Cowdin AP Bio Chp 9. Practice Test – Flashcards

A-T base pairs in a DNA double helix A. form three hydrogen bonds with each other. B. are of a different length than G-C base pairs. C. are chemically distinct from G-C base pairs. D. are more heat stable than G-C base pairs. E. are not accessible to DNA binding proteins.

Which of the following statements about DNA structure is false? A. The 3′ end is phosphorylated. B. It is a right-handed helix. C. It is a double-stranded helix. D. It is antiparallel (the two strands run in opposite directions). E. It has a uniform diameter.

The polymerase chain reaction requires A. cyclical denaturation and binding of double-stranded DNA. B. one specific DNA oligonucleotide as a primer. C. a heat resistant RNA polymerase. D. primase. E. single-stranded DNA as a template.

In order to show that DNA in cell extracts is responsible for genetic transformation in of bacteria, important corroborating evidence should indicate that _______ also destroyed transforming activity. A. enzymes that hydrolyzed polysaccharides B. enzymes that hydrolyzed DNA C. enzymes that hydrolyzed proteins D. boiling E. enzymes that hydrolyze RNA

If guanine makes up 20 percent of the bases in a sample of double-stranded DNA, what percentage of the bases would be cytosine? A. 40 B. 15 C. 60 D. 20 E. 30

If adenine makes up 20 percent of the bases in a sample of double-stranded DNA, what percentage of the bases would be cytosine? A. 70 B. 30 C. 15 D. 40 E. 35

A silent mutation A. would likely not affect the activity of a protein. B. would not affect the primary structure of a protein. C. is a result of a change in a codon for an amino acid in a protein to a stop codon. D. results in a protein that is truncated from the N-terminal end. E. results in a shorter mRNA transcript of the gene.

In many eukaryotes, there are repetitive sequences at the ends of chromosomes called telomeres. After successive rounds of DNA replication, the _______ strand becomes shorter. In some cells, an enzyme called _______ repairs the shortened strand. A. lagging; telomerase B. leading; telomerase C. leading; DNA polymerase I D. leading; replicase E. lagging; DNA polymerase I

Which of the following mutations is not a chromosomal mutation? A. Duplications B. Point mutations C. Translocations D. Large deletions E. Inversions

A mutant strain of yeast grew well at 20°C, but not at 37°C, whereas the wild-type strain grew well at both temperatures. The mutation is an example of a A. gain-of-function mutation. B. missense mutation. C. frame-shift mutation. D. point mutation. E. conditional mutation.

Which of the following mechanisms does not cause spontaneous mutations to occur? A. A mutagen causing a permanent change in DNA sequence B. Errors during meiosis C. Errors during DNA replication D. DNA pairing with the wrong base E. Spontaneous chemical reactions during DNA replication

Which of the following mutagens may result in an induced mutation? A. Ultraviolet radiation B. Benzopyrene C. Aflatoxin D. Free radicals E. All of the above

The 5′ end of a DNA strand A. does not contain a phosphate group on the ribose. B. is part of the growing strand during DNA replication. C. could contain the base, uridine. D. is the end of both strands of DNA in a double helix. E. is part of the template strand during DNA replication.

Which of the following is not used for DNA synthesis? A. dATP B. dUTP C. dTTP D. dCTP E. dGTP

Mutations A. are always deleterious. B. occur at the same rate for all bases. C. can arise from errors in DNA replication. D. are of no importance to evolution. E. are always caused by mutagens.

Which of the following statements about repairing errors in DNA replication is false? A. After replication, mismatch repair proteins excise a small portion of the DNA molecule that includes the mismatched bases. B. During DNA replication, guanine may be incorrectly paired with thymine, requiring repair. C. DNA polymerase I replaces the removed section of DNA with the correct bases. D. During DNA replication, DNA polymerase proofreads the growing strand and replaces incorrectly paired nucleotides before continuing replication. E. DNA topoisomerase repairs the remaining nicks in the newly replicated strand.

The replication of lagging strands of DNA differs from the replication of leading strands in that A. DNA is replicated as short fragments. B. RNA primers are required. C. DNA ligase is needed. D. primase is required. E. All of the above

If adenine makes up 20 percent of the bases in a sample of double-stranded DNA, what percentage of the bases would be uracil? A. 0 B. 30 C. 10 D. 15 E. 20

In multicellular organisms A. all mutations are point mutations. B. somatic mutations may be passed to daughter cells by mitosis. C. somatic mutations are passed on to offspring produced by sexual reproduction. D. meiosis is not required for the transmission of germ line mutations to the next generation. E. all mutations produce phenotypic changes.

A point mutation A. is always silent. B. does not occur in noncoding regions of DNA. C. is a change in a single nucleotide of DNA. D. is not transmitted to daughter cells. E. is a result of a chromosomal deletion.