromosome have separated and the daughter chromosomes are moving to the poles of the cell.

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. (CARBS!)

asexual reproduction

The generation of offspring from a single parent that occurs without the fusion of gametes (by budding, division of a single cell, or division of the entire organism into two or more parts). In most cases, the offspring are genetically identical to the parent.

genotype

The genetic makeup, or set of alleles, of an organism.

genome

The genetic material of an organism or virus; the complete complement of an organism's or virus's genes along with its noncoding nucleic acid sequences.

carbon fixation

The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote).

Extracellular matrix

The meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by the cells.

active transport

The movement of a substance across a cel membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins.

receptor-mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances. ex) humans taking in cholesterol

phenotype

The observable physical and physiological traits of an organism, which are determined by its genetic makeup.

solute potential

This measurement has a maximum value of 0; it decreases as the concentration of a solute increases.

only viable human monosomy

Turner syndrome - XO

What holds back the flood of electrons to a lower energy state?

activation energy

what can even a slight change in primary structure do?

affect a proteins shape and ability to function

secondary structure of a protein

alpha helix and beta pleated sheet - result of hydrogen bonding between the repeating constituents of the polypeptide backbone (not the AA side chains)

regulator

an animal for which mechanisms of homeostasis moderate internal changes in a particular variable in the face of external fluctuation of that variable

DNA polymerases

an enzyme that catalyzes the elongation of new DNA by the addition of nucleotides to the 3' end of an existing chain (usually require a primer and a dna template)

character

an observable heritable feature that may vary among individuals

Peroxisomes

an organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen, producing and then degrading hydrogen peroxide

chloroplasts

an organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water

mitochondria

an organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP

conformer

animal for which an internal condition conforms to changes in an environmental variable

lipid

any of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water

amine group

basic

cells

basic structural and functional units of every organism

most animal and plant cells are how big in diameter

between 10 and 100 micrometers

peptide bond

bond between amino acids -carboxyl group of one protein is adjacent to the amino group of the other, they join by dehydration reaction resulting in a covalent bond aka peptide bond

nucleotides

building blocks of nucleic acids - a nitrogenous base, a five-carbon sugar, and one to three phosphate groups

monomers

building blocks of polymers

what can excessive leakage from a large number of lysosomes do?

can destroy a cell by self-digestion

three steps of calvin cycle

carbon fixation, reduction, regeneration

functional group examples

carboxyl, amino, phosphate, and methyl group

three types of work a cell does

chemical, transport, mechanical

autosome

chromosome that is not a sex chromosome

Proto-oncogenes

code for proteins that stimulate normal cell growth and division

properties of water

cohesion, adhesion, high specific heat, surface tension, capillary action, polar

structure of plasma membrane

consist of bilayer of phospholipids with various proteins attached or embedded in it

disaccharide

consists of two monosaccharides joined by a glycosidic linkage

carbohydrate and protein polymers are synthesized by what reactions?

dehydration reactions

dna sequencing

determining the order of nucleotide bases in a gene or dna fragment

variation

differences between members of the same species

hunt morgan

discovered gene linkage

cytokinesis

division of the cytoplasm to form two separate daughter cells immediately after mitosis

How does a cell grow during interphase?

during all three phases, the cell grows by producing proteins and cytoplasmic organelles such as the mitochondria and ER.

monomer of lipids

fatty acids and glycerol

what is the difference between a first and second messenger

first = extracellular signaling molecules

Law of Segregation

first law of heredity stating that pairs of alleles for a trait separate when gametes are formed

reception

first step - the binding of a signaling molecule to a receptor protein, activating the receptor by causing it to change shape

carbon chains for,mwhat in most organic molecules?

form the skeletons and the skeletons can vary in length and may be branched, straight, or in closed rings. This variation is important source of molecular complexity and diversity that characterize living matter.

intracellular receptor proteins

found in the cytoplasm or nucleus of target cells, they bond to chemical messengers that are hormones or very small, like nitric oxide

How many bonds does carbon form?

four covalent bonds because it has four valence electrons in a shell that can hold up to eight electrons so it completes its shell by sharing its four electrons with other atoms so that eight are present. This enables carbon to form large, complex molecules

linked genes

genes located close enough together on a chromosome that they tend to be inherited together -usually seen with a higher proportion of offspring with traits seen in the P generation

Oncogenes

genes that cause cancer by blocking the normal controls on cell reproduction

Stages of Cellular Respiration

glycolysis, the citric acid cycle, and oxidative phosphorylation (ETC and chemiosmosis)

Autonomous organelles

grow and reproduce within the cell (ex - mitochondria and chloroplast)

amphipathic

having both a hydrophilic region and a hydrophobic region (phospholipids are this)

simplest organic molecule

hydrocarbon

bonds between nucleotides

hydrogen bonds

what are the four main elements of organic molecules?

hydrogen, oxygen, nitrogen, and carbon

How do we digest food?

hydrolysis

epigenetic inheritance

inheritance of traits transmitted by mechanisms that do not involve the nucleotide sequence (why one identical twin acquires a genetically based disease, but the other does not)

how is the chemical nature of a protein determined?

it is determined by the kind and sequence of the side chains (backbone of R groups), which determine how a polypeptide folds and thus its final shape

Why is SA:Volume ratio especially important in some cells?

it is especially important in cells that exchange a lot of material with their surroundings, such as intestinal cells. these cells may have long thin projections from their surface called microvilli

Why do cells divide

it is how single celled organisms reproduce and it is essential for growth and development and tissue renewal

for a system to reach equilibrium, G is at...

its lowest possible value in that system

thermal energy

kinetic energy due to the random motion of atoms and molecules; energy in its most random form

denaturation

loss of normal shape of a protein due to heat or other factor

distal control elements (enhancers)

may be far away from a gene or even located in an intron, but are more specific to certain genes

inorganic molecules

molecules that do not contain carbon

Carbohydrates monomer

monosaccharides

The simplest carbohydrates are

monosaccharides

how are ribosomes and rate of protein synthesis related?

more ribosomes in a cell = higher rates of protein synthesis

what must happen to a disaccharide before it is used for energy?

must be broken down into a monosaccharide

dimers

pairs of molecules connected by two hydrogen bonds

local regulators

paracrine and synaptic (used for local signaling)

R group (side chain)

part of amino acid that determines the molecule's physical and chemical properties

Basic features of all cells

plasma membrane, cytosol, chromosomes, ribosomes

smooth er

portion of er that is free of ribosomes -functions in diverse metabolic processes like synthesis of lipids, metabolism of carbs, detoxification of drugs and poisons, and storage of calcium ions

cohesins

protein complexes that hold sister chromatids together -this attachment is known as sister chromatid cohesion

transcription factors

proteins that control which genes are transcripted into mRNA in a cell at a particular time

Three stages of cell signaling

reception, transduction, response

monosomic

referring to a diploid cell that has only one copy of a particular chromosome instead of the normal two

mutlifactorial

referring to a phenotypic character that is influenced by multiple genes and environmental factors

true-breeding

referring to organisms that produce offspring of the same variety over many generations of self-pollination

antiparallel

referring to the arrangement of the sugar-phosphate backbones in a DNA double helix (they run in opposite 5' -3' directions).

antiparallel

referring to the arrangement of the sugar-phosphate backbones in a dna double helix (they run in opposite 5'-3' directions)

osmoregulation

regulation of solute concentrations and water balance by a cell or organism ex) Paramecium caudatum has contractile vacuoles to deal with the constant entering of water into the cell

dehydrogenases

remove hydrogen atoms

main difference between living and nonliving things

reproduction - continuity of life!

sexual reproduction

reproduction arising from fusion of two gametes

sites of protein synthesis

ribosomes

transduction

second step- a step or series of steps that converts the signal to a form that can bring about a specific cellular response. - usually requires a sequence of changes in a series of different molecules—a signal transduction pathway.

rna transcription

the synthesis of RNA using DNA as a template

when a reaction has less free energy...

the system in its final state is less likely to change and is therefore more stable than it was previously (more free energy

autocrine signaling

the target cell is also the secreting cell

heredity

the transmission of traits from one generation to the next

fertilization

the union of haploid gametes to produce a diploid zygote.

example of diffusion

the uptake of oxygen by a cell performing cellular respiration

heat

thermal energy in transfer from one body of matter to another

Why are lipids hydrophobic?

they consist mostly of hydrocarbons, which form nonpolar covalent bonds

response

third step - the change in a specific cellular activity brought about by a transduced signal from outside the cell

repressible operon

transcription is usually on, but can be inhibited (repressed) when a specific small molecule binds allosterically to a regulatory protein (example tryptophan)

functions of membrane proteins

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to the cytoskeleton and ECM

inducible operon

usually off, but can be stimulated (induced) when a specific small molecule interacts with a regulatory protein (example lac operon)

apoptosis

virus causes lysosomes to burst and then digestive enzymes (hydrolytic enzymes) basically digests the cell (important in maintaining the regular functions and activities of cells)

which direction does water move (water potential)

water moves from areas of high water potential to low water potential

hydrogen bond

weak attraction between a hydrogen atom and another atom