Exam 2 PQs

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Mod 2 Class 1 Practice Questions What does consanguineous marriage do to diversity? Why is this the case? I. Promotes diversity II. Prevents diversity III. Has no effect on diversity IV. Shifts the equilibrium of new and old mutants Which functions promote genetic diversity? I. Homologous Recombination II. Deleterious Loss-of-Function Mutations III. Lethal Gain-of-Function Mutations IV. Independent Assortment a. I,II,IV b. II,III c. IV d. I,IV e. II,III,IV f. None of the above Which statement is FALSE? I. Somatic cells under-go mitosis to form the body II. Somatic cells produce genetically identical daughter cells III. Germ-line cells under-go mitosis to form gametes IV. Germ-line cells produce genetically unique daughter cells V. Somatic cells and Germ-line cells are required for sexual reproduction Which statement is TRUE? I. Sister chromatids separate by cohesion degradation in meiosis I II. Bivalents form after homologous recombination during meiosis I III. Tension from the kinetochore is balanced out by the chiasmata IV. Axial cores maintain chromosome structure on the metaphase plate V. None of the above Which statement is FALSE?

I. The Law of Independent Assortment states that alleles can segregate independently of one another II. Wild-Type phenotypes are indicative of dominant alleles III. Mutations can cause proteins to either lose or gain new functions. IV. You can be phenotypically wild-type, while genotypically mutant. V. None of the above When genotyping your family, you notice that your siblings have haplotype blocks different from your parents but like you. What is the most likely cause? I. Recombination events upon gamete formation generated a new chunk of polymorphisms II. Your mother is not your biological mother III. Your father is not your biological father IV. Your parents are not your biological parents V. Recessive mutations from both parents occur in the same genes After feeding your mice mutagenic food for 3 weeks, you notice their offspring are all phenotypically normal. In the footsteps of Mendel, you breed the offspring amongst each other and find that some of the mice are now sterile and will no longer reproduce. What type of pattern is this most likely to be? I. Homozygous, monogenic, recessive mutation II. Homozygous, monogenic, dominant mutation III. Heterozygous, monogenic, dominant mutation IV. Heterozygous, monogenic, recessive mutation V. A multigenic disease Ch 16 Practice Questions 1. Which of the following statements is TRUE? a. Because endocrine signals are broadcast throughout the body, all cells will respond to the hormonal signal. b. The regulation of inflammatory responses at the site of an infection is an example of paracrine signaling. c. Paracrine signaling involves the secretion of signals into the bloodstream for distribution throughout the organism. d. The axons of neurons typically signal target cells using membrane-bound signaling molecules that act on receptors in the target cells. 2. Which of the following statements is TRUE? a. Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell to change its behavior. b. To function, all extracellular signal molecules must be transported by their receptor across the plasma membrane into the cytosol. c. A cell-surface receptor capable of binding only one type of signal molecule can mediate only one kind of cell response. d. Any foreign substance that binds to a receptor for a normal signal molecule will always induce the same response that is produced by that signal molecule on the same cell type.

3. The following happens when a G-protein-coupled receptor activates a G protein. a. The β subunit exchanges its bound GDP for GTP. b. The GDP bound to the α subunit is phosphorylated to form bound GTP. c. The α subunit exchanges its bound GDP for GTP. d. It activates the α subunit and inactivates the βγ complex. 4. You are interested in cell-size regulation and discover that signaling through a GPCR called ERC1 is important in controlling cell size in embryonic rat cells. The G protein downstream of ERC1 activates adenylyl cyclase, which ultimately leads to the activation of PKA. You discover that cells that lack ERC1 are 15% smaller than normal cells, while cells that express a mutant, constitutively activated version of PKA are 15% larger than normal cells. Given these results, which of the following treatments to embryonic rat cells should lead to smaller cells? a. addition of a drug that causes cyclic AMP phosphodiesterase to be hyperactive b. addition of a drug that prevents GTP hydrolysis by Gα c. addition of a drug that activates adenylyl cyclase d. addition of a drug that mimics the ligand of ERC1 5. The local mediator nitric oxide stimulates the intracellular enzyme guanylyl cyclase by a. activating a G protein. b. activating a receptor tyrosine kinase. c. diffusing into cells and stimulating the cyclase directly. d. activating an intracellular protein kinase. 6. The growth factor Superchick stimulates the proliferation of cultured chicken cells. The receptor that binds Superchick is a receptor tyrosine kinase (RTK), and many chicken tumor cell lines have mutations in the gene that encodes this receptor. Which of the following types of mutation would be expected to promote uncontrolled cell proliferation? a. a mutation that prevents dimerization of the receptor b. a mutation that destroys the kinase activity of the receptor c. a mutation that inactivates the protein tyrosine phosphatase that normally removes the phosphates from tyrosines on the activated receptor d. a mutation that prevents the binding of the normal extracellular signal to the receptor 7. A protein kinase can act as an integrating device in signaling if it a. phosphorylates more than one substrate. b. catalyzes its own phosphorylation. c. is activated by two or more proteins in different signaling pathways. d. initiates a phosphorylation cascade involving two or more protein kinases. 8. Which of the following statements is TRUE? a. MAP kinase is important for phosphorylating MAP kinase kinase. b. PI 3-kinase phosphorylates a lipid in the plasma membrane. c. Ras becomes activated when an RTK phosphorylates its bound GDP to create GTP. d. Dimerization of GPCRs leads to Gα activation. 9. When Ras is activated, cells will divide. A dominant-negative form of Ras clings too tightly to GDP. You introduce a dominant-negative form of Ras into cells that also have a

normal version of Ras. Which of the following statements is TRUE? a. The cells you create will divide less frequently than normal cells in response to the extracellular signals that typically activate Ras. b. The cells you create will run out of the GTP necessary to activate Ras. c. The cells you create will divide more frequently compared to normal cells in response to the extracellular signals that typically activate Ras. d. The normal Ras in the cells you create will not be able to bind GDP because the dominant-negative Ras binds to GDP too tightly. 10. The lab you work in has discovered a previously unidentified extracellular signal molecule called QGF, a 75,000 -dalton protein. You add purified QGF to different types of cells to determine its effect on these cells. When you add QGF to heart muscle cells, you observe an increase in cell contraction. When you add it to fibroblasts, they undergo cell division. When you add it to nerve cells, they die. When you add it to glial cells, you do not see any effect on cell division or survival. Given these observations, which of the following statements is most likely to be TRUE? a. Because it acts on so many diverse cell types, QGF probably diffuses across the plasma membrane into the cytoplasm of these cells. b. Glial cells do not have a receptor for QGF. c. QGF activates different intracellular signaling pathways in heart muscle cells, fibroblasts, and nerve cells to produce the different responses observed. d. Heart muscle cells, fibroblasts, and nerve cells must all have the same receptor for QGF Ch 18 Practice Questions 1. Which of the following events does NOT usually occur during interphase? a. Cells grow in size. b. The nuclear envelope breaks down. c. DNA is replicated. d. The centrosomes are duplicated. 2. In which phase of the cell cycle do cells check to determine whether the DNA is fully and correctly replicated? a. at the transition between G1 and S b. when cells enter G0 c. during M d. at the end of G2 FEEDBACK: Cells will check whether the DNA is fully and correctly replicated at the end of G. It does not make sense to monitor DNA replication before S phase because DNA replication has not yet occurred. When cells enter G0, they do not replicate their DNA. During M phase, chromosomes are condensed for chromosome segregation, so it would be difficult for the cell to examine the replicated DNA for errors at that point. 3. Which of the following statements about the cell cycle is FALSE? a. Once a cell decides to enter the cell cycle, the time from start to finish is the same in all eukaryotic cells. b. An unfavorable environment can cause cells to arrest in G1.

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