Biology Final exam review

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Biology Final exam review
2011-12-09 14:39:25
Biology 1101 final review

Previous test question answers for review
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  1. Which of the following is
    true of carbon?
    • It can form polar and nonpolar
    • bonds.
  2. Consider the following
    reaction at equilibrium: CO2 + H2O ↔ H2CO3.
    What would be the effect of adding
    additional CO2 and H20?
    drive the equilibrium dynamics to the right and H2CO3 levels will increase
  3. Which of the following involves an increase in
  4. Which statement about spontaneous generation is
    • It occurs every time a new species evolves from a
    • preexisting species.
  5. Which reaction is most spontaneous?
    a reaction that is slightly exothermic and leads to a huge increase in entropy
  6. Recall the experiment on ant navigation. What parameters would have to be held constant for the test group of 75 ants in order to run a controlled experiment?
    • all variables except leg length (and therefore stride
    • length)
  7. Consider the bufferingexample discussed in class. Acetic acid (CH3COOH) and acetate (CH3COO-) form a buffer system. Which one of the buffer components would decrease in
    concentration if we were to add a strong
    acid to the solution containing the
  8. Which of the following linkages would you expect to find at a branch point in glycogen or amylopectin?
    α-1,6-glycosidic linkage
  9. In what important way does a
    competitive inhibitor differ from an allosteric inhibitor?
    • A competitive inhibitor binds to the active site,
    • whereas an allosteric inhibitor binds to a site other than the active site.
  10. Recall Pasteur's experiment on spontaneous generation. If he had just warmed the nutrient-rich broth, rather than boiled it, what would have been the likely outcome of his
    • Cells would have appeared in
    • both flasks.
  11. If an atom has a charge of +2, which of the following must be true?
    It has two more protons than electrons.
  12. An atom has five electrons in its valence shell.
    How many single covalent bonds would you expect it to form in most circumstances?
  13. What holds electrons in a covalent bond?
    • The negative charges on the electrons are attracted by
    • the positive charges on both nuclei.
  14. Why are polymerization
    reactions endergonic?
    They reduce entropy.
  15. You isolate a molecule and
    determine it is nonpolar. Based on this
    property, the molecule is largely composed of the elements _____.
    carbon and hydrogen
  16. How do the α and β forms of
    glucose differ?
    Their ring structures differ in the location of a hydroxyl group.
  17. Consider the buffering
    example discussed in class. Acetic acid (CH3COOH) and acetate (CH3COO-
    ) form a buffer system. Which one of the buffer components would increase in
    concentration if we were to add a strong
    base to the solution containing the
  18. Nitrogen (N) normally forms only three covalent bonds because it has a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). Make a sketch of this molecule. Count the number of electrons in your sketch. Compare this number to the number of valence electrons in one N and four H's. What do you predict to be the charge on this molecule?
  19. A restriction enzyme cuts which particular molecule we discussed in class?
  20. Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose. Why is this logical?
    • The geometry of the bonds is different, and the shapes
    • of enzyme active sites are highly specific.
  21. You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?
    primary structure
  22. Nucleic acids have a definite polarity, or directionality. Stated another way, one end of the molecule is different from the other end. How are these ends described?
    • One end has an unlinked 3’ carbon; the other end has
    • an unlinked 5’ carbon.
  23. Why do chemical reactions tend to speed up when heat is applied to the reaction mixture?
    • A)The reactants move faster.
    • B) The reactants collide more
    • often.
    • C) The reactants have greater energy.
  24. If you were going to develop a new antibiotic
    against bacteria, you would probably need to become an expert on which of these carbohydrates?
  25. The lock-and-key analogy for enzymes applies to
    the _____.
    specificity of enzymes binding to their substrate
  26. On the tree of life, the branch leading to animals is closer to fungi than it is to the branch leading to land plants. Which of the following statements is correct?
    • Animals and fungi are more closely related to each
    • other than animals are to land plants
  27. An enzyme has a total of four active sites. When you denature the molecule and
    study its composition, you find that
    each active site occurs on a different polypeptide. Which of the following
    hypotheses does this observation support?
    The protein has quaternary structure.
  28. What type of interaction is directly responsible for the formation of protein secondary structure?
    • Hydrogen bonds between sections
    • of the polypeptide backbone
  29. Which of the following best describes DNA's
    secondary structure?
    double antiparallel helical strands
  30. If the primary structure of a protein is
    • any higher level folding of the protein will be
    • incorrect.
  31. You have isolated a previously unstudied protein, identified its complete structure in detail, and determined that it catalyzes the breakdown of a large substrate. You notice it has two binding sites. One of these is large,
    apparently the bonding site for the large substrate; the other is small, possibly a binding site for a regulatory molecule. What do these findings tell you about the mechanism of this protein?
    • It is probably an enzyme that works through allosteric
    • regulation.
  32. What feature of mononucleotides provides the
    energy needed for polymerization when nucleic acids are formed?
    their phosphate groups
  33. Enzyme-catalyzed reactions increase in rate very rapidly at low substrate concentrations but plateau at higher substrate concentrations Why?
    • At high substrate concentrations, the enzyme molecules
    • present are working at maximal speed and are unable to further increase the rate of reaction.
  34. Complementary base pairing explained Chargaff's findings—the fact that the number of cytosines in a DNA sample equals the number of guanines, and the number of thymines equals the number of adenines. Complementary base pairing is the formation of hydrogen bonds between antiparallel strands of the DNA molecule. Which statement
    regarding complementary base pairing is correct?
    • In DNA, the purine base adenine (A) always pairs with
    • the pyrimidine base thymine (T)
  35. What forms the "backbone" of a nucleic
    • a chain of sugar and phosphate groups, linked through
    • phosphodiester bonds
  36. The type of bond that forms
    between a 3’-OH (hydroxyl) group of one nucleic acid and the 5’-P (phosphate)
    group of another nucleic acid is called a _________________ bond.
  37. What is gel electrophoresis used for?
    • B)to separate macromolecules such as DNA by size
    • D) to separate macromolecules such as DNA by charge
  38. Dairy cattle were unknown in Thai culture until recently, and 97% percent of Thai people are lactose intolerant as adults. Which explanation for such widespread lactose intolerance is most likely correct?
    Evolutionarily, producing an enzyme to break down a sugar that will never be encountered is wasteful.
  39. A glycosidic linkage is analogous to which of
    the following in proteins?
    a peptide bond
  40. Environments all over the world are changing as
    a result of global warming. Could this influence natural selection?
    Yes. Traits that help individuals produce more offspring in warmer environments will increase in frequency.
  41. When nucleotides polymerize to form a nucleic
    acid _____.
    • a covalent bond forms between the sugar of one
    • nucleotide and the phosphate of a second
  42. What does it mean to say that
    a molecule has an optical isomer?
    • It has two mirror-image forms, which cannot be exactly
    • superimposed on each other.
  43. Sickle-cell anemia results when valine replaces glutamate at position 6 of the β-globin subunit of hemoglobin. The sickling seen in red blood cells with the defective hemoglobin
    subunit affects the _____.
    primary structure of hemoglobin
  44. Agrobacterium is a type of bacteria that infects plants and causes them to form tumors. You are asked to determine how long a plant
    must be exposed to the bacteria to become infected. Which of the following experiments will provide the best data for that question?
    • determining the number of tumors formed on a plant
    • depending on how long it is exposed to Agrobacterium
  45. Forensic science uses genetic fingerprinting
    techniques to identify individuals who may or may not have been present at crime scenes. These techniques identify unique patterns present in the DNA of each individual. What are these unique patterns based upon?
    • a) variable tandem nucleotide
    • repeats present in the individual’s DNA
    • c) restriction digestion of a person’s genetic material
  46. Several of the molecules called vitamins act as
    enzyme cofactors. Vitamin deficiencies cause disease. What is the most direct
    explanation for this?
    • If cofactors are missing, enzymes cannot function properly, and important reaction products will be
    • absent from cells.
  47. How does primary protein structure affect the
    function of protein enzymes?
    • Substrates interact with R-groups at the enzyme's
    • active site.
  48. Both starch and cellulose are glucose polymers.
    Why can animals easily degrade starch, but not cellulose?
    • Animals have the enzymes to degrade a-1,4-glycosidic
    • bonds, but not b-1,4-glycosidic bonds..
  49. The concept of ______________________ explains why antibiotics like penicillin and antimicrobial substances like lysozyme kill
    or inhibit the growth of bacteria without a similar effect upon the infected host.
    selective toxicity
  50. Which of the following linkages would you expect to find at a branch point in glycogen or amylopectin? (Hint: the hydroxyl group of the sugar monomers in this polysaccharide are
    located below the “plane” of carbon #1)
    α-1,6-glycosidic linkage
  51. Consider the following reaction at equilibrium:
    CO2 + H2O ↔ H2CO3. What would be
    the effect of adding additional H2CO3?
    • drive the equilibrium dynamics to the left and H2CO3
    • levels will decrease
  52. You've been asked to analyze
    a reaction that took place at 300 K. ∆H was -150 and ∆S was +0.4. Is the
    reaction endothermic or exothermic?
  53. Cooking oil and gasoline (a hydrocarbon) are not amphipathic molecules. Why?
    They do not have a polar or charged region.
  54. Suppose that the plasma membrane around a flagellum is opened to reveal the axoneme
    inside. The dynein sidearms between the peripheral microtubule doublets are
    then removed by chemical treatment. ATP is then added. What is the expected
    There will be no movement, because the ability to use ATP is lost
  55. In an experiment involving planar bilayers, a solution of table salt (sodium and chloride ions in water) is added on the left side of the membrane while pure water is added on the right side. After 30 minutes the researchers test for the presence of ions on each side of the membrane. The right side tests negative
    for ions. What can you conclude?
    Ions cannot cross planar bilayers.
  56. Which of the following phospholipid
    membranes would be most permeable to glycerol?
    one with short and unsaturated tails
  57. Region A has a low solute concentration. Region B has a high solute concentration.
    They are separated by a selectively permeable membrane. The movement of water from region A to region B occurs by the process of _____.
  58. Under what circumstances does membrane transport always require energy?
    whenever a solute needs to be moved from low concentration to high concentration through a phospholipid bilayer membrane
  59. In the nucleoplasmin experiment discussed in
    class, protease treatment was used to separate the protein into “core” and “tail” regions. After radiolabeling of the core and tail fragments, it was observed that core fragments remained in the cytoplasm. Why?
    core fragments lacked a nuclear localization signal
  60. All cells, regardless of whether they are
    prokaryotic or eukaryotic, contain which three structures?
    chromosome, ribosomes, plasma membrane
  61. According to the signal hypothesis, as the
    ribosome begins to translate a new protein, the first couple of amino acids
    translated by the ribosome will end up being bound by the _______________.
    signal recognition particle
  62. Hormones are chemical substances produced in one organ that are released into the
    bloodstream and affect the function of a target organ. For the target organ to respond to a particular hormone, it must ________.
    have receptors that recognize and bind the hormone molecule.
  63. Assuming ATP levels in the cell are
    high, if fructose 6-phosphate is present in high concentrations in the glycolytic cycle, what is the likely end outcome of the pathway?
    a subsequent increase in glucose 6-phosphate concentration will occur, followed by an increase in glycogen concentration.
  64. Proteins are amphipathic molecules that contain nonpolar (hydrophobic) amino acids and polar (hydrophilic) amino acids. Where would you expect to find the hydrophobic
    and hydrophilic amino acid residues of a protein that spans a cell membrane?
    • The hydrophobic amino acids would be oriented toward the outside of the protein and come into contact with the hydrocarbon tails of the phospholipid bilayer, whereas the hydrophilic proteins would be more concentrated in the
    • protein interior.
  65. The fact that a single signal-receptor
    complex results in the activation of several second messenger molecules enables
    the cell signal to be ________.
  66. To what does the 9 + 2 arrangement of microtubules, typical of cilia and eukaryotic flagella, refer
    the arrangement of microtubules within the axoneme
  67. The process of joining the hydrolysis of ATP generating ADP + Pi to an endergonic reaction to provide the necessary energy to drive the energy requiring reaction to the formation of products is known as:
    energetic coupling
  68. Spherocytosis is a defect associated
    with a defective cytoskeletal protein in red blood cells. What do you suspect
    is one consequence of defective cytoskeletal proteins in red blood cells?
    abnormal cell shape
  69. In the pulse-chase experiment discussed
    in class, researchers applied a short pulse of radioactively labeled leucine, followed by a long chase of unlabeled leucine, to cells that secrete digestive enzymes. The bulk of the radioactive label was initially found in the rough ER, then in the Golgi apparatus, followed by secretory vesicles that emptied into a duct outside the cell. These results BEST support which of the following hypotheses?
    Proteins that are destined to be secreted outside the cell follow a specific pathway that culminates with secretory vesicle fusion with the plasma membrane releasing the protein into the extracellular space.
  70. When you are startled, and have an autonomic response preparing you to flee from danger, which of the following is released into your bloodstream that leads to a variety of different effects in a variety of different tissues? (Hint: What causes the “fight or flight” response?)
  71. A metabolic pathway, glycolysis, is active when cellular energy levels are
    ________; the regulatory enzyme, phosphofructokinase (PFK-1), is ________ by
    high levels of ATP.
    low; inhibited
  72. What will happen to a red blood cell (rbc),
    which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of 9.0% salt water? (Hint think about cytoplasm concentration relative to outside)
    • The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the
    • rbc.
  73. Margulis's theory of endosymbiosis proposes that
    ____________ evolved from
    mitochondria; bacteria
  74. The hydrolytic enzymes (hydrolyases) present in the lysosome only become active upon phagosome-lysosome fusion. What is the signal that leads to their activation?
    • an increase in pH mediated by
    • H+ flux through membrane vacuolar ATPases on the lysosome
  75. Intercalated disks are cell-cell junctions found between cardiac muscle cells. A feature of
    intercalated disks is a large number of gap junctions. This means ________.
    water and small ions can readily pass from one cardiac muscle cell to the next, “sharing nutrients”.
  76. What is the most likely role of a cell
    that contains an extensive smooth ER?
    It synthesizes large quantities of lipids
  77. Steroid hormones bind to receptors inside the cell and alter their conformation. The
    hormone-receptor complex is then transported into the nucleus, where it can directly affect gene expression. To get from the location where the receptor binds the hormone to its site of action, the receptor-hormone complex must ________.
    be transported through the nuclear pore complex.
  78. Acetylcholine is a neurotransmitter that binds to receptors on skeletal muscle cells. This
    binding brings about a series of events that result in contraction of skeletal muscle. Venom from black widow spiders causes an explosive release of acetylcholine. What would that do to its victims?
    Muscles would be unable to relax.
  79. What do myosin, dynein, and kinesin all
    have in common?
    They all hydrolyze ATP to provide energy for movement i.e they are all motor proteins.
  80. Sodium-potassium pumps:
    move two potassium ions and three sodium ions while consuming an ATP for each cycle
  81. Gluconeogenesis is the anabolic process that converts pyruvate back into glucose. The key
    regulatory enzyme in this pathway is fructose 1, 6 – bisphosphotase. Gluconeogenesis is active when ATP levels are _____________ and the above enzyme’s active site _____________ when bound by ATP at its second or allosteric ATP binding site
    high; “opens”
  82. If one molecule of glucose is taken through the entire glycolysis pathway, and
    ONLY the glycolysis pathway, what are the NET products that store the remaining chemical free energy?
    2 ATPs, 2 NADHs, and 2 pyruvates
  83. Which of the following cell types is
    likely to contain tight junctions?
    cells lining the stomach that prevent nutrients from leaking out
  84. The formation of a cleavage furrow in animal cells results from interactions between actin and myosin proteins. This process occurs at the end of mitosis and is referred to as _________________.
  85. What will happen to a red blood cell (rbc),
    which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water? (Hint think about cytoplasm concentration relative to outside (pure water, no ion concentration)
    The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the rbc.
  86. You have a distant cousin, age 4, who is always tired and fatigued and is not able to play games and sports like other healthy
    children. He most likely has an enzyme deficiency or defect associated with
    which intracellular organelle?
  87. What is the correct order for the four steps in signal transduction?
    reception, processing, response, deactivation
  88. What type of enzyme could effectively “turn off” a phosphorylation cascade response
    at the level of enzyme activity?
    a phosphotase
  89. Predict what would happen if a mutant Ras protein was unable to exchange GTP for GDP.
    (i.e. the protein is stuck with bound GTP)
    The pathway would be “locked” in an activated state and proteins downstream from Ras would be hyperphosphorylated (overphosphorylated)
  90. Predict what would happen if a mutant Ras protein was unable to exchange GDP for GTP.
    (i.e. the protein is stuck with bound GDP)
    The proteins downstream from Ras would not become phosphorylated and not become active.
  91. Simple diffusion is most accurately described by which of the following?
    Solutes must be soluble (able to pass through) in the cell membrane, and a concentration gradient must be present in order for any net diffusion to take place.
  92. Why might adding inorganic phosphate to a reaction mixture where glycolysis was
    rapidly proceeding help sustain the metabolic pathway?
    The metabolic intermediates of glycolysis are phosphorylated.
  93. Which of the following is an example of signal deactivation?
    GTP bound to Ras becomes hydrolyzed to GDP.
  94. Lysosomal fusion and degradation of damaged organelles is a process called
  95. A protein lacking a signal sequence directing it to a particular location in a cell will likely reside _____.
    in the cytoplasm
  96. What causes turgor pressure in plant cells?
    osmosis of water into the plant cell due to the higher concentration of solutes inside the cell
  97. Which of the following statements about signal receptors is true?
    Receptors change conformation upon signal binding.
  98. Which of the following statements regarding
    G-proteins is true?
    They are inactivated when they are bound to GDP.
  99. If a motile bacteria encounters a high concentration of attractant, it will……..
    increase its ratio of runs::tumbles
  100. Which of the following events takes place in the
    electron transport chain?
    the extraction of energy from high-energy electrons remaining from glycolysis and the Krebs cycle
  101. Marfan syndrome results from a defect in a
    single gene FBN1. Individuals with
    Marfan syndrome exhibit a wide array of phenotypic effects such as increased height, disproportionately long limbs and fingers, an abnormally shaped chest
    and potentially severe heart problems. The FBN1
    gene influences many traits and is therefore ___________.
  102. A cross between pure-breeding chicken lines with
    rose combs and pea combs produces offspring all having a new phenotype, walnut comb. If two walnut comb chickens are mated, the offspring will have the following phenotypes: walnut comb, rose comb, pea comb, and a new phenotype called single comb. Which of the following statements best explains this result?
    The alleles of two genes are interacting to produce the different phenotypes.
  103. Cells that utilize ________ as the terminal
    electron acceptor in the electron transport chain are said to undergo _________ respiration.
    oxygen; aerobic
  104. In ________ fat mitochondria; the energy from the proton motive force generated from the electron transport chain is released as heat instead of utilization in ATP production.
  105. During meiosis, Sister chromatids separate
    during ________.
    anaphase II
  106. What is a major difference between meiosis II and mitosis?
    Meiosis II takes place in a haploid cell, while mitosis takes place in diploid cells.
  107. If a plant cell wanted to augment its ATP production, what type of energy production pathway would it choose?
    cyclic photophosphorylation
  108. Why is it critical for plants to maintain a high
    concentration of carbon dioxide in the leaves?
    It helps prevent photorespiration
  109. Joseph Priestly was the first person to demonstrate that oxygen consumed in respiration is released by plants. He did this using what two organisms?
    a house plant and a mouse
  110. Which of the following compounds inhibits pyruvate dehydrogenase via feedback inhibition? (Hint:
    think about high and low energy levels and what is present with each)
  111. What is a major difference between mitosis and
    meiosis I?
    Sister chromatids separate in mitosis, and homologues separate in meiosis I.
  112. The chemiosmotic hypothesis is an important key
    to understanding general metabolism because ________.
    it explains how ATP is synthesized by a proton motive force.
  113. The Calvin cycle uses six ATP molecules to
    produce one 3-carbon sugar (glyceraldehyde-3-phosphate, 3GP) from three molecules of RuBP and three molecules of carbon dioxide. Yet the Calvin cycle actually requires nine ATP molecules to function. Why? (HINT: It’s a cycle!)
    Three additional ATP molecules are used to regenerate RuBP.
  114. The electrons of photosystem II are excited and
    transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?
  115. If a cell has accumulated DNA damage during S
    phase, it is unlikely to ________. (Hint: think about the steps in interphase)
    • pass the G2
    • checkpoint.
  116. In 1985 Hassold and Chiu found that the
    likelihood of miscarriage increased with maternal age. What is the most likely explanation for the relationship between age and miscarriage?
    Ova are arrested in meiosis until ovulation. As a result, completion of meiosis in the older woman is more likely to result in aneuploidy or other chromosomal abnormalities.
  117. For cells to divide more rapidly, increased production would likely be required of each of the following proteins except ________. (Hint: Which one is a tumorsuppressor?)
  118. Centromeres split and sister chromosomes migrate to opposite poles in _____.
    anaphase II
  119. Photorespiration is ________.
    • a process involving addition of oxygen to
    • ribulose-1,5-bisphosphate and the formation of formation of the products 3-phosphoglycerate and 2-phosphoglycolate, decreasing sugar intermediates from the Calvin cycle
  120. The sequestering of carbon dioxide in CAM plants helps them to survive by:
    allowing CO2 to be gathered at one particular time for use at another time.
  121. What is the end result of meiosis and subsequent
    fertilization of gametes
    an offspring with a chromosome complement unlike that of either parent
  122. What is the best evidence for the presence of two photosystems?
    The combination of far red and red light is much more effective at stimulating photosynthesis than either color alone; i.e. the enhancement effect.
  123. The biochemical outcome of the activity of
    photosystem I is to:
    reduce NADP+
  124. A certain species of animal has six pairs of chromosomes. How many individual chromosomes do the nuclei of these animal’s somatic cells have during G2 phase?
  125. Mitotic spindle fibers are composed of what
    cellular structures?
  126. Taxol is a drug that stabilizes microtubules in
    animal cells and prevents them from depolymerizing. Consequently cells treated Taxol fail to complete mitosis. What event during the subphases of mitosis
    is most likely to be inhibited by this drug?
    movement of the sister chromatids to their respective poles
  127. Which of the following statements concerning crossing over is true?
    Chromosomes that result from crossing over have a mixture of maternal and paternal alleles
  128. The consequence of E2F activation is that:
    cells would immediately enter the S phase
  129. As electrons are passed through the system of
    electron carriers associated with photosystem II, they lose energy. What happens to this energy?
    It is used to establish and maintain a proton gradient.
  130. Which of the following statements most accurately compares photosynthesis and
    Photosynthesis stores energy in complex organic molecules; respiration releases the energy stored in complex organic molecules.
  131. Under which conditions will the
    Krebs cycle be activated?
    high levels of AMP and ADP
  132. How does carbon fixation differ between C3
    and C4 plants?
  133. Rubisco is the primary enzyme that catalyzes carbon fixation in C3 plants, and phosphoenolpyruvate carboxylase can catalyze carbon fixation in C4 plants.
  134. A cross between Ttrr and TtRR snapdragon plants
    where T is the dominant allele for plant height (tall), t is the recessive allele for plant height (dwarf), R is the dominant allele for flower color (red), and r is the recessive allele for flower color (white) would result in what proportion of offspring with pink flowers on dwarf plants?
  135. The Z scheme models the interaction between photosystem I and photosystem II. What does the “Z” represent?
    the changes that occur in potential energy of electrons as they move through the two photosystems.
  136. The first gap in the cell cycle (G1) corresponds to ________.
    normal growth and functioning
  137. A man who carries an allele of an X-linked gene will pass it on to ________.
    all of his daughters.
  138. Metaphase occurs prior to the splitting of centromeres. It is characterized by ________.
    aligning of chromosomes on the equator.
  139. If an individual with type O blood mates with an individual with type AB blood, what are the possible blood types (phenotypes) of their offspring?
    A and B
  140. Nerve cells lose their ability to undergo mitosis. Instead, they are permanently stuck in ________.
  141. If a heterozygous type A (blood type) man has a
    child with a heterozygous type B woman, what are the possible blood types of the offspring, regardless of whether the child is male or female?
    AB, A, B, and O
  142. A
    recessive allele on the X chromosome is responsible for red-green color
    blindness in humans. A woman with normal vision whose father is color blind
    marries a color-blind male. What is the probability that this couple's first
    son will be color blind?
  143. Once researchers understood that chromosomes are moved by the spindle microtubules, the next question they wanted to answer is how the microtubules function to bring about this process. They used fluorescent labels to make the chromosomes and the microtubular structures fluoresce. When anaphase began (centromeres split), they photobleached a section of microtubules. As chromosomes moved
    toward the poles of the daughter cells, the photobleached sections of the microtubules remained stationary. This result suggests that ________.
    the microtubules elongate and shorten at their kinetochore (the "crown" apparatus attached to each sister chromatid) end.
  144. Once a cell completes mitosis, molecular division triggers must be turned off. What happens to MPF during mitosis?
    Cyclin is degraded; the concentration of cyclin-dependent kinase remains unchanged, but without cyclin, MPF is not formed.
  145. Which early theory, proposed by Charles Darwin,
    involved the shedding of gemmules by somatic cells and the subsequent traveling of these gemmules through the bloodstream to the reproductive tissue to provide genetic info to gametes?
  146. American Idol called and your audition was a
    success. You quickly run up four flights of stairs to schedule a make-up quiz with your professor, and feel an odd burning sensation in your legs, which you haven’t felt since you became addicted to text messaging during Bio1100. The eventual soreness that you feel in your legs results from a buildup of ________ _______, and this buildup is a result of your muscle cells undergoing a metabolic reaction called _____________.
    lactic acid; fermentation
  147. The M-phase checkpoint is designed to make sure
    all chromosomes are attached to the mitotic spindle. If this fails to happen, in which stage of mitosis would the cells be most likely to arrest?
  148. Nondisjuction of chromosomes results in
  149. A proton ionophore, a molecule that forms an
    artificial channel allowing hydrogen ions to cross membranes, will _____ the concentration of ATP in a cell. HINT: Consider what would happen if the
    concentrations of hydrogen ions on both sides of the inner mitochondrial membrane were equal.
  150. What is a key difference between benign tumors
    and metastatic tumors?
    metastatic tumors are invasive.
  151. One of the causes of cancer is the mutation of
    genes that encode proteins in the biochemical pathway regulated by PDGF, a growth factor. How could such mutations cause cancer?
    Cancer could result if the mutations caused the biochemical pathway to become permanently active.
  152. Suppose two AaBbCcDd individuals are mated. Assuming that the genes are not linked, what fraction of
    the offspring are expected to be homozygous recessive for the four traits?
  153. What is the frequency of each phenotype in the F2 generation of a cross between two homozygous parent
    peas with the genotypes RR and rr? (Remember the difference between phenotype and genotype.)
    three round, one wrinkled
  154. Given that 2.5 ATP are produced per NADH molecule and 1.5 ATP are produced per FADH2
    molecule, how much ATP would result from the B – oxidation of a 12 carbon fatty acid, if 2 ATP are required to activate the process?