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Class Objectives (Cumulative)

Terms in this set (76)

Give one example of a kinase from glycolysis. What does this enzyme do? (ATP, substrate, high-energy phosphate bond)
phosphofructokinase, a key glycolytic enzyme, which catalyzes the synthesis of fructose-1,6 bisphosphate from fructose-6-phosphate, atp serves as a substrate for the addition of a phosphate to fructose-6-phosphate (this increases potential energy)
Summarize the role of redox reactions in cellular respiration. (reduced carbon, oxidized carbon)
Cellular respiration depends on the reduction of NAD+ to NADH and the oxidation of NADH to NAD+. The NADH are used to fuel a proton pump and create a concentration gradient in the intermembrane space.
ATP can be produced by oxidative phosphorylation and substrate-level phosphorylation. Give a specific example of each during cellular respiration.*
-Electrons from NADH and FADH2 move through a series of proteins called an electron transport chain (ETC). The energy released in this chain of redox reactions is used to create a proton gradient across a membrane; the flow of protons back across the membrane is used to make ATP. Because this mode of ATP production links the phosphorylation of ADP w/the oxidation of NADH & FADH2 it is called oxidative phosphorylation.
-Substrate-level phosphorylation involves an enzyme and a phosphorylated substrate. Substrate-level phosphorylation occurs when an enzyme catalyzes the transfer of a phosphate group from a phosphorylated substrate to ADP, forming ATP
How does NADH store the energy released during glycolysis? (reduction, oxidation, electron)
during glycolysis, most of the energy released from the breakdown of glucose is carried by the electrons attached to NADH, NAD+ is reduced or gains an e- to NADH, glucose is oxidized or loses an e-
Know all the steps of glycolysis that were covered in class. Your focus should be on steps that involve energy transfer from one molecule to the next.
BIO Workbook pg. 18-19
Explain the mechanism of feedback inhibition of phosphofructokinase (ATP, allosteric). How does this regulation help the cell?
In phosphofructokinase, Atp acts as an allosteric regulator, as atp concentration increases, atp binds to the active site and the regulatory site of PnFK, when atp binds to the regulatory site, enzyme conformation changes and lowers reaction rate at the active site
Following glycolysis, where do you find the energy that was initially stored in glucose? Where is most of the glucose energy stored? (ATP, NADH, pyruvate)
Most of the energy is stored in the pyruvate molecules
Draw the citric acid cycle focusing on steps where carbon is lost as CO2 and where energy is extracted in the form of reduced molecules. (Do not memorize chemical structures)
BIO Work Book pg 20
Explain the regulation of the citric acid cycle. (ATP NADH, feedback inhibition)
Reaction rates are high when ATP is scarce, and low when ATP is abundant. ATP regulates the citric acid cycle by binding to the enzyme that combines acetyl-coA and oxaloacetate to prevent the production of citrate (feedback inhibition). NADH regulates the citric acid cycle by binding to the enzyme's active site (competitive inhibition).
Where do glycolysis, the citric acid cycle and electron transport take place and what is the importance of location to each process? (cytoplasm, mitochondria, matrix, intermembrane space, compartmentalization)
-Glycolysis = cytosol
-Citric acid cycle = mitochondrial matrix
-Electron transport = inner membrane and cristae of the mitochondria
ETC reactions take place in the inner membrane and cristae of the mitochondrion
Describe or diagram how the electron transport chain creates a gradient. What proteins are involved and where are they located? How is energy stored in the gradient?
-NADH becomes oxidized and electrons are carried from one complex to the other, complexes i and iv use the potential energy released by the redox reactions to pump protons from the mitochondrial matrix to the intermembrane space
-proteins involved: Q found inside cytochrome, which acts like a shuttle for proteins and completes i-iv
-energy is stored by the build up of H+, which stores potential energy that was originally in glucose
Draw or describe or diagram how the H+ gradient is coupled with ATP synthesis. Understand the experiment (Fig. 9.17) that demonstrated how ATP synthesis is coupled to H+ gradients. (chemiosmotic, proton-motive force)
ATP synthesis requires proton-motive force. The electron transport chain pumps protons across the inner membrane of mitochondria from the matrix to the intermembrane space (H+ gradient). ATP synthase can then use the protons to synthesize ATP from ADP and Pi. This process is called chemiosmosis.
Describe and compare the roles of the inner and outer mitochondrial membranes. (H+ gradient,electron transport)*
The 2 membranes create compartments known as the intermembrane space. This plays an important role in oxidative phosphorylation. Allows the creation of a proton gradient which powers ATP synthase to produce ATP.
What is the total number of ATPs produced by the breakdown of a glucose molecule with and without oxygen present?
-Glycolysis: 2
-Aerobic Respiration: In mitochondria about 29 ATP are produced.
-Fermentation: In cytoplasm ; Muscles produce 2 ATP ; Yeast produce 2 ATP
Every few seconds you inhale O2 and exhale CO2. What is the role of each of these molecules in cellular respiration? (aerobic respiration).
Oxygen functions as an electron acceptor. Creates large amount of potential energy used to generate proton motive force.

aerobic respiration is dependent on the presence of oxygen

CO2 is released as a waste product.
In the absence of O2, how is NAD+ recovered? How does this process differ in fungi (yeast) and animals? (Fermentation, ethanol, lactic acid, CO2)
Regenerates NAD+ by oxidizing stockpiles of NADH. Electrons from NADH are transferred to pyruvate, lactate, or ethanol.

- Animals: Lactic acid fermentation (2 lactate produced)
- Fungi: Alcohol fermentation (2 ethanol and 2 CO2)
Chapter 9 focuses on glucose as an energy source for cells. However, we also eat proteins and fats. How do these molecules provide energy for the cell (glycolysis, glycerol, fatty acids, amino acids, pyruvate, acetyl CoA)*
-Fats: enzymes break down fats to release the glycerol and convert the fatty acids into acetyl CoA molecules. Glycerol can be processed and enter glycolysis. Acetyl CoA enters the citric acid cycle.
-Proteins: once hydrolyzed to their constituent amino acids, enzyme-catalyzed reactions remove the amino (-NO2) groups. The amino groups are excreted in urine as waste. The carbon compounds that remain are converted to pyruvate, acetyl CoA, and other intermediates used in glycolysis and the citric acid cycle.
How do fats enter the respiration reactions (glycolysis, citric acid)? How do proteins enter the respiration reactions?
see group objectives
What events take place during Interphase (I) and during the mitotic phase (M) of the cell cycle?
-Interphase - Most of the time, a cell is in interphase. After a cell has divided, the chromosomes uncoil into long, thin structures (uncondensed or "relaxed" chromatin). During interphase, the cell is either growing and preparing to divide or fulfilling its specialized function in a multicellular individual. Interphase is the combination of G1, S, and G2 phases.
-M phase - M phase has two distinct events: the division of the nucleus and the division of the cytoplasm (cytokinesis). The phases of mitosis occur in M phase - prophase, prometaphase (late prophase), metaphase, anaphase, and telophase.
Understand the experiments in which radioactive nucleotides were used to determine when (during I or M) that DNA replication occurred. (pg. 222, pulse-chase)*
Cells were marked with radioactively labeled thymidine for a short time (pulse-chase approach). Only the cells in S phase would have been labeled because chromosomes are replicated during S phase. They discovered that none of the cells started mitosis immediately; they had to wait several hours. This time lag between the end of the pulse and the beginning of mitosis indicated that another phase occurred between S phase and M phase. Thus, G2 phase was discovered between S phase and M phase.
Distinguish between G1 and G2 phase in terms of length and function. What factors influence the transition from G1 S and from G2M? Which phase (G1 or G2) is more variable in animal cells?
-G1 is approximately twice as long as G2.
-G1 function - Protein synthesis and RNA synthesis resume. The cell grows and matures. Nutrients are stored.
-G2 function - Rapid cell growth and protein synthesis occurs in preparation for mitosis. Correct DNA replication is confirmed before continuing to M phase.
-G1 checkpoint (G1 to S) - A cell in G1 will continue to S phase if cell size is adequate, nutrients are sufficient, social signals (signal molecules from other cells) are present, and DNA is undamaged. If DNA is damaged, the protein P53 will stop the cell cycle.
-G2 checkpoint (G2 to M) - A cell in G2 will continue to M phase if chromosomes have replicated successfully, DNA is undamaged, and activated MPF (M phase-promoting factor) is present.
-G1 phase is highly variable in animal cells.
Contrast fission (in prokaryotes) with mitosis (in eukaryotes).*
Note: Not sure if this is complete. Chromosome segregation and cytokinesis in binary fission is very similar to the eukaryotic M phase. However, binary fission is a much faster process. It does not include spindle formation (mitotic apparatus), and sister chromatids are not produced.
Explain the relationship between the following terms: chromatin, chromatid, chromosome (histones, condense)
-A chromosome is composed of a DNA molecule and associated proteins. Chromatin and chromatid are terms that describe different physical states of a chromosome.
-Chromatin is a DNA molecule and histone proteins in a relaxed, uncoiled state. When chromatin condenses, it forms a chromatid.
-A chromatid is one strand of a replicated chromosome with its associated proteins in a condensed state. When a chromatid relaxes, it becomes chromatin.
You must know the events of Prophase, prometaphase, metaphase, anaphase and telophase. Be able to draw the cell at each stage and explain the important events taking place. Be able to label the following structures: chromatids (sisters or individual), centromere, centrosomes/centriole, kinetochore, nuclear envelope
-Prophase - Chromosomes condense and become visible. Centrosomes (1 centrosome = 2 centrioles) begin to move to opposite sides of the cell and produce microtubules; this begins the formation of the spindle apparatus. Nuclear envelope is still visible.
-Prometaphase - Nuclear envelope breaks down. Microtubules then attach to chromosomes at specialized structures called kinetochores, which are assembled at the centromere. Centrosomes reach opposite ends of the cell.
-Metaphase - Chromosomes complete migration to middle of cell. They are lined up on the metaphase plate. Formation of spindle apparatus is complete.
Anaphase - Sister chromatids separate into daughter chromosomes and are pulled to opposite poles of the spindle apparatus.
-Telophase - The nuclear envelope reforms around each set of chromosomes. Chromosomes de-condense. Mitosis is complete when when two independent nuclei have formed.
How do animal and plant cytokinesis differ?(cell plate, cell wall, cleavage furrow)*
-In animal cells, cytokinesis begins with the formation of a cleavage furrow. The cleavage furrow appears because a ring of actin filaments form just inside the plasma membrane, in the middle of what used to be the spindle. Myosin binds to actin, causing the filaments to contract and shrink until the membrane splits, forming 2 cells.
-Plant cells undergo cytokinesis at the cell plate (instead of the cleavage furrow). The cell plate is made of vesicles that carry components to build a new cell wall in the middle of the dividing cell. When the cell plate fuses with the plasma membrane, the cell splits, forming 2 cells.
What is the role of motor proteins in mitosis? (microtubule, kinetochore)*
During prometaphase, kinesin and dynein (motor proteins) are recruited to the kinteochore, where they can "walk" chromosomes up and down microtubules.
Describe the experiment (Fig. 12.10) that identified the Mitosis Promoting Factor (MPF). What two proteins are now known to make up the MPF?
Researchers noticed that when a cell in M phase was fused with a cell in interphase, the nucleus of the interphase cell immediately initiated mitosis. However, they could not identify if it was the nucleus or the cytoplasm of the M phase cell that caused mitosis in the I phase cell. South African clawed frog cells were used in the experiment because their cells are abnormally large. Cytoplasm from frog eggs in M phase were injected into the cytoplasm of frog oocytes arrested in G2. The G2 cells immediately entered M phase. This process was repeated, but cytoplasm from I phase frog cells were injected. The G2 cell remained in G2. Therefore, a factor must exist that drives the G2 cells (oocytes) to enter M phase. This factor is known as M phase-promoting factor (MPF)
What molecules interact with CDK and what is their effect on cell division? (G2, cyclin, p53, promote division, inhibit division)
-MPF has two components (dimer): cyclin-dependent kinase (Cdk) and a cyclin. Cdk is regulated by two phosphorylation events. Phosphorylation of one site activates the kinase, and phosphorylation of the other site inactivates the kinase. In G2 phase, the site that inactivates the kinase is phosphorylated, which inhibits mitosis and further cell division. Late in G2 phase, the inactivating site is dephosphorylated, and the other site is phosphorylated. A conformational change occurs and activates MPF, which promotes mitosis and further cell division.
-p53 may also bind to Cdk, causing long-term inhibition of cell division.
Compare the G1 and G2 checkpoints of the cell cycle. What conditions are required for passing each checkpoint. (DNA damage, nutrients, DNA replication, signals)*
G1 checkpoint (G1 to S) - A cell in G1 will continue to S phase if cell size is adequate, nutrients are sufficient, social signals (signal molecules from other cells) are present, and DNA is undamaged. If DNA is damaged, the protein p53 will stop the cell cycle.
G2 checkpoint (G2 to M) - A cell in G2 will continue to M phase if chromosomes have replicated successfully, DNA is undamaged, and activated MPF (M phase-promoting factor) is present.
How could malfunction of the cell-cycle control system lead to cancer?*
Regulatory proteins like p53 are called tumor suppressors because they stop the cell cycle when DNA is damaged. If the DNA cannot be repaired, p53 ultimately kills the cell. Damage to genes that regulate cell growth (like p53) can lead to uncontrolled cell division (cancer).
How do autotrophic and heterotrophic organisms differ? To which class of organisms do plants belong?*
Autotrophic organisms (autotrophs) can make all their own food from ions and simple molecules. Heterotrophic organisms (heterotrophs) must obtain sugars and other macromolecules from other organisms. Plants are autotrophic organisms.
What are the reactants of photosynthesis? What are the products? How does the overall reaction of photosynthesis compare to that of respiration? (CO2, H2O, C6H12O6, O2)
-Reactants = CO2 + H2O + light energy
-Products = C6H12O6 (glucose) + O2
-Photosynthesis is an endergonic suite of redox reactions that produce sugars from CO2 and light energy. Cellular respiration is an exergonic suite of redox reactions that produces CO2 and ATP from sugars.
Write the basic chemical reaction for the synthesis of glucose by photosynthesis. Also, draw a simple free energy diagram for photosynthesis with one line for the reactants and one for the products (from the previous objective).
6 CO2 + 6 H2O + light energy >>> C6H12O6 + 6 O2
Diagram: SEE CLASS OBJECTIVES
Note that only the first half is photosynthesis.
Where does the light reaction of photosynthesis take place? (Chloroplast, thylakoid, stroma, membrane)
The light reaction of photosynthesis occurs in chloroplasts. Within a chloroplast are flattened, sac-like structures called thylakoids which often occur in interconnected stacks called grana. The fluid-filled space between the thylakoids and the inner membrane of a chloroplast is the stroma. Photons pass through the chloroplast's inner and outter membranes and into the stroma. The photons then interact with photosystems that are located in the thylakoid membrane. Hydrogen ions are pumped through the thylakoid membrane into the thylakoid lumen.
What is a "photosystem"? (pigment, chlorophyll, electron)
Chlorophyll molecules (a pigment) work in groups, not individually. In the thylakoid membrane, 200-300 chlorophyll molecules and accessory pigments are organized by an array of proteins to form structures called the antenna complex and the reaction center. These complexes, along with the molecules that capture and process excited electrons, form a photosystem.
Chlorophyll molecules (a pigment) work in groups, not individually. In the thylakoid membrane, 200-300 chlorophyll molecules and accessory pigments are organized by an array of proteins to form structures called the antenna complex and the reaction center. These complexes, along with the molecules that capture and process excited electrons, form a photosystem.
-Blue/violet light (450nm) and red light (650 nm) are absorbed the most.
-Green light (550nm) is absorbed the least.
-Chlorophyll molecules and accessory pigments are organized by an array of proteins to form structures called the antenna complex and the reaction center. When a red or blue photon strikes a pigment molecule in the antenna complex, the energy is absorbed and an electron is excited in response. This phenomenon is known as resonance energy transfer. When a chlorophyll molecule is excited in the reaction center, its excited electron is transferred to an electron acceptor. Accessory pigments absorb wavelengths of light that chlorophyll cannot absorb. Therefore, they extend the range of wavelengths that can drive photosynthesis.
In the initial step of the light reaction of photosynthesis, light energy is absorbed creating a high-energy electron. During the remaining steps of photosynthesis what other forms does this energy take? (reduced molecules, chemical bonds, gradients)
NADP+ is reduced to NADPH.
Energy is stored in high-energy phosphate bonds to form ATP from ADP + Pi.
Protons are pumped into the thylakoid lumen, which creates a proton gradient. The flow of protons down the gradient supplies energy to ATP synthase to drive the production of ATP
What is the role of H2O in photosynthesis? (electron)
Water supplies electrons for photosystem II, leaving O2 as a byproduct. This is known as "splitting" water.
In plain words, compare the major events of the light reaction and the Calvin-Benson cycle. What does each component of photosynthesis do for the plant?
(not sure about this one) Photosynthesis stores energy in NADPH and ATP, which are needed to drive the Calvin cycle. The Calvin cycle then produces glucose. Therefore, photosynthesis provides the energy needed to produce glucose. Glucose is then used in glycolysis and cellular respiration, which yield water that is needed for photosynthesis to continue.
Draw a free energy diagram (Z-scheme) of the light reaction showing how gradients are coupled with ATP synthesis. Draw a corresponding drawing of the thylakoid membrane with the integral membrane proteins labeled
SEE CLASS OBJECTIVES
Compare photophosphorylation to oxidative phosphorylation.*
Oxidative phosphorylation is the production of ATP molecules by ATP synthase using the proton gradient established via redox reactions of an electron transport chain. Photophosphorylation is the production of ATP molecules by ATP synthase using the proton-motive force generated as light-excited electrons flow through an electron transport chain during photosynthesis. In other words, photophosphorylation is ATP production that is initially powered by energy harvested from light.
Draw an overview of the Calvin cycle. (RuBP, RUBISO, Carbon fixation, sugar production, RuBP regeneration, NADP+, NADPH).
SEE CLASS OBJECTIVES
The carbons in CO2 are oxidized. The carbons in glucose are reduced. What is the source of the electrons for the reduction of carbon during the Calvin Cycle? (This objective overlaps with the previous one...the answer should be shown in your diagram.)
Electrons from NADPH are used to reduce carbons in the Calvin cycle.
To what event does the term "fixation" occur? What is the enzyme that catalyzes fixation?*
Fixation refers to the process of combining CO2 to an organic compound. In the Calvin cycle, CO2 is fixed with RuBP to make 3PGA. The reaction is catalyzed by rubisco.
Where does the Calvin cycle take place? (Chloroplast, thylakoid, stroma, membrane)
All 3 phases of the Calvin cycle occur in the stroma of chloroplasts.
Briefly explain the relationship between aerobic respiration and photosynthesis in an ecosystem or food chain.*
Aerobic respiration, which produces most of the energy needed to perform work, depends on the presence of oxygen in cells. Oxygen is a by-product of photosynthesis. An ecosystem that has living bodies other than plants depends on the oxygen produced from photosynthesis to survive.
Agree or disagree with this statement: When you stop at the gas station, you fill-up your car with sunlight.
Agree, when you stop at the gas station, you are filling your car with sunlight. Crude oil is formed from combustible geologic deposits formed from decayed plants and animals that have been exposed to heat and pressure int he earth's crust,; the sun fed the plants that were eventually turned into oil and gasoline for the car
Understand the experiment that shows the role of the molecule 3-phosphoglycerate in glucose synthesis. (Figure 10.18)*
3PGA was shown to be the initial product of carbon reduction.
You should be able to describe approach and results of the experiment by Hershey and Chase (figure 15.2). How do the researchers identify DNA as the hereditary material?*
-They use a centrifuge. They found out DNA is not a protein, but hereditary material. They were able to identify it as hereditary material by making a DNA and a protein Radioactive.
-Hershey and Chase thought that if genes consist of DNA, then radioactive protein should be found only in the capsids outside the infected host cells, while radioactive DNA should be located inside the cells. But if genes consist of proteins, then the radioactive protein should be inside the cells with no DNA.
If given a simple drawing of a nucleotide (the monomer of the DNA molecule), label the phosphate, the deoxyribose and nitrogenous base. On the deoxyribose, label the 5' and 3' carbons.
...
What is "antiparallel" about double stranded DNA?
Double stranded DNA has multiple ends, both which are paired up.(A-T)(G-C) are also parallely matched up.
Antiparallel: Describing the opposite orientation of nucleic acid strands that are hydrogen bonded to one another, either one strand running in the 5'-->3' direction and the other in the 3'-->5' direction.
Draw a simple DNA double helix and label the sugar-phosphate backbone and the base pairs. Also, indicate what type of bond (covalent or hydrogen bond) holds the backbone or the base pairs together. Label the 5' and 3' ends of the molecule.
SEE CLASS OBJECTIVES
If given a single strand of DNA, draw the complementary strand.
5'- A C G G T A C C T T T A C G G C A - OH 3'
3' OH-T G C C A T G G A A A T G C C G T - 5'
Distinguish between "conservative" and semiconservative" replication. Understand the experiments by Meselson and Stahl (Figure 15.5) that uncovered which model for replication is accurate. What specific atom is manipulated to distinguish old from new DNA?*
-In semiconservation replication, old parental strands of DNA separate and then are used as a template for the synthesis of a new daughter strand. Each new daughter strand consists of one old strand and one new strand. In conservative replication, the bases temporarily turn outward so that the complementary strands no longer face each other and serve as a template for the synthesis of an entirely new double helix. This results in an intact parental molecule and a daughter DNA molecule consisting entirely of newly synthesized strands.
-They found that replication is semiconservative because each newly made DNA molecule comprised of one old strand and one new strand.
-Nitrogen is manipulated.
What are the "rules" DNA polymerase must follow when it synthesizes DNA (template, 3' hydroxyl (OH), primer, unidirectional)
DNA polymerase adds nucleotides in the 5'-->3' direction. This means that nucleotides are added to the 3'OH end.
Making DNA requires energy. What is the source of that energy? (Phosphate bond)*
Phosphate bonds are the source of that energy. The reaction for DNA synthesis is exergonic because the monomers that are used are deoxyribonucleoside triphosphates (dNTPs). dNTPs have 3 closely spaced phosphate groups, so their potential energy is very high.
Diagram a replication fork where DNA is being copied. Label the DNA polymerase enzymes, RNA primers, helicase, single-strand binding proteins, the leading strand, the lagging strand and the Okazaki fragments.
SEE NOTES AND WORKBOOK
Why is one strand in the replication fork replicated continuously while the other undergoes discontinuous replication? (DNA polymerase, unidirectional)
DNA can only move in one direction. The DNA Polymerase ( an enzyme) speeds up the reaction.
What is the role of the primase enzyme in replication? What is the role of topoisomerase?*
-Primase: synthesizes RNA primer
-Topoisomerase: relieves twisting forces; an enzyme that cuts DNA, allows it to unwind, and rejoins it ahead of the advancing replication fork
How are RNA primers removed from the lagging strand of the replication fork? (DNA polymerase I, DNA ligase)
DNA polymerase I attaches to the 3' end of an Okazaki fragment. As it moves along in the 5' --> 3' direction, it removes the RNA primer ahead of it. Once the RNA primer is removed and replaced by DNA, an enzyme called DNA ligase catalyzes the formation of a phosphodiester bond between the adjacent fragments.
Diagram how the circular chromosomes of prokaryotes are replicated (origin of replication, topoisomerase)
SEE BOOK
How do eukaryotic and prokaryotic chromosomes differ? How does DNA replication differ between eukaryotes and prokaryotes?
Prokaryotic chromosomes are circular and consist of only one origin of replication. Eukaryotes have linear chromosomes.
DNA polymerase III can proofread. Why is this an important function?*
The ability of DNA polymerase III to proofread decreases the chances of carcinogenic mutations.
Distinguish between a mismatch and a mutation. Which can be corrected by enzymes in the cell?
-Mismatch: can be corrected by enzymes in a cell,the bases are mismatched.
-Mutation: Change in gene responsibility, for that trait. Normally changes the phenotype.
How do proofreading and mismatch repair differ?*
-Proofreading: If a wrong base is added during DNA synthesis, the enzyme pauses, removes the mismatched dioxyribonucleotide that was just added, and then continues with synthesis.
-Mismatch repair: occurs when mismatched bases are corrected after DNA synthesis is complete.
What is the effect of UV light on DNA sequences?*
UV light affects DNA through radiation causing thymines that are side by side on the same strand to separate from their complementary base pair on the opposite strand and form a kink, connecting the two sequential thymines.
Describe the cause and symptoms of xeroderma pigmentosum (XP) (excision repair, UV light)*
-Individuals with XP are extremely sensitive to UV light. Their skin develops lesions including rough, scaly patches and, irregular dark spots after even slight exposure to sunlight.
-It is a rare autosomal recessive disease in humans.
Define each of the following terms and clearly state the relationship between the following terms: gene, protein, allele, mutation, phenotype (Concept map worksheet is helpful)
-Gene: A section of DNA (or RNA, for some viruses) that encode information for building one or more related polypeptide or functional RNA molecules along with the regulatory sequences required for its transcription.
-Protein: A macromolecule consisting of one or more polypeptide chains composed of 50 or more amino acids linked together. Each protein has a unique sequence of amino acids and generally possesses a characteristic three-dimensional shape.
-Allele: A particular version of a gene.
-Mutation: Any change in the hereditary material of an organism (DNA in most organisms, RNA in some viruses). The only source of new alleles in populations.
-Phenotype: The detectable traits of an individual.
Distinguish between identical chromosomes and homologous chromosomes (gene, allele, sister chromatids)
-Homologous Chromosomes: In a diploid organism, chromosomes that are similar in size, shape and gene content. Homologous chromosomes are produced by Meiosis (the process which creates sex cells) and 2 chromosomes in a cell (one from mom, one from dad) that have mixed codes (identical in each half of the chromosome) that have the same traits.

-Identical Chromosomes: An Identical chromosome is produced from Mitosis (cell splitting which creates an identical cell). The chromosomes are identical as the chromosome has split in half (each half carrying the same genetic code).
Distinguish between the number of chromosomes, chromatids, and homologous pairs in a cell. Consider using a human cell as your reference.
a human cell after replication has:
46 chromosomes
92 chromatids
23 homologous pairs
What determines the ploidy of an organism? How would a diploid and a triploid differ from each other? How would a diploid and an aneuploid differ?*
The number of chromosomes determines the ploidy. A diplod would be 2n while a triploid would be 3n. An aneuploid is a diploid with one more or one less chromosome.
What is the ploidy of a human somatic cell? What is the ploidy of a human gamete?
-Human somatic cell is 2n.
-Human gamete cell is n.
What are the major cellular events of Meiosis I? Of Meiosis II? (bivalent, sister chromatids, centromere, crossing over, cytokinesis)
Meiosis I is a reduction phases, where the number of chromosomes is cut in half. Meiosis II is the separation of genetically different sister chromatids.
Compare mitosis and meiosis focusing on metaphase. (In-class handout)
In meiosis, there are two phases of metaphase (I & II) which result in four haploid cells, mitosis, however, has one stage of metaphase and results in two diploid cells
Describe the ways in which meiosis and sexual reproduction produce genetic diversity. (Crossing over, segregation, fertilization)
-Crossing Over: The exchange of segments of non-sister chromatids between a pair of homologous chromosomes that occurs during meiosis 1.
-Segregation: The concept that each pair of hereditary elements ( alleles of the same gene) separate from each other during meiosis. One of Mendel's two principles of genetics.
-Fertilization: Fusion of the nuclei of two haploid gametes to form a zygote with a diploid nucleus.
When does nondisjunction take place and what are the consequences? Name some genetic conditions produced by nondisjunction.*
Nondisjunction: An error that can occur during meiosis or mitosis, in which one daughter cell receives two copies of a particular chromosome and the other daughter cell receives none.
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