Bio 1710 Exam Ii 2005

Principles of Biology I Exam II, FALL ‘05

Name:_____________________________

Remember to read all of the possible answers for each question before choosing the BEST ANSWER. 1. Random motion causes a net movement of substances dissolved in water from regions where their concentration is high to regions where their concentration is lower. This process is called: a. active transport. b. osmosis. c. diffusion. d. facilitated diffusion. e. selective permeability. 2. Glucose in the bloodstream is allowed to enter red blood cells. This process does not require energy, is specific for glucose (other sugars cannot enter via this pathway) and the net movement is of glucose from the bloodstream (where it is at a relatively high concentration) into the cell (where the concentration is lower). This process is most likely to be an example of: a. active transport. b. osmosis. c. diffusion. d. facilitated diffusion. e. coupled transport. 3. A cell takes up sugar molecules from the surrounding fluid. Upon further study it is determined that 1) the sugar concentration in the cell is already higher than that of the surrounding medium, yet the cell continues to be able to take up more and 2) as each sugar molecule is taken up a molecule of sodium is also allowed to enter the cell. This process is likely to be an example of: a. active transport. b. coupled transport. c. diffusion. d. facilitated diffusion. e. endocytosis. 4. An intracellular receptor that, when activated, regulates the expression of a gene in the nucleus will likely have all but which of the following binding sites and/or domains? a. DNA binding domain. b. hormone (signal) binding domain. c. transcription activating domain. d. Inhibitor binding site. e. Such a receptor would likely have all four of the above sites/domains.

5. As a scientist you very carefully inject a small water-soluble blue dye molecule into a single cell of a piece of living human tissue. After a while you note that it has spread into adjacent cells. This most likely occurred because of a. active transport. b. gap junctions. c. tight junctions. d. osmosis. e. plasmodesmata. 6. A signal molecule released by one cell binds to receptors on target cells only in the immediate “neighborhood” and does not enter the blood stream. This is an example of: a. autocrine signaling. b. exocrine signaling. c. direct contact signaling. d. synaptic signaling. e. paracrine signaling. 7. Protein kinase cascades are often involved in: a. cell surface recognition. b. signalling pathways. c. anabolic pathways. d. catabolic pathways. e. photosynthesis. 8. The metabolic pathway we refer to as glycolysis is found in: a. bacteria. b. plants. c. animals d. all eukaryotes and eubacteria but not archaebacteria. e. all living organisms. 9. Electrons are transferred from a substrate molecule to NAD+, producing NADH and another product. The original substrate has undergone a/an ____ reaction. a. oxidation b. condensation c. reduction d. hydrolysis e. decarboxylation 10. In terms of thermodynamics, the term used to describe disorder is: a. kinetic energy b. enthalpy c. entropy d. free energy e. allosterism

11. When a reaction catalyzed by an enzyme is compared to the same reaction occurring without an enzyme, the: a. energy of the products has been reduced. b. energy of the reactants has been reduced. c. the change in free energy (∆G) has been decreased. d. the change in free energy (∆G) has been increased. e. the activation energy has been reduced. 12. A competitive inhibitor of an enzyme would likely: a. resemble the substrate. b. bind to the enzyme’s allosteric site. c. require calmodulin to act. d. require a G protein to act. e. require a protein kinase to act. 13. Which of the following is NOT commonly used in intracellular signalling pathways by cells? a. adenylyl cyclase b. G proteins c. calmodulin d. desmosomes e. All of the above are found in intracellular signaling pathways. 14. An example of a junction designed to prevent fluids (and other things) from penetrating around a cell (such as in the intestinal epithelial lining separating the gut from the capillaries) would be a/an: a. tight junction. b. desmosome. c. gap junction d. plasmodesmata. e. None of the above would function to prevent fluid penetration. 15. The phase of mitosis where you find the condensed chromosomes lined up along the equator of the cell is called: a. prophase. b. G1 c. metaphase d. G2 e. anaphase 16. The electron transport chain used to make ATP in photosynthesis is found: a. in the cytoplasm of mesophyll cells. b. in the mitochondrial matrix. c. in the chloroplast stroma. d. in the thylakoid membrane. e. in the plasma membrane of bundle sheath cells.

17. The electron transport chain of eukaryotic aerobic respiration pumps protons: a. into the cytoplasm. b. into the smooth ER. c. across the plasma membrane. d. into the intermembrane space of the mitochondrion. e. into the mitochondrial matrix. 18. During mitosis, the nucleus first “dissolves” during: a. prophase. b. G1 c. metaphase d. G2 e. anaphase 19. The division of the cytoplasm and organelles (in eukaryotic cells) occurs during: a. prophase. b. G1. c. cytokinesis. d. G2. e. anaphase. 20. The theoretical yield in ATP from oxidizing a glucose molecule completely to carbon dioxide and water through aerobic respiration is: a. 2. b. 6. c. 12. d. 32. e. 36. 21. Under conditions of very low oxygen, a human cell primarily uses _____ as the final electron acceptor: a. carbon dioxide. b. water. c. NAD+ d. pyruvate. e. Oxygen must always be used by human cells. 22. The electrons received by photosystem I in green plants are ultimately transferred to: a. water. b. FAD+. c. NAD. d. NADP+. e. oxygen.

23. A mutated gene that promotes cell division when not appropriate is called a/an: a. oncogene. b. protooncogene. c. tumor suppressor gene. d. growth factor gene. e. All of the above are correct answers. 24. A small molecule is determined to be able to cross the plasma membrane of a specific cell type. The properties of the process are 1) It is specific; 2) It requires energy in the form of ATP; and 3) It saturates. This is likely an example of: a. simple diffusion. b. active transport. c. bulk transport. d. facilitated diffusion. e. All of the above processes share these properties. 25. The actual C4 carbon fixation in a tropical grass plant occurs in the: a. mesophyll cells. b. bundle sheath cells. c. stoma. d. thylakoids. e. Answers A and B are both correct. 26. ATP is generated by both plants and animals using ATP synthase and a proton gradient. This process is called: a. excitation. b. electron absorbtion. c. substrate phosphorylation. d. chemiosmosis. e. electron transport. 27. The pigment(s) at the reaction center of both photosystems I and II of green plants is/are: a. chlorophyll a. b. chlorophyll b. c. carotenoids. d. cytochrome oxidase. e. All of the above are pigments found at these reaction centers. 28. The products of a certain reaction have a lower free energy level than the reactants. This reaction is best described as being: a. anabolic. b. catabolic. c. exergonic. d. endergonic. e. entropic.

29. CAM plants have adapted to arid climates by: a. utilizing only the dark reactions for photosynthesis. b. not using water as an electron donor for photosynthesis. c. using only bundle sheath cells for photosynthesis. d. eliminating stomata in their leaves. e. fixing carbon at night. 30. The final product of a metabolic pathway inhibits an early enzyme in the pathway. What term best describes this process? a. competitive inhibition. b. feedback inhibition c. cooperativity d. energy coupling e. intracellular signalling 31. Prokaryotes divide by a process known as: a. cytokinesis. b. mitosis. c. meiosis. d. transformation. e. binary fission. 32. The sister chromatids of a metaphase chromosome are connected at the: a. chiasma. b. centriole. c. centromere. d. centrosome. e. desmosome. 33. The chromosomes are replicated during what phase of the cell cycle? a. G1 b. anaphase c. S d. prophase e. G2 34. The chromosomes migrate toward the opposite poles of the cell during what phase of mitosis? a. prophase b. anaphase c. telophase d. metaphase e. cytokinesis

35. The final electron acceptor in green plants for photosystem II is: a. oxygen. b. water. c. NAD. d. NADP. e. photosystem I. 36. The particular array of chromosomes that an individual possesses is called their: a. karyotype. b. homologue. c. haploid. d. phenotype. e. mitotic complement. 37.Photosynthesis

a. b. c. d. e.

by plants uses what type of light most efficiently? infrared green blue ultraviolet Due to a range of accessory photosynthetic pigments, plants use nearly all wavelengths of light with equal efficiency.

38. The basic repeat unit or building block of eukaryotic chromatin is the: a. chromatid. b. nucleosome. c. histone. d. centromere. e. replisome. 39. Most genes that a higher eukaryotic cell is expressing (or might be required to express in the future) would be found in: a. euchromatin. b. kinechores. c. heterochromatin. d. centromeres. e. telomeres. 40. A human skin cell has a total of _____ chromosomes. a. 20 b. 23 c. 40 d. 46 e. 50

41. In the absence of oxygen, human cells produce lactate (lactic acid). The purpose of this is to: a. feed it into glycolysis. b. feed it into Kreb’s cycle. c. produce NADH. d. regenerate NAD+. e. allow chemiosmosis to occur. 42.The

ultimate electron acceptor in aerobic respiration is: a. oxygen. b. carbon dioxide. c. water. d. NADH. e. NADP.

43. The source of the electrons that pass through the photosystems during photosynthesis by green plants is: a. carbon dioxide. b. NADH. c. NADPH. d. water. e. rubisco. 44. An organism does not require any organic molecules as energy sources or for any other dietary requirement. This organism would likely be classified as a/an: a. hetereogroph. b. auxotroph. c. fermenter. d. anaerobe. e. autotroph. 45. Where (in a eukaryotic cell) does glycolysis take place? a. mitochondrial matrix b. cytoplasm c. nucleus d. mitochondrial inter-membrane space e. chloroplast 46. An egg is fertilized by a sperm to produce a single cell called a. a. binary fusion product b. spermatocyte. c. oocyte. d. Barr body. e. zygote.

47. The close association of homologous chromosomes during prophase I of meiosis is called: a. prophasian pairing. b. linkage. c. syngamy. d. diploidy. e. synapsis. 48. Haploid cells which are produced for the purpose of reproduction by diploid organisms are called: a. zygotes. b. somatic cells. c. gametes. d. chiasma. e. synapsis. 49. During meiosis, the proper order of the phases is: a. prophase, metaphase, telophase, anaphase. b. prophase, anaphase ,metaphase, telophase. c. metaphase, prophase, telophase, anaphase. d. prophase, metaphase, anaphase, telophase. e. anaphase, prophase, metaphase, telophase. 50. Chiasmata form during: a. anaphase I. b. prophase I. c. telophase II. d. prophase II. e. metaphase I. 51. With respect to meiosis, centromeres split during: a. metaphase I. b. prophase I. c. anaphase I. d. methaphase II. e. anaphase II. 52. A human cell in metaphase II of meiosis would have a total of ______ chromatids. a. 23 b. 96 c. 46 d. 46 pair e. None, the centromeres have already split.

53. Crossing over occurs during which phase of meiosis? a. Prophase I b. Metaphase I c. Anaphase II d. Telophase I e. Anaphase I