Factors Affecting Plasma Membrane Rigidity and Cellular Processes - Prof. Arthur N. Popper, Exams of Biology

Download Factors Affecting Plasma Membrane Rigidity and Cellular Processes - Prof. Arthur N. Popper and more Exams Biology in PDF only on Docsity! , i ^ [ / Q5 BIOLOGY 105, December 17, 1991. Final Examination - A. N. Popper and A. J. Olek Answer each question on the two answer sheets provided. Please put your name on EACH answer sheet now. Only turn in the answer sheets to YOUR ta. Read each question carefully and fill in the box on the answer sheets with the best answer! This exam has 12 pages (including the two answer sheets) 1. Plasma membranes will vary in rigidity depending upon various factors. Which of the following factors is likely to affect that rigidity? a) the saturation level of fatty acids; b) the number of transmembrane channels; c) the presence of cellulose in the plasma membrane; d) the presence of cholesterol in the membrane 2. The rate of diffusion across a membrane will most likely be affected by? a) age of the membrane; b) number of transmembrane active channels; c) proton pumps; d) concentration gradient across the membrane 3. You have a container divided evenly by a membrane that is only permeable to water. The left side of the container has a 15% sucrose solution while the right side of the membrane has a 2% sucrose solution. Which of the following is likely to occur? a) water will flow from the right side of the membrane to the left; b) water will flow from the left side of the membrane to the right; c) there will be no water movement; d) the results are unpredictable 4. Molecules of a solute can move up a concentration gradient with energy expenditure in the process known as: a) facilitated diffusion; b) endocytosis; c) osmosis; d) active transport 5. In the Na + -K + pump: a) two ions of K + are moved into the cell and three ions of Na + are moved out of the cell; b) four molecules of ATP are reduced to ADP + P; c) the channel collapses on the Na; d) calcium is necessary or the pump will not work 6. Which of the following processes results in the movement of large particles out of a cell? a) endometriosis; b) exocytosis; c) phagocytosis; d) pinocytosis 7. The atomic mass of a molecule is: a) the combination of the atomic number and weight; b) the number of protons and the number of neutrons; c) the number of neutrons and number of electrons; d) the number of protons and the number of electrons 8. Carbon 14 and tritium are: a) atoms used to make nuclear bombs; b) artificial elements; c) isotopes of other naturally occurring atoms; d) components of naturally occurring glucose 9. Which of the following would be your most fundamental need if you wanted to build a very simple plasma membrane? a) cellulose; b) phospholipids; c) sugars; d) electrolytes 1 10. Phospholipids contain: a) proteins and alcohols; b) fatty acids and proteins; c) glucose and glycerol; d) fatty acids and alcohol 11. In order to insure that polar molecules can move across a plasma membrane, the membrane contains: a) transmembrane proteins; b) cholesterol; c) glycerol; d) receptors 12. When there is a very high concentration gradient across a cell membrane, the rate of diffusion across the cell membrane is NOT likely to be affected by: a) number of channels in the membrane; b) surface area of the membrane; c) sodium-potassium pump 13. While of the following is NOT a role of the plasma membrane of a cell? a) barrier; b) receptor of information; c) cell identification; d) site for proton pumps 14. In a biochemical reaction, an enzyme: a) is permanently changed; b) lowers the energy of activation of the reaction; c) changes the pH of the solution; d) changes the temperature of the reactants 15. In photosynthesis: a) light is needed for the Calvin process; b) water serves to carry the electrons around the system; c) ATP is produced by ferrodoxin; d) light raises the energy of electrons in chlorophyll 16. In the light reaction of photosynthesis: a) glucose is manufactured from water; b) oxygen is released by the breakdown of water; c) protein Z takes electrons from photosystem I and transfers them to photosystem II; d) energy loss produces heat which drives chemical reactions 17. Which does NOT occur during the 'dark cycle' of photosynthesis: a) glucose is manufactured; b) NADPH provides energy; c) carbon dioxide is used; d) ADP is converted to AMP 18. During the total process of cellular respiration: a) the net amount of ATP produced is 36 molecules; b) oxygen is released by the cell; c) proton pumps are manufactured by Golgi apparatus; d) chemiosmosis occurs on the endoplasmic reticulum 19. Which of the following does NOT occur during anaerobic metabolism? a) glucose is converted to a 3-carbon compound; b) ATP is used for energy; c) NADH is used for energy; d) acetyl Co-A is the final product before aerobic metabolism 20. Which of the following does NOT occur during the aerobic portion of metabolism? a) ethanol is produced; b) CC)2 is produced; c) O2 is an electron acceptor; d) citric acid is produced. 21. The process known as chemiosmosis does NOT include the involvement of: a) cytochromes; b) concentration gradients; c) proton pumps; d) Golgi apparatus Examine these structures to answer the next three questions a) b) c) U d) O o /H / ,1 37. Which of the above structures is a carboxyl group? 38. Which of the above structures is a phosphate group? 39. Which of the above structures is an amino group? 40. Which of the following is the best reason plant cells do not burst when placed in pure water? a) they are isotonic with respect to water; b) they have cell walls; c) 'they pinocytose water; d) their membranes are impermeable to water 41. Which of the following would probably NOT have been present in the primitive earth's atmosphere (approximately 3.5 billion years ago)? a) oxygen; b) methane; c) ammonia; d) hydrogen 42. Osmosis will occur when: a) solutes are present in two different concentrations; b) solutes are present in different concentrations and separated by a semipermeable membrane; c) hydrostatic pressure exists in one compartment; d) when the cell membrane is broken 43. Which of the following groups have no multicellular organisms as members (present day)? a) eukaryotes; b) prokaryotes; c) heterotrophs; d) autotrophs In the following five questions refer to the expression: R = D x A x A?/d 44. What is R? a) surface to volume ratio; b) concentration difference; c) rate of diffusion; d) diffusion constant 45. Why did multicellular organisms develop circulatory systems? a) to increase R; b) to decrease R; c) to increase cellular surface area; d) to increase D 46. All cells in a vertebrate are within 100 micrometers of a blood vessel (capillary). The best reason for this is: a) d is decreased; b) A is increased; c) D is increased; d) R is increased 47. Which of the following would NOT be a result of having an efficient pulmonary system? a) increased R; b) increased A; c) decreased d; d) increased D 48. Which of the following would be most influenced by having a stronger heart (capable of producing higher pressure)? a) increase *P; b) increased d; c) decreased d; d) increased A 49. Atmospheric air pressure will cause a mercury column to rise to a height of 760 mm. What is the partial pressure of oxygen in this room (in the same units)? a) 760; b) 0; c) 1520; d) 160 50. The partial pressure of oxygen in water is much lower than that of air. The best reason for this is: a) oxygen is not very soluble in water; b) microscopic plants consume most of the oxygen; c) nitrogen is the principal gas found in water; d) oxygen is immediately converted to H20 51. Which of the following correctly describes the linkage between nucleotide in RNA? a) phosphodiester bond between the 3' and 5' C of ribose groups; b) phosphodiester bond between the 1' and 5" C of ribose group; c) phosphodiester bond between the 1 C and the organic base; d) 3' and 4' C of glucose monomers 52. In general, which of the following would be the expected ratio for the number of adenine and thymine bases in the DNA present in any cell? a) 1:1; b) 1:2; c)2:l; d) none 53. Which of the following is NOT a stage of gene expression? a) transcription; b) mRNA processing; c) translation; d) DNA replication 54. Which of the following would NOT be involved in regulating protein synthesis? a) uncoiling DNA; b) mRNA processing; c) blocking the binding site for RNA polymerase; d) disrupting phosphodiester bonds of DNA 55. A principal difference between DNA and RNA is: a) RNA has 5 different bases; b) RNA has one base different from those of DNA; c) RNA cannot encode for proteins; d) RNA has no enzymatic activity 56. Which of the following is the MOST useful definition of a single "gene"? a) the nucleotide sequence of DNA that encodes for a polypeptide; b) the nucleotide sequence of DNA that encodes for a trait such as eye color; c) the part of the DNA that is expressed in any given cell; d) any part of DNA 57. Which of the following is NOT true about DNA? a) all nucleotide sequences in DNA encode for polypeptides; b) DNA is double-stranded in most cells; c) there is generally more than one gene on any piece of DNA; d) in non-dividing cells DNA does not leave the nucleus 58. In general, which of the following is TRUE for a non-dividing, eukaryotic, somatic cell? a) DNA is present as a single stranded nucleotide polymer; b) DNA is present as coiled structure composed of DNA and protein; c) DNA is in the same structure as DNA in a dividing cell; d) there are only 23 chromosomes 59. Which of the following is NOT an important step during mitosis? a) DNA replication; b) nuclear envelope breakdown; c) movement of the chromosomes; d) transcription 60. Which of the following is a major difference between mitosis and meiosis? a) DNA is not replicated during mitosis; b) there is genetic exchange between homologous chromosomes during meiosis; c) mitosis only occurs in reproductive cells; d) mitosis is much slower than meiosis 61. RNA polymerase was so named because: a) it enzymatically degraded RNA; b) it catalyzed the formation of peptide bonds at the ribosome; c) it created polymers of RNA from nucleotide subunits; d) it enzymatically degraded DNA 62. You are a detective and want to conclusively identify suspect X from suspect Y. Which of the following would the most helpful? a) compare the amino acid sequences of any protein from X and Y; b) compare the DNA in the gametes of X and Y; c) compare the DNA in the somatic cells of X and Y; d) compare: the RNA of X and Y 63. Alanine is considered a "neutral" amino acid. The best reason for this is: a) it's carboxyl group has a pH = 7; b) it's amine group has a pH=7; c) it's "R" group is not charged or polar; d) it gets along well with the neighbors 64. Which of the following would be the single most important difference between prokaryotes and eukaryotes. a) eukaryotes have internal membrane bound compartments; b) prokaryotes have ribosomes and eukaryotes do not; c) eukaryotes have a lipid cell membrane and prokaryotes have a cell wall instead; d) all prokaryotes obtain energy directly (are autotrophs) 65. Which of the following types of cells were the first to appear on primitive earth? a) autotrophs; b) heterotrophs; c) eukaryotes; d) plant cells 66. A major difference between a triglyceride and a phosphoglyceride is: a) one is saturated and the other is not; b) a phosphoglyceride has only two fatty acid "tails"; c) a phosphoglyceride is completely uncharged and non-polar; d) triglycerides are used exclusively to form cell membranes 67. Which of the following is correct about the "genetic code"? a) it is a code using a 1 base sequence; b) it is a code using a 2 base sequence; c) it is a code using a 3 base sequence; d) it is a code using a 4 base sequence 68. The codon can be considered the unit of the genetic code. It is found on which of the following? a) 3'-5' strand of DNA; b) 5'-3' strand of DNA; c) mRNA; d) tRNA 69. You are working for a biotech firm and are asked to build a protein that has a completely linear structure in water. Which of the following conditions would you employ? a) choose an amino acid sequence with just carboxyl groups; b) choose an amino acid sequence with "R" groups that alternate in charge; c) choose and amino acid sequence with "R" groups having the same charge; d) any sequence; all proteins have a linear structure in water 90. When one neuron sends a signal to another neuron, which of the following events is NOT likely to occur? a) calcium enters the presynaptic membrane; b) neurotransmitter is released from the presynaptic cell; c) receptors on the postsynaptic membrane bind with neurotransmitter; d) calcium is released from the postsynaptic receptors 91. Which of the following is a common neurotransmitter? a) acetylcholine; b) fumic acid; c) acetyl Co-A; d) ATP 92. Acetylcholinesterase (AcHase): a) breaks down acetyl Co-A; b) stops the action of acetylcholine; c) is never associated with neurons; d) converts acetylcholine to epinepherine. 93. Hormones: a) are never produced by neurons; b) are not found in the brain; c) are carried in the blood; d) are only found in adult humans. 94. Which of the following is NOT true about the pituitary gland? a) it is one of the largest organs of the body; b) it produces a hormone that affects water retention; c) it produces a hormone that affects milk production; d) it is stimulated by hormones produced in the hypothalamus 95. Steroid hormones: a) are made of many amino acids; b) affects protein reduction in a target cell; c) are water soluble; d) are only manufactured in reproductive organs. 96. Peptide hormones: a) are detected by special receptor molecules on the plasma membrane surface; b) only act on receptors in the spinal cord; c) passes through transmembrane channels in the plasma membrane; d) are only produced in the adrenal cortex 97. When we talk about feedback in the endocrine system we mean: a) hormones become a source of energy for glands; b) glands control the level of function of the brain; c) releasing factors stimulate production of other hormones; d) the brain monitors and controls the levels of hormones in the body 98. Which" of the following is true about the filtrate in kidney tubules? a) it is composed of water and small molecules; b) it is composed of blood and small molecules; c) it is derived from the lymphatic fluid; d) except for the amount of water it is very similar to the blood 99. After you ingested a meal with an excessive amount of salt (NaCl), which of the following would you NOT expect to happen? a) increased Na + would appear in the urine; b) increased urine output (urinate more); c) decreased aldosterone levels in the blood; d) increased ADH levels in the blood 100. Which of the following soft drinks is superior? a) Coke; b) Diet Coke; c) Caffeine-Free Diet Coke; d) Caffeine-Free Coke 10 BIOLOGY 105, December 17, 1991. 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