BIOL 3030 Practice Exam 40 Questions with Verified Answers,100% CORRECT

BIOL 3030 Practice Exam 40 Questions with Verified Answers Which enzyme untwists the parent strands of DNA during replication? - CORRECT ANSWER DNA helicase Tetrad analysis is a technique for a. determining base sequences in DNA b. mapping genes in organisms retaining the four meiotic products in one structure c. measuring the number of chromatids at meiosis d. separating neurospora mycelia - CORRECT ANSWER b. mapping genes in organisms retaining the four meiotic products in one structure The enzyme most directly concerned with catalyzing DNA synthesis - CORRECT ANSWER DNA polymerase What did Lederberg and Tatum's 1946 experiment show? a. That viruses are required for genetic exchange between bacterial cells b. That bacterial cells can be made to uptake bits of DNA from the experiment c. That genetic recombination in bacteria occurs at a very high rate d. That sexual recombination can occur between bacterial cells e. That genetic exchange between bacterial cells is a bidirectional process - CORRECT ANSWER d. That sexual recombination can occur between bacterial cells DNA and RNA are polymers of - CORRECT ANSWER nucleotides During transcription, the synthesis of the mRNA strand proceeds in which direction? - CORRECT ANSWER 5' to 3' Nucleosomes typically consist of which of the following? I. DNA II. Histones III. Microtubules a. I only b. II only c. I and III only d. II and III only e. I and II only - CORRECT ANSWER e. I and II only A StrR mutant: a. can grow in the presence of streptomycin b. can make its own streptomycin c. cannot grow in the presence of streptomycin d. cannot grow without streptomycin e. cannot make its own streptomycin - CORRECT ANSWER a. can grow in the presence of streptomycin Phage that can grow using either a lytic or lysogenic pathway are called a. virulent b. temperate c. intemperate d. transductant - CORRECT ANSWER b. temperate Analysis of bases of a nucleic acid sample yielded the following result: A, 32%; G, 17%; C, 18%; U, 33%. The sample is most likely a. single-stranded RNA b. double-stranded RNA c. single-stranded DNA d. double-stranded DNA - CORRECT ANSWER b. double-stranded RNA An example of a heritable disease that results from a biochemical defect in a nonenzymatic protein is: a. cystic fibrosis b. Lesch-Nyhan syndrome c. Alkaptonuria d. Tay-Sachs disease e. Phenylketonuria - CORRECT ANSWER a. cystic fibrosis The majority of naturally occurring DNA form is humans is a. Z form b. D form c. C form d. B form e. A form - CORRECT ANSWER d. B form Which enzyme is responsible for new strand elongation during DNA replication in E. Coli? a. DNA polymerase I b. TFIID c. DNA polymerase III d. DNA polymerase II e. RNA polymerase I - CORRECT ANSWER c. DNA polymerase III In yeast, the cross ab X ++ produces a tetrad having one ab spore, one ++, one a+, and +b spores. How would you classify this tetrad? a. nonparental ditype b. mating type a c. parental ditype d. tetratype - CORRECT ANSWER d. tetratype The RNAs that are used in eukaryotic translation include all of the following except a. 5S rRNA b. 28S rRNA c. tRNA d. snRNA e. mRNA - CORRECT ANSWER d. snRNA The -10 and -35 boxes found in bacterial gene promoters function to: a. recruit DNA polymerase activity for DNA replication before cell division b. activate transcription at the -35 region of a gene c. orient RNA polymerase at a gene's transcription start site d. identify the boundaries between introns and exons e. identify the boundaries for DNA unwinding during transcription - CORRECT ANSWER c. orient RNA polymerase at a gene's transcription start site In mapping a high blood pressure gene in humans, the LOD score is 3.3 for the marker X on chromosome 10. Which of the following is most likely true? a. the high blood pressure gene is located in the short arm of chromosome 10 b. The high blood pressure gene is located in the long arm of chromosome 10 c. The high blood pressure gene is close to the centromere in chromosome 10 d. The high blood pressure gene is likely linked with the marker X e. The high blood pressure gene is likely linked with the marker X near the telomere - CORRECT ANSWER d. The high blood pressure gene is likely linked with the marker X The chromosome of most prokaryotes differs from those of eukaryotes because A. the prokaryotic chromosome is linear, while the eukaryotic is circular. B. the prokaryotic chromosome is circular, while the eukaryotic is linear C. the prokaryotic chromosome is not necessary for survival, while the eukaryotic is. D. the prokaryotic chromosome does not replicate before mitosis, while the eukaryotic does. E. the prokaryotic chromosome does not contain genes, while the eukaryotic does. - CORRECT ANSWER B. the prokaryotic chromosome is circular, while the eukaryotic is linear During chromosome replication, new histone proteins are made during a. G1 and S, and nucleosomes are re-formed using new histones b. S, and nucleosomes are re-formed using old histones c. G1 and S, and nucleosomes are re-formed using new and old histones d. S, and nucleosomes are re-formed using new histones - CORRECT ANSWER c. G1 and S, and nucleosomes are re-formed using new and old histones Loosely aggregated DNA bound to proteins in a eukaryotic cell is called_________; when the cell divides, this condenses into ___________. A. chromatid, nucleus B. chromatin, chromosomes C. chromosomes, chromatin D nucleoid, nucleus - CORRECT ANSWER B. chromatin, chromosomes Which of the following processes does not directly involve DNA? a. Splicing b. Mutations c. DNA repair d. transcription e. Genetic recombination - CORRECT ANSWER a. Splicing In Neurospora, a linear biochemical pathway synthesizes an amino acid Z. E1, E2, and E3 are enzymes that catalyze the three reactions. E1 E2 E3 W------> X --------> Y -------> Z Null mutants for the enzyme E2 gene will grow on minimal medium supplemented with compounds: A) W or X. B) Y or Z only. C) X, Y or Z. D) Z only. E) W only. - CORRECT ANSWER B) Y or Z only. The aminoacyl-tRNAsynthetase enzymes are responsible for: A. adding amino acids to appropriate tRNAs (charging the tRNA). B. regulating the process of amino acid synthesis. C. synthesizing tRNA molecules in the nucleus from rRNA genes. D. catalyzing the enzymatic step of peptide bond formation during translation. E. matching each tRNA with the appropriate mRNA codon. - CORRECT ANSWER A. adding amino acids to appropriate tRNAs (charging the tRNA). In what cellular compartment are introns removed from pre-mRNA to make mature mRNA? A) Cytoplasm B) Endoplasmic Reticulum C) Nucleus D) Mitochondia E) Golgi apparatus - CORRECT ANSWER C) Nucleus Which of the following enzymes is responsible for transcription of the BRCA1 gene in your body? a. RNA Pol V b. RNA Pol IV c. RNA Pol III d. RNA Pol II e. RNA Pol I - CORRECT ANSWER d. RNA Pol II The three bacterial markers a, b, and c are linked, but their order is unknown. A co-transduction experiment is performed and the following results are obtained: - markers a and c are co-transduced at a frequency of 19% - markers a and b are co-transduced at a frequency of 4% - markers c and b are co-transduced at a frequency of 64%. What can be concluded about the arrangement of the three markers on the bacterial chromosome? A. The order is a-b-c, and b is closer to a than to c. B. The order is a-b-c, and b is closer to c than to a. C. The order is b-c-a, and c is closer to a than to b. D. The order is b-a-c, and a is closer to b than to c. E. The order is b-c-a, and c is closer to b than to a. - CORRECT ANSWER E. The order is b-c-a, and c is closer to b than to a. After removal of the RNA primers and replacement with DNA nucleotides, the nick adjacent to Okazaki fragments is filled in through a reaction that involves which enzyme? a. DNA helicase b. SSB protein c. RNA polymerase d. DNA primase e. DNA ligase - CORRECT ANSWER e. DNA ligase Treating the double-strand DNA with sodium bisulfite can cause which of the following mutations? A. A to G B. G to A C. T to C D. C to T E. C to U - CORRECT ANSWER E. C to U Barbara McClintock discovered transposons in 1950s, which led her to win the Nobel prize in 1983. She found spotted kernel colors in maize that is due to effect of Ac/Ds system. Which of the following is not true about the Ac/Ds system in determining kernel colors in maize? A. Normal gene expression of the color gene C results in purple kernels B. Colorless kernels are due to Ac gene jumping out of the C gene. C. Spotted kernels are due to activated transposon jumping out of interrupted C in a few cells during kernel development D. The Ac and Ds genes usually have the same IR sequence - CORRECT ANSWER B. Colorless kernels are due to Ac gene jumping out of the C gene. Based on the wobble hypothesis, the "wobble" base is found: A. at the 5' end of the RNA codon's sense strand. B. at the 3' end of the mRNA codon's antisense strand. C. at the 3' end of the tRNA anticodon. D. at the 5' end of the tRNA anticodon. E. within a tRNA hairpin loop structure. - CORRECT ANSWER D. at the 5' end of the tRNA anticodon. Genetic mutations can be caused by errors during DNA replication. Which of the following pairings usually does not occur? a. Rare enol form of thymine : Normal form of guanine (T*:G) b. Normal thymine : Rare imino form of cytocine (T:C*). c. Rare imino form of cytocine : Normal adenine (C*:A) d. Normal thymine : Rare enol form of guanine (T:G*) e. Normal cytocine : Rare imino form of adenine (C:A*) - CORRECT ANSWER b. Normal thymine : Rare imino form of cytocine (T:C*). We have learned various genetic concepts in class. Which of the following is not true? A. The white flower plant Gregor Mendel found in the 1850s was a forward mutation. B. The genetic screen that Leland Hartwell used in the 1970s can allow him to isolate lethal mutants. C. The approach Francis Collins and Lap-Chee Tsui used to map and clone the Cystic Fibrosis gene in the 1980s can be called a reverse genetics approach D. We can use a reverse genetic approach to understand gene functions in mouse and Arabidopsis. E. Thomas Morgan's research in Drosophila in the 1930s can be called a forward genetics approach - CORRECT ANSWER C. The approach Francis Collins and Lap-Chee Tsui used to map and clone the Cystic Fibrosis gene in the 1980s can be called a reverse genetics approach 40. Two genes A and B is about 5 cM on the human chromosome 2. Which would be the closest estimated for the distance between A and B? a. Approximately 1 Kb b. Approximately 5 Kb c. Approximately 10 Kb d. Approximately 1 Mb e. Approximately 5 Mb - CORRECT ANSWER e. Approximately 5 Mb If a gene contains the following antisense sequence: 5'- ATGCAG-3', what is the mRNA transcript sequence after transcription: a. 5'- AUGCAG-3' b. 5'- CUGCAU-3' c. 5'- GACGUA-3' d. 5'- UACGUC-3' e. None of the above - CORRECT ANSWER b. 5'- CUGCAU-3' We have discussed the molecular mechanism of genetic recombination in class. Which of the following is not true? a. There are structures called Holiday intermediates formed during the process. b. There would be a crossing-over if the resolution of one Holiday intermediate is horizontal and the resolution of the other Holiday intermediate is vertical. c. Genetic recombination starts with a single-strand DNA break on one chromatid. d. There would be a crossing-over if the resolutions of one Holiday intermediates is horizontal and the other is vertical. e. all of the above - CORRECT ANSWER c. Genetic recombination starts with a single-strand DNA break on one chromatid. The double-strand DNA breaks are commonly caused by A. ionizing radiation such as X-rays. B. ultraviolet radiation. C. HCl D. alkylating agents. E. intercalating agents. - CORRECT ANSWER A. ionizing radiation such as X-rays. Mutations in DNA repair genes can lead to cancer. Drs. Tomas Lindahl, Paul Modrich, and Aziz Sanar won the Nobel Prize in Chemistry in 2015 for their mechanistic studies of DNA repair. We discussed their studies in class. Which of the following is not what they studied? a. The base excision DNA repair pathway b. The excision repair system c. The mismatch repair pathway d. The methyl-directed mismatch repair - CORRECT ANSWER d. The methyl-directed mismatch repair We learn ribosome structure in eukaryotes. Roughly how many RNAs and proteins does the human ribosome have? A) 2 rRNA molecules and 2 proteins B) 4 rRNA molecules and 4 proteins C) 4 rRNA molecules and 8 proteins D) 4 rRNA molecules and 32 proteins E) 4 rRNA molecules and 78 proteins - CORRECT ANSWER E) 4 rRNA molecules and 78 proteins An Hfr strain of E. coli with the genotype gly+ aziR StrS is mated with an Fstrain of E. coli of genotype gly aziS StrR .Gly refers to the amino acid glycine, azi refers to sodium azide, and Str refers to the antibiotic streptomycin. Conjugation occurs and the progeny are screened on a selective medium to detect recombinants. If you wanted to select for the F- recombinant genotype gly+ aziR StrR , you should use a minimal medium containing: A. glycine. B. glycine, sodium azide, and streptomycin. C. glycine and streptomycin. D. sodium azide. E. streptomycin and sodium azide. - CORRECT ANSWER E. streptomycin and sodium azide. An E. coli colony grew on minimal medium supplemented with valine and proline. However, bacteria from this colony are unable to grow and form colonies on minimal medium supplemented with valine and threonine. What is the genotype of the bacteria in this E. coli colony? A. val + thr + pro - B. val+ thr - pro+ C. val + thr - pro - D. val - thr - pro - E. val - thr + pro + - CORRECT ANSWER A. val + thr + pro -