Chapter 16 DNA Replication Practice Test, Study notes of Genetics

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Chapter 16 Practice Test

Name___________________________________

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

1)Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA_?_

A)the rate of replication B)the frequency of A vs. T nucleotides C)the diameter of the helix D)the bond angles of the subunits E)the sequence of nucleotides

2)Why does the DNA double helix have a uniform diameter? 2) A)Deoxyribose sugars bind with ribose sugars. B)Nucleotides bind with nucleoside triphosphates. C)C nucleotides pair with A nucleotides. D)Purines pair with pyrimidines. E)Nucleotides bind with nucleosides.

3)What is meant by the description "antiparallel" regarding the strands that make up DNA? 3) A)The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. B)One strand is positively charged and the other is negatively charged. C)One strand contains only purines and the other contains only pyrimidines. D)The twisting nature of DNA creates nonparallel strands. E)Base pairings create unequal spacing between the two DNA strands.

4)In E. coli , there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?

A)No proofreading will occur. B)No replication fork will be formed. C)Replication will occur via RNA polymerase alone. D)Replication will require a DNA template from another source. E)The DNA will supercoil.

5)Which enzyme catalyzes the elongation of a DNA strand in the 5'3' direction? 5) A)DNA polymerase III B)helicase C)DNA ligase D)topoisomerase E)primase

6)What determines the nucleotide sequence of the newly synthesized strand during DNA replication? 6) A)the relative amounts of the four nucleoside triphosphates in the cell B)the particular DNA polymerase catalyzing the reaction C)the nucleotide sequence of the template strand D)the primase used in the reaction E)the arrangement of histones in the sugar phosphate backbone

7)To repair a thymine dimmer by nucleotide excision repair, in which order do the necessary enzymes act?

A)helicase, DNA polymerase I, DNA ligase B)exonuclease, DNA polymerase III, RNA primase C)endonuclease, DNA polymerase I, DNA ligase D)DNA polymerase I, DNA polymerase III, DNA ligase E)DNA ligase, nuclease, helicase

8)What is the function of DNA polymerase III? 8) A)to unwind the DNA helix during replication B)to add nucleotides to the end of a growing DNA strand C)to seal together the broken ends of DNA strands D)to rejoin the two DNA strands (one new and one old) after replication E)to degrade damaged DNA molecules

9)Which of the followingremoves the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments?

A)helicase B)DNA polymerase I C)DNA polymerase III D)primase E)ligase

10)Which of the followingseparates the DNA strands during replication? 10) A)ligase B)DNA polymerase I C)primase D)helicase E)DNA polymerase III

11)Which of the followingcovalently connects segments of DNA? 11) A)primase B)helicase C)ligase D)DNA polymerase I E)DNA polymerase III

12)Which of the followingsynthesizes short segments of RNA? 12) A)DNA polymerase III B)helicase C)ligase D)DNA polymerase I E)primase

20)If a cell were unable to produce histone proteins, which of the following would be a likely effect? 20) A)Spindle fibers would not form during prophase. B)There would be an increase in the amount of "satellite" DNA produced during centrifugation. C)Amplification of other genes would compensate for the lack of histones. D)Pseudogenes would be transcribed to compensate for the decreased protein in the cell. E)The cell's DNA couldn't be packed into its nucleus.

21)Why do histones bind tightly to DNA? 21) A)Histones are highly hydrophobic, and DNA is hydrophilic. B)Histones are covalently linked to the DNA. C)Histones are negatively charged, and DNA is positively charged. D)Both histones and DNA are strongly hydrophobic. E)Histones are positively charged, and DNA is negatively charged.

22)Which of the following statements is true of chromatin? 22) A)Euchromatin is not transcribed, whereas heterochromatin is transcribed. B)Heterochromatin is composed of DNA, whereas euchromatin is made of DNA and RNA. C)Both heterochromatin and euchromatin are found in the cytoplasm. D)Heterochromatin is highly condensed, whereas euchromatin is less compact. E)Only euchromatin is visible under the light microscope.