Killian Biology Semester 2
What is "Darwinian fitness"?
"Darwinian fitness" refers to surviving to reproductive age.
Outline the typical life-cycle of a mushroom, using proper terminology like basidia, spores, sporangia, mycelium, zygote, hyphae, and fruiting body.
*Nuclei within the BASIDIA fuse to form diploid zygotes *The ZYGOTES undergo meiosis to form haploid spores *The SPORES drop from the gills and are carried away by wind or contact from animals *If the spores land in a favorable environment, they grow and form haploid HYPHAE (SPORANGIA may grow, which are spore-forming structures at the tips of the hyphae) *Some cells of the haploid MYCELIUM may fuse with the cells of another haploid mycelium, producing a diploid mycelium underground *An environmental cue, such as rain or a change in temperature, can trigger the formation of aboveground FRUITING BODIES such as mushrooms
The origin of life on Earth: Hypothesis
*The Big Bang Theory -all matter was concentrated and a "big bang" blew it all apart -15 billion years ago -when earth formed it was hot and contained little to no oxygen -4.5 billion years ago -earliest life forms: probably heterotrophic; RNA was probably the first genetic material because it can catalyze other reactions -3.5 billion years ago -"oxygen revolution" --> with increased oxygen from photosynthesizers, the ozone layer probably formed; led to increased reliance on photosynthesizers -2.5 billion years ago
Human Genome Project
*goals: -map and sequence DNA base pairs of all 24 human chromosomes (finished in 2003) -identify all genes within a sequence *current work: -identifying genes -locating genes on chromosomes -determining gene function
Mendelian genetics
*homozygous: having two of the same allele (AA or aa) *heterozygous: having two different alleles (Aa) *dominance: occurs when an allele masks the presence of another allele of the same gene (A) *recessiveness: occurs when an allele is masked in a heterozygous organism (a) *X-linked traits: traits that are present on the sex chromosomes
List two possible benefits from genetic engineering.
Two possible benefits to genetic engineering include the hypothetical synthesis of individualized medication and xenotransplantation, or the transplant of organs from members of one species to members of another. Xenotransplantation could hypothetically be used to transfer the liver of a pig to a human in need of a liver transplant.
Are viruses living entities? Support your answer with a clear argument.
Viruses act as agents of disease, disrupting the normal cell functioning and sometimes even killing the cell. They may also act as agents of heredity, causing permanent inheritable damages. However, viruses are NOT LIVING ENTITIES. This is because they cannot reproduce themselves, and instead can only reproduce copies of themselves inside a living organism. Also, they do not have a metabolism of their own and they do not have cell organelles.
Is Woese's designation of Archaea as a kingdom separate from Monera more like a phonetic classification, or a clasdistic classification? Support your answer with reasons.
Woese's design of Archaea as a kingdom separate from Monera is like a cladistics classification because it focuses on the species ancestry
How does the inheritance of X-linked traits differ from that of other traits?
X-linked traits are located on the sex chromosomes (X or Y), and can only be expressed if a particular chromosome is inherited (i.e. a gene on the Y chromosome cannot be expressed if the organism is female and does not have a Y chromosome).
Cartilage
a flexible connective tissue that is found in between your bones; cushions your bones and allows for smooth movement; also found between neighboring bones that move relative to each other; part of SKELETAL SYSTEM
Ligament
a long, flexible band of connective tissue that connects two bones across a point; part of the SKELETAL SYSTEM
Spinal cord
a rope-like bundle of neurons; connects the brain to the nerves that are found throughout the body; delivers messages to proper muscles; controls involuntary movements, or reflexes; part of the NERVOUS SYSTEM
Bladder
a saclike organ that can store up to half a liter of urine at one time; part of EXCRETORY SYSTEM
Sarcomere
a section of a myofibril that contains all of the filaments necessary to make that section of the muscle contract; part of MUSCULAR SYSTEM
Ureter
a tube that carries urine from each kidney to the bladder; part of the EXCRETORY SYSTEM
Mutations
any random, permanent change in the DNA molecule; many are harmful, some have no effect, and a few actually benefit the organism -nature selects those mutations that are beneficial or adaptive in organism to help shape the course of evolution *raw material for evolution
production of sperm
begins when hormones from the hypothalamus stimulate the pituitary to release FSH and LH, which circulate to the testes *Testes begin releasing testosterone, which causes specialized cells to go through meiosis and become mature sperm; sperm cells fully mature in the epididymus (haploid) *each sperm has a head (contains nucleus and acrosome: allows sperm to penetrate egg), mid-piece(holds mitochondria that supply sperm with ATP for energy needs), and tail (propels sperm from the vagina to the fallopian tubes) -XX=female, XY=male *father's sperm determines sex of offspring
zygote
cell that forms when a male gamete fertilized a female gamete
Epididymis
coiled tube through which sperm leave the testes and enter the vas deferens
Human digestive system:
collection of organs that breaks down food into energy that can be used in cells -digestion is the process by which large complex molecules in food are broken down into smaller molecules that can be used in the body -major organs in this process include: mouth, esophagus, stomach, pancreas, liver, gallbladder, large intestines, small intestines, rectum and anus
Fingernail
dense layers of dead cells that protect fingers from injury; made of keratin (a tough, waterproof protein that gives the ability for nails for grow away from the body but still maintain their shape and sturdiness); part of INTEGUMENTARY SYSTEM
Sexually transmitted diseases
diseases passed from one person to another during sexual contact -bacterial STDs *attack the reproductive organs *can cause infertility *most can be treated with antibiotics *chlamydia, syphilis, gonorrhea -viral STDs *no cure *medications can help control symptoms *hepatitis B, genital herpes, HPV, HIV, AIDS
vas deferens
duct in which sperm mixes with other fluids before reaching the urethra (prostate gland, which surrounds the urethra, produces a fluid that helps sperm move more easily; bulbourethral gland and seminal vesicle secrete semen
First trimester
embryonic stem cells undergo determination and differentiation to form the many specialized tissues and organs *heart begins beating *vertebrae and spinal cord begin to form *brain is developing *many internal organs have appeared *the legs and arms are evident *at 9 weeks the embryo is considered a fetus
Third Trimester
fetus grows to its largest size (average 7- 9 lbs. and around 20in.) *lungs are strengthened as the fetus sucks in and pushes out amniotic fluid
Spleen
filters and cleans the lymph of cell fragments and abnormal tissue; contains many lymphocytes and other white blood cells that destroy harmful bacteria and foreign organisms; part of the LYMPHATIC SYSTEM
Liver
filters blood; produces bile to help digest fats; part of the DIGESTIVE SYSTEM
Gene linkage
genes are said to be linked when they are found close together on a chromosome; generally inherited together; linked genes do not always remain together; the farther apart on a chromosome, the more likely to be independently inherited
Sweat glands
glands in the dermis that protect your body; also known as eccrine glands; produce sweat that prevents damage that might occur when a person moves; found all over the body; help control body temperature; part of the INTEGUMENTARY SYSTEM
Actin [filaments]
hin protein fibers that are pulled to cause muscle contraction; ends are anchored to the sarcomere by a plate of structural protein called a Z line; part of the MUSCULAR SYSTEM
Virus
infectious agent that contains a nucleic acid (either DNA or RNA) and protein coat (capsid) - common virus *Bacteriophage (phage): virus that preys on bacteria
Arteries
large blood vessels that carry blood away from the heart; carry oxygen-rich blood; part of the CIRCULATORY SYSTEM
Pancreas
lies between the stomach and intestines; makes digestive enzymes and hormones that regulate how much glucose the body stores and uses; produces insulin and glucagon; part of the ENDOCRINE SYSTEM
Myofibril
long strands of protein found within a muscle fiber; contains a complex set of filaments that are arranged in a regular pattern; part of MUSCULAR SYSTEM
Trachea
long structure made of soft tissue that connects the mouth and nose to the lungs in humans; also known as the "windpipe"; widens with each breath in; rests with each breath out; divides into two primary bronchi; part of the RESPIRATORY SYSTEM
Small intestines
long, narrow tube in which most digestion takes place; part of the DIGESTIVE SYSTEM
Thymus
makes hormones that cause white blood cells to mature; stimulates white blood cells to fight off infection; part of the LYMPHATIC SYSTEM
production of eggs, or ova
occurs before the female is born *at puberty, every 28 days or so, an increase in FSH stimulates a potential egg to complete meiosis I (ovulation)-23 chromosomes from mother (if fertilized, 23 chromosomes from father)
-testis (plural: testes)
organ of the male reproductive system that produces sperm
Kidney
organs that eliminate waste by filtering and cleaning the blood to produce urine; part of the EXCRETORY SYSTEM
infertility
persistent condition in which offspring cannot be produced
Ovary
produces hormones, such as estrogen and progesterone, that cause sexual maturation (including egg production), influences female characteristics (such as fat distribution and widening of the hips), and causes menstruation; part of the REPRODUCTIVE SYSTEM
Myosin [filaments]
protein fibers that pull actin; anchored to the middle of the sacromere at the M line; part of the MUSCULAR SYSTEM
Cell cycle
regular pattern of growth, DNA duplication, and cell division that occurs in eukaryotic cells
Taxonomy
science of classifying and naming organisms -taxon: level within the Linnaean system of classification that is organized into a nested hierarchy *Domain -three domains: bacteria, archaea, and eukarya *Kingdom -six kingdoms=animalia, plantae, protista, archaea, bacteria, fungi *Phylum *Class *Order *Family *Genus *Species
-menstrual cycle
series of changes in the female reproductive system that takes place over the course of one month causes the egg and follicle to mature 1)flow phase- endometrium detaches from the uterine wall and blood, mucus, and tissue are expelled through the vagina to the outside of the body 2) follicular phase: day 6 to day 14; rise in FSH and LH causes ovulation (day 14); as egg is developing, follicle releases estrogen-causes endometrium to thicken 3) luteal phase: empty follicle turns yellow and is called the corpus luteum; corpus luteum releases estrogen and progesterone, which limits the production of LH and increases the number of blood vessels in the endometrium; if egg is not fertilized, uterine lining begins to shed (flow phase)
Vertebrae
serious of small bones in the backbone; part of the SKELETAL SYSTEM
scrotum
skin that encloses the testes outside of the male body -epididymis: coiled tube through which sperm leave the testes and enter the vas deferens
Gallbladder
small organ that stores bile; part of the DIGESTIVE SYSTEM
Lymph node
small rounded structures into which lymphs are collected; filter the lymph and trap bacteria, viruses, fungi, and cell fragments; part of the LYMPHATIC SYSTEM
testosterone
steroid hormone that is found in greater quantities in men than women and contributes to male sexual characteristics and development
What is binomial nomenclature, and what function does it serve?
-Binomial nomenclature: naming system in which each species is given a two- part scientific name (genus and species) *written in italics or underlined *first letter [of first word] capital, second letter [of second word] lowercase -Scientific names are helpful in a number of ways: 1. Genera such as Quercus contain hundreds of species. Many of these species have very similar common names. 2. Allow scientists to talk about particular species without confusion (biology is studied around the world -- one species may have different common names)
Compare and contrast the following three methods of classifying organisms: orthodox classification, phenetics, and cladistics. Which is the preferred method among taxonomists today? Why?
-Cladistics: classification based on common ancestry *cladograms represent derived characters of species -all species above a hashmark share the derived character it represents in the cladogram -node is a place where a branch splits off (represents the most common ancestor shared by a clade) *Snip Rule: whenever you snip a branch under a node, a clade falls off -each clade is rested within the clade that forms just before it -phylogentics: the study of evolutionary relatedness among various groups of organisms -orthodox classification: classification based on organisms' appearances but not on their DNA sequences -pheneics: classification based on phenotypic information
Outline the cell cycle, include the three stages of interphase and the five stages of mitosis
-Gap 1 (G1) *fist stage *cell carries our normal functions *during this, cells increase in size and organelles increase in number *cell spends most of its time in this phase *length of this stage varies by cell type *requires the cell to go through certain "checkpoints" before proceeding through the cell cycle -Synthesis (S) *second stage *continues to carry out normal functions *during this, cell makes a copy of its nuclear DNA *by the end of this phase, the cell nucleus contains 2 complete sets of DNA -Gap 2 (G2) *third stage *cells continue to carry out normal functions *must have an adequate cell size and undamaged DNA before passing through a checkpoint present at this stage -Mitosis (M) *mitosis is the division of the cell nucleus and its contents *Prophase: -DNA and proteins condense in chromosomes *Metaphase: -chromosomes align along the equator *Anaphase: -chromosomes separate to opposite sides *Telophase: -nuclear membranes start to form -chromosomes uncoil -spindle fibers fall apart *cytokinesis is the process that divided the cell cytoplasm -results in 2 identical daughter cells
Define the term homologies and explain why they are important in classification.
-Homologies: state of similarity in structure and anatomical position but not necessarily in function between different organisms indicating a common ancestry or evolutionary origin *Homologous structures indicate common ancestry (through shared structure) in organisms and are therefore important in classifying organisms
Meiosis
-Prophase I *chromosomes condense and organize and matched or homologous chromosomes (one maternal and one paternal in each pair) are physically paired; segments of chromatids can cross over within each chromosome pair -Metaphase I *homologues line up at equator -Anaphase I *homologues separate into 2 groups, with each group having a mixture of maternal and paternal chromosomes -Telophase I *new haploid nuclei form for 2 new daughter cells -Prophase II *chromosomes condense -Metaphase II *chromosomes line up at equator -Anaphase II *chromatids of each chromosome are separated -Telophase II *each daughter cell from Meiosis I will form 2 more cells for a total of 4 cells
Structure of DNA
-double helical structure -provides code for proper assembly of proteins -contains thymine, guanine, cytosine, and adenine
Summarize the pressure-flow hypothesis. Be sure to include its purpose and the tissue type with which it is associated.
-explains how food, or sap, moves through a plant -states that phloem sap can move in any direction depending on the plant's need -associated with vascular tissue -moves phloem sap from sugar source (any place in a plant that has a high concentration of sugars) to a sugar sink (place where sugar is being used or stored) *these locations change as the plant grows and as the seasons change, thus providing a need for the pressure-flow hypothesis
Function of RNA
-helps build proteins -allows for the transmission of genetic information and protein synthesis
-Sexual reproduction:
-involves the fusion of genetic material (gametes) from 2 parental organism -to ensure the proper chromosomal numbers in the zygote (fertilized egg), each gamete must have half or haploid (N) of the original diploid (2N) amount of DNA -meiosis must occur in order to reduce the chromosome number by half *results in new genetic combinations in the gametes
-Muscle structure:
-made up of myofibril, or long strands of protein found within a muscle fiber -contains a complex set of filaments arranged in a regular pattern *cause muscle contraction -sarcomere (a section of a myofibril that contains all filaments necessary to make that section of the muscle contract -actin [filaments] are thin protein fibers that are pulled to cause muscle contractions *ends of the actin filaments are anchored to the sarcomere by a plate of structural protein (Z line) *when pulled, the drag the ends of the sarcomere along with them -myosin [filaments] are protein fibers that pull actin *anchored to the middle of the sarcomere at the M line *can pull the actin without moving itself
Summarize the cohesion-tension hypothesis. Be sure to include its purpose and the tissue type with which it is associated.
-proposes that the physical properties of water allow the rise of water through a plant -based on the strong attraction of water molecules to one another and to other surfaces -moves water through the the xylem, a type of vascular tissue, in plants without using any metabolic energy -associated with vascular tissue
-Human reproductive systems:
-reproductive system: body system that allows for sexual reproduction *includes testes, ovaries, uterus, and other male and female sex organs *females and males reach sexual maturity, or the ability to produce offspring, only after puberty
Structure of RNA
-single-stranded -assembled as chain of nucleotides -contains adenine, guanine, cytosine, and uracil
Function of DNA
-stores the genetic information for putting amino acids together to make proteins
Linnaean taxonomy (species names)
-two rules *genus name can never be used for any other group *species name cannot be used for any other group in the same genus -example: Tursiops truncatus * Tursiops is the genus * truncatus is the species
Retroviruses
-uses RNA as genetic material -uses the enzyme reverse transcriptase to make a DNA copy -causes a lysogenic infection -examples: HIV
-Muscle function:
-when the muscle is not moving, the actin filaments are far away from the center of the sarcomere -during contraction, myosin filaments pull the actin filaments toward the center and shorten the sarcomere
Determine the age of a fossilized artifact found in a 1 kg sample of rock containing 125 g of carbon-14. Assume the entire kilogram sample was originally carbon-14. Carbon-14's half life is 5730 years.
1 kg = _____g 1 kg = 1,000 g 125 g = 0.125 = 12.5% carbon-14 1,000 g
Using a Punnett square, work out the probable ratios for the phenotypes of offspring from a cross between a homozygous (TT) tall pea plant and a heterozygous (Tt) tall pea plant. (Tall is the dominant condition.)
t t T TT TT t Tt Tt 100% chance of a tall pea plant offspring
Describe the process of DNA replication. Include the roles of the following: DNA polymerase, replication origins, primer, leading strand, lagging strand. Also, describe how replication errors are corrected.
1) Enzymes and other proteins binds to DNA at specific regions (replication origins) 2) Unwinding of double helix a. On the leading strand, DNA polymerase III then catalyzes, or starts, the formation of new DNA strands by adding nucleotides to the RNA primer, beginning the continuous replication of DNA along the leading strand b. On the lagging stand, the DNA is synthesized in short, discontinuous segments (Okazaki fragments) in a 3" to 5" pattern; ligase joins these fragments together 3) Synthesis of a new matching strand for each existing strand -Replication errors are corrected.... 1) DNA polymerase checks DNA, as it replicates, to make sure the resulting base pairs are correct (note that bacterial DNA is "methylated", or a methyl group is added, before replication in order to enable repair enzymes to distinguish the original chain from the possibly incorrect new strand) 2) Excision repair: a. repair endonuclease recognizes mismatch and binds to DNA b. enzyme breaks sugar-phosphate bonds of mismatched section and removes mutant DNA c. DNA polymerase fills deleted DNA sequence d. DNA ligase reconnects replacement piece to neighboring section of original DNA model
Hardy-Weinberg
tendency of a population to maintain a stable frequency *p(squared) + 2pq + q(squared) = 1 -p is the frequency of A; f(A) -q is the frequency of a; f(a) -p(squared) is the frequency of homozygous dominant; f(AA) -q(squared) is the frequency of homozygous recessive; f(aa) -2pq is the frequency of heterozygous; f(Aa) *p + q = 1 *conclusions: 1) allele frequencies remain stable over time; 2) for a given population, one can calculate all genotypic frequencies from allelic frequencies *used to compare real data to model and determine if/how a population is evolving
-Human excretory system:
the body system that eliminates nonsolid wastes through sweat, urine and exhalation to help maintain homeostasis in the body -waste products include toxic materials, excess water, salts, carbon dioxide, urea, minerals, and vitamins -main organs of this system are the skin, lungs, kidneys, ureters, urinary bladder and urethra
Blood types
A and B are the most common blood types; O is the universal "donor"; AB is the universal "receiver"; AB blood type is an example of codominance
What is the difference between a homologous structure and an analogous structure?
A homologous structure refers to organisms with a similar structure, but different functions. An analogous structure refers to a dissimilar structure but similar functions.
What is the composition and role of the mitotic spindle?
A mitotic spindle is made up of spindle microtubules that originate at centrosomes. Centrosomes organize that mitotic spindle throughout cell division, splitting into two during interphase, and moving to opposite poles in the pro-metaphase portion of mitosis.
What is the difference between a polygenic trait and a multifactorial trait?
A multifactorial trait is influenced by both genes and the environment. In contrast, a polygenic trait is influenced by multiple genes, but NOT by the environment.
What are the phagocytes? How do they fight infection?
A phagocyte is a cell that destroys pathogens by surrounding and engulfing them. Phagocytes fight infection by surrounding or engulfing the pathogen. Examples of phagocytes are neutrophils and macrophages.
For what purpose is a restriction enzyme used?
A restriction enzyme is used to cut DNA at precise locations, or restriction sites, based on the nucleotide sequence.
Describe the structure of a virus and its means of infecting cells.
A virus is made up of genetic material surrounded by a capsid, or protein shell. The shape of the capsid, however, can vary from virus to virus. The structure and shape of a virus play a large role in how the viruses work and what cells they infect. Once a virus infects a cell, it can begin reproduction. It is important to remember that viruses are not living and have no structure to maintain; all it carries is what it needs to reproduce-its genes.
What were two advantages and two challenges faced by the first terrestrial plants?
Advantages: *the sunlight was brighter because it was not filtered by water or plankton, so photosynthesis could be carried out more efficiently *the terrestrial atmosphere had more carbon dioxide than the water environment. Disadvantages: *the lack of water lead to the danger of the plants drying out (relied on droplets of water that brought sperm to eggs to produce the next generation of plants) *without the support of the water, there was a need for structural support against gravity.
Immune system
the body system that fights off infection and pathogens -organs involved --> lymphoid organs -skin, stomach acid, etc = 1st line of defense -phagocytes engulf pathogens -T cells destroy infected cells -B cells create antibodies -compliment proteins are made by white blood cells and certain organs -cause invading pathogens to clump -interferons are proteins produced by body cells infected with a virus -final line of defense is the adaptive (learned) immune system -takes long to develop -2 types of immunity -passive: transferred between generations -active: produced by body in response to specific pathogen -antibiotics -treat bacterial infections -antigens are protein markers that help identify foreign cells -memory cells -specialized T and B cells - provide acquired immunity
Cancer
the common name for a class of diseases characterized by uncontrollable cell division; arises when regulation of the cell cycle breaks down; canerous cells can continue to divide without many of the growth factors required for division in healthy cells; come from normal cells that have suffered damage to the genes that help make proteins involved in cell-cycle regulation
List three evolutionary advances that make angiosperms the most successful plant group.
Angiosperms are the most successful plant group because of their evolutionary advances. These flowering plants 1) do not require a great amount of water for fertilization, 2) their embryo is protected because it grows for only a short time and then becomes dormant (enclosed in protective seed), and 3) the sperm is carried in the pollen which makes it greater adapted to terrestrial existence.
-Asexual reproduction:
the creation of offspring from a single parent; does not involve the joining of gametes -most prokaryotes produce through binary fission -other forms of asexual reproduction: *budding *fragmentation *runners *tubers *cuttings *leaflets
What is the difference between an antigen and an antibody? How are they related?
Antigens are protein markers on the surfaces of cells and viruses that help the immune system identify a foreign cell or virus. Antibodies are proteins (made by B cells) that destroy pathogens by making the pathogen ineffective (by binding to the pathogen's membrane proteins), causing pathogens to clump to make them easier for phagocytes to engulf and destroy, or activating complement proteins that weaken the pathogen's cell membrane. Antigens and antibodies are related in that antibodies recognize pathogens, or foreign invaders, by their antigens. Thus, antigens allow antibodies to recognize the incoming pathogens and provide a defense.
Early embryonic development
the fertilized egg implants into the uterus and is nourished by the placenta -zygote continues to undergo cell division until a hollow ball of cells, or blastula is formed -cells on the surface attach to the uterine lining and three layers of cell develop (the ectoderm, the mesoderm, and the endoderm) *ectoderm becomes the skin and nervous system *mesoderm forms many of the internal tissues and organs *endoderm forms the digestive system and the digestive lining. *Once these structures begin to form, the ball of cells is considered an embryo -zygote will undergo development for three trimesters, or periods of around three months each
Nephron
the individual filtering unit of a kidney; about 1 million in a kidney; part of the EXCRETORY SYSTEM
Aorta
the large artery into which blood is pumped from the left ventricle; part of the CIRCULATORY SYSTEM
Pericardium
the membrane enclosing the heart; consists of an outer fibrous layer and an inner double layer of serous membrane; part of the CIRCULATORY SYSTEM
Cerebellum
the part of the brain that coordinates movement; helps maintain posture and balance; automatically adjusts your body to help you move smoothly; part of the NERVOUS SYSTEM
Summarize Darwin's theory of evolution by natural selection in three or four statements.
Darwin's theory of evolution by natural selection states that organisms, gradually throughout time, gain or lose characteristics based on usage. Characteristics that allow an organism to successfully survive and reproduce will eventually become more common in a population of that species, thus exercising the theory of natural selection. Darwin hypothesized that evolution, or gradual change in a species, occurred through natural selection.
Discuss the sources and roles of the following hormones in the reproductive cycle of the human female: E
Estrogen (E): produced in the ovaries by the corpus luteum,acts on FSH & LH stimulation beginning of menstrual cycle, it controls the development of female sex characteristics, causing thickening of uterine lining, prevent period during pregnancy
Trace the path of a mouthful of pasta (a carbohydrate) through the digestive tract, identifying in order the various portions of the digestive system it will pass through and what part of the digestive process each will carry out.
First the pasta enters the mouth. Mechanical digestion begins the moment you bite into the sandwich and start chewing. Chemical digestion also occurs when the salivary glands release saliva that moistens the food and contains an enzyme called amylase. Amylase begins the breakdown of complex sugar molecules into sugars. As you swallow the food, the food moves into the esophagus. The food is pushed down the esophagus by peristalsis, which is the rhythmic contractions of the smooth muscles. The pasta next enters the stomach, a muscular sac. Proteins are digested in the stomach. The contractions of the stomach break the food down even more and mixes the food with the stomach's digestive juice. The stomach lining secretes gastric juice containing hydrochloric acid and the digestive enzyme pepsin. The juice kills the bacteria on the food. Pepsin breaks down some chemical bonds between the amino acids in proteins The pasta has now become chyme. Next the pasta moves to the small intestine. The remaining carbohydrates, proteins and fats are digested into the duodenum, the section of small intestine closest to the stomach. The small intestine is a long, narrow tube where most of the digestion takes place. Chemical digestions further breaks down the complex food molecules. Then you will POOP the food out! The pancreas and the liver also help out in the digestive process
-Skeletal system/bones:
the skeletal system is an organ system that includes the bones and the connective tissues that hold the bones together (the human skeleton has 206 bones) -Appendicular skeleton is the part of your skeleton that is adapted to allow the body to move *includes the bones in the limbs that extend from the trunk of your body (legs, arms, feet, and hands) -Axial skeleton is made up of the bones found in the trunk and head of the body (bones in the skull, spine, ribs, and the breastbone) -Cartilage is the flexible connective tissue that is found between your bones *cushions your bones and allows for smooth movement -Bones connect to form joints *allow for different amounts of movement depending on the bone structures they connect *Synovial joints are held together by ligaments, which are flexible bands of connective tissue -Bones are living tissue that produce blood cells and act as a storage bank for minerals
Discuss the sources and roles of the following hormones in the reproductive cycle of the human female: FSH
Follicle Stimulating Hormone (FSH): produced by the pituitary gland, it acts on GnRH stimulation, and it causes egg to resume maturing inside follicle in ovary
How does gel electrophoresis separate DNA fragments from one another?
Gel electrophoresis separates DNA fragments from one another using a electrical current. The current propels the negatively charged DNA molecules to move towards the positive pole. Upon analysis, the largest fragments of DNA were closest to the negatively charged pole, having moved the least. The smallest fragments moved the furthest towards the positively charged pole.
Name the two processes through which genetic drift can occur.
Genetic drift can occur through the bottleneck effect and the founder effect. The bottleneck effect occurs after some event greatly alters a population and the founder effect occurs after a small number of individuals colonize a new area.
Discuss the sources and roles of the following hormones in the reproductive cycle of the human female: GnRH
Gonadotropin (GnRH): produced by the hypothalamus, acts on low levels of E + P, and it stimulates pituitary gland to release FSH & LH
Discuss the sources and roles of the following hormones in the reproductive cycle of the human female: HCG
Human Chorionic Gonadotropin: it is produced by the placenta, it acts on the formation of placental connection, and it stimulates liberal releases of E & P
Describe the roles of DNA, mRNA, tRNA, ribosomes, introns, exons, and amino acids in the process of gene expression. To what do the terms transcription and translation refer?
In eukaryotic cells, there are 3 steps in gene expression: replication, transcription, and translation. These occur at different times. Replication and transcription both occur in the nucleus, whereas translation occurs outside the nucleus. In prokaryotic cells, gene expression has the same three steps but they occur simultaneously in the cytoplasm. DNA replication has three main steps... 1) Enzymes and other proteins binds to DNA at specific regions 2) Unwinding of double helix 3) Synthesis of a new matching strand for each existing strand This process generate more copies of DNA. In transcription in eukaryotic cells, ribosomes are formed in the nucleolus when two ribosomal subunits join together and bind to rRNA. There are three main steps... 1) Initiation: RNA polymerase binds to the promoter region of DNA, or the region located just ahead of the DNA coding segment; protein initiation factors/transcription factors must be present 2) Elongation: RNA polymerase unwinds the DNA double helix to expose the coding section as it moves down the DNA molecule; also an enzyme builds a complementary single-stranded RNA molecule (primary transcript) 3) Termination: RNA polymerase reaches termination region (end of DNA to be transcribed) and the enzyme and newly formed primary transcript are released Transcription in prokaryotes is characterized by promoters (segments that allow the gene to be transcribed), operators (DNA segments that can turn a gene "on" or "off"), and operons (regions of DNA that include a promoter, an operator, and one of more structural genes that code for proteins) NOTE: In RNA processing (the addition, modification, and removal of nucleotides while RNA is in the nucleus), introns (noncoding sections of DNA) are spliced out and exons (coding segments of DNA) will be expressed. These modified molecules bind to proteins to form ribosomal subunits which, in turn form ribosomes. The third step in gene expression is translation which has three stages... 1) Initiation: ribosome attaches to the start codon of mRNA (this requires energy in the form of GTP, or guanosine triphosphate) 2) Elongation: charged tRNA enters the A site, positioning its amino acid so that it may bond to the previous amino acid on the P site, adding to its polypeptide chain; ribosome moves ahead to position next tRNA molecule in A site 3) Termination: stop codon enters the A site and a "release factor" binds the stop codon, triggering tRNA to release the polypeptide chain Transcription refers to the "transcribing" of DNA to the primary transcript (RNA) Translation refers to the "translation" of tRNA to a polypeptide chain
What is the difference between codominance and incomplete dominance?
In incomplete dominance, both alleles at a gene locus are partially expressed, often producing an intermediate phenotype. In codominance, both alleles are completely and equally expressed.
Biological species definition
In order to be in the same species, organisms must be able to produce fertile offspring and be geographically close to one another
Transcription
In transcription in eukaryotic cells, ribosomes are formed in the nucleolus when two ribosomal subunits join together and bind to rRNA. There are three main steps... 1) Initiation: RNA polymerase binds to the promoter region of DNA, or the region located just ahead of the DNA coding segment; protein initiation factors/ transcription factors must be present 2) Elongation: RNA polymerase unwinds the DNA double helix to expose the coding section as it moves down the DNA molecule; also an enzyme builds a complementary single-stranded RNA molecule (primary transcript) 3) Termination: RNA polymerase reaches termination region (end of DNA to be transcribed) and the enzyme and newly formed primary transcript are released Transcription in prokaryotes is characterized by promoters (segments that allow the gene to be transcribed), operators (DNA segments that can turn a gene "on" or "off"), and operons (regions of DNA that include a promoter, an operator, and one of more structural genes that code for proteins)
Of what two organisms is a lichen composed? What role does each of those carry out?
Lichen is composed of two organisms: a fungus and an algae (or a cyanobacterium). The fungus provides the structural framework with its hyphae, while the algae provides the photosynthetic food.
Discuss the sources and roles of the following hormones in the reproductive cycle of the human female: LH
Lutenizing Hormone (LH): produced in pituitary gland, it acts on GnRH stimulation, and it causes rupturing of follicle, releasing egg into fallopian tube
Describe lytic and lysogenic infection by viruses.
Lytic infection: an infection pathway in which the host cell bursts, releasing the new viral offspring into the host's system, where each then infects another cell. * When the viral DNA enters the host cell, it takes over control of the host's DNA, turning on the genes necessary to copy the viral genes * With direction of the viral genes, the host's DNA undergoes transcription and translation to help in the copying of the virus' DNA * Using energy from the host cell, the caspids and viral DNA assemble into new virions. Viral enzymes dissolve the host cell membrane, releasing the virus particles into the host's bloodstream or tissues, while destroying the host cell in the process. Lysogenic infection: a phage combines its DNA into the host cell's DNA * Upon entering the host cell, the viral DNA combines with the host's DNA, forming a new set of genes called a prophage. (Prophage: the phage DNA inserted into the host's cell's DNA) * Prophage is copied and passed to daughter cells, with the host's own DNA, when the host undergoes mitosis. This process doesn't destroy the cell, but changes some of its traits. * After the cell has been copied, the prophage faces two paths: 1. A trigger (such as stress) activates the prophage which then uses the cell to produce new viruses (basically the prophage enters the lytic infection cycle) or 2. The prophage remains as a permanent gene. NOTE: both lytic and lysogenic have infections have the same first 2 steps: 1) the bacteriophage attaches and injects its DNA into the host bacterium and 2) the viral DNA forms a circle (after this point, the virus may either enter into the lysogenic cycle or stay in the lytic cycle)
Bronchi
the two branches of the trachea that go into the lungs and further divide into bronchioles and alveoli; part of RESPIRATORY SYSTEM
Describe the experiment carried out by Stanley Miller and Harold Urey. You may have to draw a picture of their apparatus. What did their experiment demonstrate?
Miller and Urey worked together to model the conditions that they believed existed on early Earth. Their experiment demonstrated that organic molecules can be made from inorganic molecules. First, a boiling chamber was used to heat the "ocean" water to produce water vapor. The vapor travelled through a tube to the "atmosphere". Next, an electric spark in a mixture of gases stimulated lightning. Then, simple organic molecules such as amino acids were produced.
What is the difference between evolution and natural selection?
Natural selection is a mechanism of evolution whereby numbers of a population with the most successful adaptations to the environments are most likely to survive and reproduce. Evolution is the idea of gradual change throughout time.
Second Trimester
this is a time of continued development and physical activity *heartbeat can be heard *fetus begins to flex its muscles *uterus expands to 4 or 5 times its original size *toes and fingers are fully formed
Why do nonvascular plants exist only in damp environments?
Nonvascular plants exist only in damp environments. This is because, while vascular plants are able to absorb and hold water (with the help of their roots, vascular tissue, and thick cuticle), non-vascular plants cannot. They have very little resistance to drying, and cannot carry the water harvested from the ground to their aerial parts. As a result, nonvascular plants (such as mosses) grow on surfaces where they can absorb water and nutrients directly. They rely on free-standing water to allow their sperm to swim and fertilize eggs.
Evolution
Organisms, gradually throughout time, gain or lose characteristics based on usage. Characteristics that allow an organism to successfully survive and reproduce will eventually become more common in a population of that species, thus exercising the theory of natural selection. Darwin hypothesized that evolution, or gradual change in a species, occurred through natural selection
Alveoli
tiny, thin-walled structures across which oxygen is absorbed and carbon dioxide is released in the lungs; part of the RESPIRATORY SYSTEM
What is the purpose of polymerase chain reaction (PCR)?
PCR is a vital step in any form of genetic engineering. It rapidly creates billions of copies of the original molecule of DNA to allow for a larger sample size during experimentation.
Plant Structure and Function
Plant tissues are made up of three different cells *parenchyma cells (stores starch, oils, and water) *collenchyma cells (provide support while still allowing the plant to grow), *sclerenchyma cells (the strongest due to their second cell wall hardened with lignin) -Plant organs are made up of three tissue systems *dermal tissue (covers the outside of the plant and protects it) *ground tissue (makes up much of the inside of the plant, provides support, and stores materials) *vascular tissue (transports water, nutrients, and organic compounds to all parts of the plant)
Name and describe one example each of a) a plant-like protist, b) an animal-like protist, and c) a fungus-like protist.
Plant-like protist: Algae is a photosynthetic plantlike protist. Plantlike protists look like plants but do not have roots, stems, leaves, specialized tissues, or the same reproductive structures that plants have. They can be multi-cellular or single-cellular, while plants can only be multi-cellular. Animal-like protist: represent largest number of species in kingdom Protista, they can move around, consume other organisms, and their cells lack chloroplasts. Unlike animals, all are unicellular, while animals are multicellular. Protozoa is an animal-like protist. Fungus-like protists: they recycle nutrients such as carbon and nitrogen back into the soil, and have similar reproductive structures and cycles to fungi but can move during part of their life cycle, while fungi cannot.
Distinguish between pollination and fertilization in plants.
Pollination is simply the transfer of pollen from one plant to another. Fertilization, in contrast, is the joining of the male reproductive organ with the female reproductive organ to produce offspring. Insects and the wind perform the transfer of pollen. Fertilization is what happens AFTER pollination, which results in offspring such as fruit.
Discuss the sources and roles of the following hormones in the reproductive cycle of the human female: P
Progesterone (P): produced in the ovaries by the corpus luteum, acts on the beginning of the menstrual cycle, and it prevents menstrual cycle during pregnancy
Mitosis
Prophase: DNA and proteins condense into tightly coiled chromosomes; nuclear envelope breaks down; centrioles begin to move to oppose poles and spindle fibers form -Metaphase: spindle fibers attach to each chromosome and align the chromosomes along the equator -Anaphase: chromatids separate to opposite sides of the cell -Telophase: nuclear membranes start to form; chromosomes begin to uncoil; spindle fibers fall apart
Describe how sex-linked genes are expressed differently in males and females.
Sex-linked genes are expressed differently in males and in females. The sex-linked traits are located on either the X or Y chromosome, so they can only be expressed if that particular chromosome is present in the organism. For example, if the gene for color-blindness is located on the Y chromosome, the organism will not be color-blind unless it is male.
T-cells
white bood cells, or lymphocytes; destroy body cells that are infected with pathogens; part of the IMMUNE SYSTEM
semen
white substance that contains sperm and fluids produced by sex glands of the male reproductive system basic fluids that help to neutralize the acidity in the urethra and the female's vagina
Thyroid gland
wraps around the trachea on 3 sides; releases hormones which regulate metabolism, growth, and development; part of the ENDOCRINE SYSTEM
How are tendons and ligaments similar? How are they different?
Tendons and ligaments are similar in that they are both connective tissue, they allow flexibility, and they physically connect bones allowing movement. They differ because ligaments usually connect bones to one another, while tendons connect bones to muscle tissue.
Describe the formation and function of the plant embryo, endosperm, seed, and fruit.
The PLANT EMBRYO is formed once the sperm fertilizes the egg. This serves as the basis of the plant. The ENDOSPERM is formed from one of the two cells in the pollen grain. One of these cells divides through mitosis, producing two sperm. One of the sperm fertilizes the egg. The other sperm combines with the polar nuclei in the embryo sac. This cell now has a triploid (3n) nucleus. It will become the endosperm. The endosperm serves as a food supply for the developing plant embryo. The ovule becomes a SEED, which contains an embryo and a nutritious endosperm enclosed by a protective seed coat. A few seeds will fall into the soil, and thus create more plants and restart the cycle. While the seed develops, the surrounding ovary grows into a FRUIT. A fruit is the mature ovary of a flowering plant.
What are the differences between the axial skeleton and the appendicular skeleton?
The appendicular skeleton is the part of your skeleton that is adapted to allow the body to move. It includes the bones in the limbs that extend from the trunk of your body (your legs, arms, feet, and hands). In contrast, the axial skeleton is made up of the bones found in the trunk and head of the body. The bones of the axial skeleton support the weight of the body and protect the internal tissues. These include the 27 bones in the skull, the 33 bones that form the spine, the 12 pairs of ribs, and the breast bone.
What impact can the bottleneck effect have on populations that have rebounded after near extinction?
The bottleneck effect can greatly alter the allele frequencies in populations that have rebounded after near extinction. It may wipe out one trait all together, and a trait that was uncommon before may become the most common trait in the population, depending on what traits the survivors have.
What are the five conditions necessary for populations to remain in Hardy-Weinberg equilibrium?
The five conditions necessary for population to remain in Hardy-Weinberg Equilibrium.... 1) No mutations 2) No migration 3) No genetic drift 4) No artificial/natural selection 5) No nonrandom mating/sexual selection
What is the functional unit of the human excretory system? What are the 3 major functions of this structure?
The kidneys are organs that eliminate wastes by filtering and cleaning the blood to produce urine. -kidneys have three basic functions in maintaining homeostasis 1. They remove waste products from the blood, such as those produced from digestion and cell respiration. 2. They help maintain electrolyte, pH, and fluid balances in the body. 3. They release hormones that help to keep bones healthy, to produce red blood cells and to regulate blood pressure.
How do the actin and myosin filaments work together to cause muscle contractions?
The nervous system stimulates myosin filaments to grab the actin by sending an impulse down a motor neuron into a muscle. The place where the motor neuron attaches is called the neuromascular junction. It is here that the neuron releases neurotransmitters that bind to the receptors on the muscle fiber. The neurotransmitters stimulate calcium ion channels to open, which in turn stimulate the myosin filaments. The myosin filaments have arm-like extensions that grab onto and pull the actin filaments. The myosin filaments continue to pull the actin, until the actin filaments have moved as far to the center as possible. At this point, the sarcomere (a section of a myofibril that contains all of the filaments necessary to make that section of the muscle contract) is shortened due to the actin filaments dragging its end. Once the sarcomere is shortened, the muscle is contracted.
What type of gametes are produced by the following plants: GGRr (green pods and round seeds) and TtYy (tall plants with yellow embryos)?
The plants produce GR (green, round), Gr (green, wrinkled), TY (tall, yellow), Ty (tall, green), tY (short, yellow), and ty (short, green) gametes.
Translation
The third step in gene expression is translation which has three stages... 1) Initiation: ribosome attaches to the start codon of mRNA (this requires energy in the form of GTP, or guanosine triphosphate) 2) Elongation: charged tRNA enters the A site, positioning its amino acid so that it may bond to the previous amino acid on the P site, adding to its polypeptide chain; ribosome moves ahead to position next tRNA molecule in A site 3) Termination: stop codon enters the A site and a "release factor" binds the stop codon, triggering tRNA to release the polypeptide chain