Cell Exam 3 - Cellular and Molecular Biology Exam 3 PDF

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Cellular and Molecular Biology Exam 3...

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Cell Exam 3 1. Which one of the following statements about CAM plants is correct? A. accumulate malate in the vacuoles of their cells, which is eventually used to drive Calvin cycle reactions B. are a type of C3 plants C. open their stomata during the day and close them at night D. separate the functions of carbon fixation and the Calvin cycle into different types of cells E. none of the above statements are correct 2. ________________ bind to receptors inside cells A. steroid hormones B. neurotransmitters C. auxins D. all of the above E. both a and c 3. Which of the following statements about the protein calmodulin is TRUE? A. it interacts directly with the ligand receptor B. it interacts directly with the G protein C. it binds to Ca2+ ions to mediate a cellular response D. It binds to the Ca2+ ion channel causing it to close E. it induces ATP hydrolysis 4. Each of the following about G proteins is true EXCEPT A. they are seven-pass transmembrane proteins B. The alpha subunit typically activates an intermediate protein C. The three subunits dissociate into alpha GTP and beta/gamma dimer D. associated G proteins become activated by binding to GTP E. Activated G protein diffuses away from the receptor 5. The addition of an oxygen molecule to ribulose bisphosphate (RuBP) is most accurately referred to as: A. oxidative phosphorylation B. photorespiration C. photophosphorylation D. aerobic respiration E. phosphorespiration 6. Each molecule of CO2 produced by C4 cycle uses ____ ATP molecules A. 12 B. 2 C. 18 D. 1 7. Less condensed regions of DNA are called _______________ and typically have a diameter of approximately ____________ A. euchromatin; 700 nm arranged in the form of radial loops B. euchromatin; 30 nm arranged in the form of radial loops C. heterochromatin; 300 nm arranged in the form of radial loops

D. heterochromatin; 30 nm arranged in the form of radial loops 8. Which pair are examples of second messengers? A. sodium, potassium ions B. amino acids, proteins C. steroids, lipids D. sugars, starches E. cAMP, calcium ions 9. What type of receptor does IP3 bind to ? A. G-protein coupled B. ligand-gated Ca 2+ channel C. enzyme-linked D. sensor kinase 10. In the heart, epinephrine increases the heart rate. The mechanism involes: A. Epinephrin → adenylyl cyclase → PKA activation → cAMP → troponin and phospholamban phosphorylation B. Epinephrin → PKA activation → adenylyl cyclase → cAMP → troponin and phospholamban phosphorylation C. Epinephrin → adenylyl cyclase → cAMP → PKA activation → troponin and phospholamban phosphorylation D. Epinephrin → adenylyl cyclase → cAMP → PKA activation → troponin inactivation/phospholamban phosphorylation 11. A hormone binds to a receptor and activates the cAMP signal transduction pathway ultimately leading to the cell response. Which of the following is NOT a likely mechanism for reversing (or shutting off) cAMP transduction? A. the hormone dissociating from the receptor B. the GTP on the alpha subunit of the G protein is hydrolyzed to GDP C. Activate phosphodiesterase D. Activate adenylyl cyclase E. Protein phosphatases remove phosphates from proteins initially activated by protein kinase A 12. Phospholipase C hydrolyzes a membrane phospholipid to produce A. IP3 only B. protein kinase C only C. diacylglycerol only D. both IP3 and protein kinase C E. both IP3 and diacylglycerol 13. What structure cements plant cells together? A. middle lamella B. hemidesmosomes C. plasmodesmata D. primary cell walls E. adherens junctions

14. Which of the following statements about the cell wall is FALSE? A. The cell wall constitutes the ECM of plants B. the cell wall is composed predominantly of proteins C. the cell wall provides protection, rigidity, and shape to plant cells D. the cell wall is composed of two distinct layers E. the cell wall is composed mainly of carbohydrates 15. Teams of researchers working at a pesticide company are trying to produce a new rodent poison that will cause junctions between intestine cells to leak. This poison will be used on rat infestations at an old waterfront warehouse. The researchers are developing a poison that will be incorporated into grain and left where the rodents will feed on it. The poison is supposed to work by A. breaking down the gap junctions between the gut epithelial cells B. breaking down the tight junctions between the gut epithelial cells C. breaking down the anchoring junctions between the gut epithelial cells D. breaking down the communicating junctions between the gut epithelial cells E. breaking down the nuclear membranes of the gut epithelial cells causing the rupturing of the nucleus and thus preventing new cell growth and protein synthesis. 16. Which enzyme is directly responsible for breaking down cAMP to inactive AMP? A. protein kinase A B. protein kinase C C. adenylyl cyclase D. phosphodiesterase E. protein phosphatase 17. Which ECM molecule provides structure while allowing certain tissues to expand and contract (e.g. lungs during breathing, intestine during digestion)? A. collagen B. elastin C. fibronectin D. laminin E. glycosaminoglycans 18. Gap junctions are to animal cells as _____________ are to plant cells? A. middle lamella B. hemidesmosomes C. plasmodesmata D. primary cell walls E. tight junctions 19. Which of the following components of signal reception and transduction is NOT required for the bacterial two-component regulatory system for metabolizing these nitrogenous waste products? A. NarQ receptor B. NarL transcriptional activator C. a protein kinase D. metabolic enzymes E. ligand-gated calcium channel

20. What do enzyme-linked receptors and growth factor receptors have in common? A. both possess kinase activity when bound to a signal hormone B. both regulate specific G proteins when bound to a hormone C. both act as transcription factors D. both regulate the transport of ions through the channels E. both seldom affect the expression of genes within the nucleus 21. Which of the following represents the correct sequence of events in the cAMP signal transduction pathway? A. G protein → cAMP → adenylyl cyclase → protein kinase A → cell response B. G protein → adenylyl cyclase → protein kinase A → cAMP → cell response C. G protein → protein kinase A → adenylyl cyclase → cAMP → cell response D. G protein → adenylyl cyclase → cAMP → protein kinase A → cell response E. adenylyl cyclase → G protein → cAMP → protein kinase A → cell response 22. ____________ are proteins that attach animal cells to the ECM A. Cadherins B. integrins C. occludins D. tight junctions E. desmosomes 23. Which of the following statements comparing hemidesmosomes with desmosomes is TRUE? A. Hemidesmosomes are anchorage junctions but desmosomes are not B. Hemidesmosomes interact with actin filaments while desmosomes interact with intermediate filaments C. Both hemidesmosomes and desmosomes associate with integrin, but not cadherin molecules D. Hemidesmosomes anchor cells to the ECM while desmosomes anchor cells to other cells E. Hemidesmosomes are found in plant cells while desmosomes are found in animal cells 24. Which of the following occurs during anaphase I? A. chromosomes cluster at the two poles of the cell B. crossing over occurs C. chromosomes align down the center of the cell D. one homologue of each homologous chromosome moves towards a pole 25. During which phase of the cell cycle do the cytoplasm and chromosomes separate into two distinct cells? A. C B. G1 C. G2 D. S E. M 26. Match the change in chromosome structure on the left with the appropriate description on the right i. simple translocation ii. inversion

a. moving of a segment of a chromosome to a different chromosome b. exchange of pieces between two different chromosomes

iii. reciprocal translocation A. i=a; ii=b; iii=c B. i=c; ii=a; iii=b C. i=b; ii=a; iii=c D. i=c; ii=b; iii=a E. i-a; ii=c; iii=b

c. region of a chromosome is flipped into the opposite orientation

27. In humans the diploid number of chromosomes is 46. The haploid number is 23. Prior to mitosis in the cell cycle, the cell is in the G2 phase. Which of the statements is true? A. the homologous chromosomes are lined up on the equator B. the homologous chromosomes have all been copied through DNA replication C. the homologous chromosomes have been pulled to their respective poles by the spindle apparatus D. the homologous chromosomes have not been replicated yet E. the homologous chromosomes are now in the haploid or n condition 28. A small number of surface receptors can ultimately generate a large intracellular response, as each step of the pathway is often expanded by A. enzymic receptors B. gated ion channels C. signal amplifications D. G protein linked receptors 29. If an organism is diploid and has 32 chromosomes, how many chromatids would it have in the G2 phase of the cell cycle? A. 16 B. 32 ` C. 64 D. 128 E. none are correct 30. The interaction of DNA with the nuclear matrix does all of the following EXCEPT A. help form the radial loop domains B. allow DNA to be condensed in an identical pattern in all individuals of a species C. help wrap DNA around the histones D. bind radial loop domains to the inner surface of the nuclear membrane 31. Replicate copies of each chromosome are called __________ and are joined at the __________ A. homologues/centromere B. sister chromatids/kinetochore C. sister chromatids/centromere D. homologues/kinetochore 32. In __________, the kinetochore spindle fibers bind to one side of the centromere while in _______, the kinetochore spindle fibers attach to both sides of the centromere A. mitosis/meiosis I B. meiosis I/meiosis II C. meiosis II, mitosis

D. meiosis II/meiosis I 33. Synapsis is the process whereby A. homologous pairs of chromosomes separate and migrate toward a pole B. homologous chromosomes exchange chromosomal material C. homologous chromosomes become closely associated D. the daughter cells contain half of the genetic material as that of the parent cell 34. The protein that participate in the functioning of the checkpoints for cell cycle control is/are __________ and regulation is/are _________________ A. p53, retinoblastoma/histones B. histones/ p53, retinoblastoma C. histones/cyclins and cyclin dependent kinases D. cyclins and cyclin dependent kinases/p53, retinoblastoma E. p53, retinoblastoma/ cyclins and cyclin dependent kinases 35. In a haploid dominant species A. the multicellular organism is diploid and the gametes are haploid B. the multicellular organism is haploid and the gametes are diploid C. diploid cells are produced by mitosis and haploid cells are produced by meiosis D. the zygote is haploid E. the multicellular organism is haploid and the zygote is diploid 36. What proteins are used to control cell growth specifically in multicellular eukaryotic organisms? A. Cdk B. MPF C. cyclins D. growth factors 37. Which of the following sequence of cell-cycle phases is characteristic of eukaryotes? A. G to S to M B. S to M to C C. G1 to G2 to S to C D. G1 to S to G2 to M to C E. G1 to G2 to G3 to S to C 38. Microtubules become shorter, pulling chromatids to the ends of spindle, during A. anaphase B. interphase C. metaphase D. prophase E. telophase 39. Plant cells typically achieve cytokinesis by A. binary fission B. forming a cell plate across the middle of the cell C. forming a cleavage furrow that pinches the cell in two D. chromosome condensation

E. chromosome elongation 40. If a somatic cell has 32 chromosomes prior to S and undergoes mitosis followed by cytokinesis, each new daughter cell will have how many chromosomes? A. 64 B. 32 C. 16 D. 8 ANSWER KEY 1. A 2. E 3. C 4. A 5. B 6. B 7. B 8. E 9. B 10. C 11. D 12. E 13. A 14. B 15. B 16. D 17. B 18. C 19. D 20. A 21. D 22. B 23. D 24. D 25. A 26. E 27. B 28. C 29. C 30. C 31. C 32. B 33. C 34. D 35. E 36. D 37. D 38. A

39. B 40. B...