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Unformatted text preview: Bio2600: Introduction to Cell Biology Nov., 2007 EXAM 3 Section 1: Complete each sentence with one of the two words shown in the square brackets [A. / B.]. 1. The human genome is co mprised of 23 pairs of chromosomes, which means that each cell has (A. 23/B. 46) centromeres. 2. If GAU is the anticodon, then the codon it recognizes is [A. AUC /B. CUA ]. 3. In eucaryotic cells, t he assembly of the general transcription factors begins with the binding of the factor [A. TFIID/B. TFIIH] to DNA, causing a dramatic local distortion in the DNA. 4. Histone [A. acetylase/B. deacetylase] is an enzyme that modifies histones and renders the DNA less accessible to general transcription factors. 5. The segments of primary RNA that are cleaved off by spliceosomes are called [A. exons/B. introns]. 6. The codon GCA encodes the amino acid [A. Leu/ B. Ala]. 7. The [A. large/ B. smal l] subunit of a ribosome is the first to interact with new mRNAs. 8. [A. Depurination/B. Deamination] is a common type of DNA damage that, if not repaired, can lead to the loss of a nucleotide and possibly a shift in the reading frame. 9. The [A. unipolar/B. bi polar] nature of a myosin thick filament is essential for muscle contraction. 10. The drug colchicine [A. prevents microtubule formation / B. stabilizes microtubules]. 11. Many bacterial genes contain a region known as a(n) [A. operator/B. promoter] to which a specific gene regulatory protein (not sigma) binds. 12. The enzyme Primase can polymerize [A. ribon ucleotides/ B. deoxy ribon ucleotides] to create the small primer used by DNA polymerase. 13. A major signal leading to protein degradation is the addition of [A. a phosphate/B. ubiquitin]. 14. Sequence information primarily residing in [A. introns/ B. exons] are used to determine the splice site. 15. When bidirectional rep lication forks from adjacent origins meet, a leading strand always runs into [A. a lagging strand/B. a leading strand]. 16. During skeletal-muscle contraction, the distance between the Z lines of a sarcomere [A. increases/ B. decreases]. 17. A string of nucleosomes can coil up to form a (A. 50 nm/ B. 30 nm) chromatin fiber. Page 1, v3 Section 2: Multiple Choice. Select the single best answer based on your knowledge of cell biology. 18. Mismatch repair of DNA A. usually occurs on newly replicated DNA. B. involves cleavage of the DNA backbone to excise a small stretch of single-stranded DNA containing a mispaired base. C. uses the proof reading capability of DNA polymerase I. D. A and B E. A, B and C. 19. There are many kinds of actin binding proteins including ones that do all of the following EXCEPT A. cross-link actin filaments B. sequester actin filaments C. bundle actin filaments D. cap actin filaments E. severe actin filaments 20. The following is a curve representing polymerization of tubulin dimers into microtubules. Based on this diagram, a b c % dimers in tubules time A. a lag phase (a) occurs because nucleation is rate limiting B. once nucleated, a rapid rising phase (b) occur as tubulin dimers are added to the...
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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