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Unformatted text preview: Bio2600:Introduction to Cell Biology Sept., 2007 EXAM 1 Section 1: Complete each sentence with one of the two words found in the square brackets. 1. [A. True/B. False] The hydrophobic forces that hold a membrane together are essentially identical to the hydrophobic forces that drive protein folding. 2. When using a channel protein, an ion always flows [A. up/B. down] its concentration gradient. 3. Disulfide bonds are created between two [A. Met /B. Cys] residues. 4. A normal cell is relat ively [A. permeable/ B. impermeable] to Cl- ions. 5. At the dendritic synapses, neurons can receive excitatory stimuli using [A. GABA/B. acetylcholine] as a neurotransmitter. 6. In a protein with a si ngle alpha-helix transmembrane domain, most of the amino acids in this region are [A. hydrophobic/B. hydrophilic]. 7. [A. True/B. False]. A plasma membrane of a cell has thousands of transmembrane proteins and the majority of these are anchored to the cytoskeleton, nevertheless, the membrane itself remains fluid. 8. Fatty acid chains that have no double bonds are considered [A. saturated/B. unsaturated]. 9. A catalyst for a chemi cal reaction [A. decreases/B. increases] the activation energy of a reaction. 10. The equation that describes the resting membrane potential is known as the [A. Fick Equation/ B. Nearst Equation.] 11. Secondary structures i n proteins are stabilized by H-bonds between carbonyl and amine groups of [A. the main chain/B. amino acid side chains]. 12. In the plasma membrane, phospholipid molecules are organized into a bilayer such that the [A. polar/B. nonpolar) regions are at the membrane surface. 13. Compared to water, carbon dioxide (CO 2 ) will diffuse [A. more/B. less] rapidly into the cell. 14. If the membrane potent ial moves further away from zero (becomes more negative) the cell is said to be [A. depolarized/B. hyperpolarized]. 15. An example of a basic polar amino acid is [A. Arg/B. Glu]. Section 2: Multiple Choice: Select the best answer (a to e) for each question based on your knowledge of Cell Biology. Page 1, v1 16. Cell membrane proteins function as A. receptors B. enzymes C. transporters D. channels E. all of the above 17. The diagram below depicts a cell with a negative resting membrane potential. Ion X is distributed such that it is four times more concentrated outside then inside of the cell. Ion Y is twice as concentrated inside then outside of the cell. Based on this diagram which statement below is correct?- + Y+ X+ X+ Y+ A. Both electrical and chemical gradients tend to move X into the cell. B. For Y, both electric and the chemical gradients tends to force Y out of the cell. C. For X, the chemical gradient tends to force X out of the cell but this is counteracted by the electrical gradient keeping X in the cell....
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This note was uploaded on 04/27/2008 for the course BIO 2600 taught by Professor Vanburkem during the Fall '08 term at Wayne State University.
- Fall '08
- cell biology