Bio Molecular Genetics Review Name: Period: Date:

Transcription

1 AP Bio Molecular Genetics Review Name: Period: Date: 1. Suppose that in studies of genes on the same chromosome you find the following recombination frequencies: In this case it would be proper to say that a, c, and b are a. linked genes. b. different alleles of the same gene. c. alternative alleles that are not physically possible since the numbers do not add up. d. linked genes that are not physically possible since the numbers do not add up. e. three of the possible alleles for determining a particular trait. 2. Which process generally is the cause for production of recombinant offspring for two genes on the same chromosome? a. movement of transposable elements b. pairing of nonhomologous chromosomes c. gene duplication d. exon shuffling e. crossing-over between homologous chromosomes 3. In Drosophila melanogaster there is a sex-linked gene for eye color that is found only on the X chromosome. The allele for red eye color (X w+ ) is dominant over the allele for white eye color (X w ). You examine a vial of 100 flies that are all offspring from a single genetic cross. You find both red-eyed females and white-eyed females as well as both red-eyed males and white-eyed males. The genotypes of the parents were a. X w+ X w+ ; X w Y. b. X w+ X w ; X w Y. c. X w X w ; X w+ Y. d. X w+ X w ; X w+ Y. 4. The change in the chromosomes depicted between the top and the bottom in the figure above represents a(n). a. inversion b. duplication c. reciprocal translocation d. deletion e. none of these 5. Examine the pedigree in the figure above, where individuals that have the genetic condition being tested are marked with filled squares or circles. Which of the following inheritance patterns is most likely correct for this condition? a. autosomal dominant b. X-linked recessive c. X-linked dominant d. cytoplasmic inheritance e. autosomal recessive 6. What does transformation involve in bacteria? a. the creation of a strand of DNA from an RNA molecule b. the creation of a strand of RNA from a DNA molecule c. the infection of cells by a phage DNA molecule d. the type of semiconservative replication shown by DNA e. assimilation of external DNA into a cell

2 7. What kind of chemical bond is found between paired bases of the DNA double helix? a. hydrogen b. ionic c. covalent d. sulfhydryl e. phosphate 8. During DNA replication, DNA ligase is most active on the lagging strand. Why? a. The lagging strands contain more short DNA segments than the leading strand, and these short segments are joined together by DNA ligase. b. The lagging strand is synthesized more slowly, and DNA ligase speeds up the DNA polymerase. c. The lagging strand synthesizes DNA in the 3' 5' direction. d. The lagging strand requires DNA ligase to couple the RNA primer to the Okazaki fragments. e. The lagging strand has no RNA primase activity; it is replaced by DNA ligase. Use the figure above for the following question. 9. In the figure above, representing transcription, the item labeled "C" is a. the nontemplate strand. b. RNA-DNA hybrid. c. the template strand. d. DNA double helix. e. the RNA copy. 10. Precursor-mRNA (pre-mrna) typically exists a. only in prokaryotes. b. in both the nucleus and cytoplasm of eukaryotes. c. only in the cytoplasm of eukaryotes. d. in both prokaryotes and eukaryotes. e. only in the nucleus of eukaryotes. 11. Substitution of one base pair for another in a coding region of a gene can result in a mutation where the changed codon codes for a different amino acid than was previously coded for. a. missense b. chromosomal c. frameshift d. silent e. nonsense 12. Insertion of two bases into the coding region of a gene just after the start codon of a gene will result in a mutation. a. missense b. chromosomal c. frameshift d. silent e. nonsense

3 13. Assume that an mrna molecule is made beginning complementary to this DNA sequence: 3' CTTACATGGCATCC 5' See the genetic code table above. The third codon (counting the start codon as the first codon) directs incorporation of which amino acid in the polypeptide? a. cysteine b. methionine c. threonine d. histidine e. arginine 14. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be a. 5' TTG-CTA-CAG-TAG 3'. b. 3' AAC-GAC-GUC-AUA 5'. c. 5' AUG-CTG-CAG-TAT 3'. d. 3' AAA-AAT-ATA-ACA 5'. e. 3' AAA-GAA-TAA-CAA 5'. 15. Small circles of DNA that occur in bacteria in addition to the main circular chromosomal DNA molecule are called: a. transformants. b. plastids. c. plasmids. d. plasmitrons. e. b, c and d only 16.Viruses are composed of only a. proteins. b. carbohydrates and proteins. c. proteins and nucleic acids. d. nucleic acids. e. carbohydrates, proteins, lipids, and nucleic acids. 17. The series of events from infection of one cell through the release of progeny phages from broken, open, or lysed cells is called a. lytic cycle. b. lysogenic cycle. c. Krebs cycle. d. citric acid cycle. e. a and b only 18. Why are viruses referred to as obligate parasites? a. They cannot reproduce outside of a host cell. b. Viral DNA always inserts itself into host DNA. c. They invariably kill any cell they infect. d. They can incorporate nucleic acids from other viruses. e. They must use enzymes encoded by the virus itself. 19. Why do RNA viruses appear to have higher rates of mutation? a. RNA nucleotides are more unstable than DNA nucleotides. b. Replication of their genomes does not involve the proofreading steps of DNA replication. c. RNA viruses replicate faster. d. RNA viruses can incorporate a variety of nonstandard bases. e. RNA viruses are more sensitive to mutagens. Refer to the treatments listed below to answer the following questions. You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent. I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious II. filtering the substance to remove all elements smaller than what can be easily seen under a light microscope III. culturing the substance by itself on nutritive medium, away from any plant cells IV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious

4 20. If you already knew that the infectious agent was either bacterial or viral, which treatment would allow you to distinguish between these two possibilities? a. I b. II c. III d. IV e. either II or IV 21. Suppose the laci repressor gene were permanently silenced by an alteration to the DNA sequence. What would be the impact on the function of the lac operon? a. The lac operon would be transcribed but at a low level. b. The lac operon would be transcribed at a high level. c. There would be no real impact on lac operon expression. d. The lac operon would only be expressed when lactose was present. e. The lac operon would not be expressed even when lactose was present. 22. The lactose operon is likely to be transcribed when a. there is more glucose in the cell than lactose. b. the cyclic AMP levels are low. c. there is glucose but no lactose in the cell. d. the cyclic AMP and lactose levels are both high within the cell. e. the camp level is high and the lactose level is low. 23. How does active CAP induce expression of the genes of the lactose operon? a. It terminates production of repressor molecules. b. It degrades the substrate allolactose. c. It stimulates splicing of the encoded genes. d. It stimulates the binding of RNA polymerase to the promoter. e. It binds steroid hormones and controls translation. 24. Muscle cells and nerve cells in one species of animal owe their differences in structure to a. having different genes. b. having different chromosomes. c. using different genetic codes. d. having different genes expressed. e. having unique ribosomes. 25. Two potential devices that eukaryotic cells use to regulate transcription are a. DNA methylation and histone amplification. b. DNA amplification and histone methylation. c. DNA acetylation and methylation. d. DNA methylation and histone acetylation. e. histone amplification and DNA acetylation. 26. Tumor suppressor genes a. are frequently overexpressed in cancerous cells. b. are cancer-causing genes introduced into cells by viruses. c. can encode proteins that promote DNA repair or cell-cell adhesion. d. often encode proteins that stimulate the cell cycle. e. all of the above 27. Which of the following is an example of post-transcriptional control of gene expression? a. the addition of methyl groups to cytosine bases of DNA b. the binding of transcription factors to a promoter c. the removal of introns and splicing together of exons d. gene amplification during a stage in development e. the folding of DNA to form heterochromatin 28. Why would researchers want to have both genomic libraries and cdna libraries from a particular organism? a. The genomic library is generally too big to be helpful; a cdna library, being smaller, is much easier to study. b. A cdna library will be the same in every cell; the genomic library tells researchers which genes are being expressed in individual cell types. c. The cdna library helps us understand how retroviruses work; the genomic library does not. d. The cdna library is a lot easier to clone than a genomic library. e. A genomic library will be the same in every cell; the cdna library tells researchers which genes are being expressed in individual cell types.

5 29. What is/are the advantage(s) of a polymerase chain reaction? a. PCR allows for the mass-production of a specific DNA sequence without cloning. b. PCR permits scientists to target a single copy of a single gene among millions of other sequences. c. PCR allows scientists to study DNA from samples of finite amounts, such as from fossils, or small tissue samples left at a crime scene. d. a and b only e. a, b, and c. 30. A principal problem with inserting an unmodified mammalian gene into a bacterial plasmid, and then getting that gene expressed in bacteria, is that a. prokaryotes use a different genetic code from that of eukaryotes. b. bacteria translate polycistronic messages only. c. bacteria cannot remove eukaryotic introns. d. bacterial RNA polymerase cannot make RNA complementary to mammalian DNA. e. bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible with mammalian DNA. 31. Which of the following is used to make complementary DNA (cdna) from RNA? a. restriction enzymes b. gene cloning c. DNA ligase d. gel electrophoresis e. reverse transcriptase 32. Which of the following separates molecules by movement due to size and electrical charge? a. restriction enzymes b. gene cloning c. DNA ligase d. gel electrophoresis e. reverse transcriptase Use Figure 20.3 to answer the following questions. The DNA profiles below represent four different individuals. Figure Which of the following statements is consistent with the results? a. B is the child of A and C. b. C is the child of A and B. c. D is the child of B and C. d. A is the child of B and C. e. A is the child of C and D. 34. Which of the following are probably siblings? a. A and B b. A and C c. A and D d. C and D e. B and D

6 Use the figure below to answer the following questions. 35. In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" nitrogen ( 15 N) and then transferred them to a medium containing 14 N. Which of the results in Figure 16.1 would be expected after one round of DNA replication in the presence of 14 N? Answer 1. A 2. E 3. B 4. C 5. B 6. E 7. A 8. A 9. E 10. E 11. A 12. C 13. E 14. E 15. C 16. C 17. A 18. A 19. B 20. C 21. B 22. D 23. D 24. D 25. D 26. C 27. C 28. E 29. E 30. C 31. E 32. D 33. B 34. D 35. D