exam 2 study guide Flashcards
(29 cards)
Which one of the following sequences best describes the flow of information from a gene to synthesis of a cellular component? A) RNA → DNA → RNA → protein B) DNA → RNA → protein C) DNA → amino acid → RNA → protein D) DNA → tRNA → mRNA → protein E) protein → RNA → DNA
B) DNA → RNA → protein
The sugar-phosphate backbone of DNA is held together by \_\_\_\_\_\_\_ bonds and the two strands of a double helix are held together by \_\_\_\_\_ bonds. A) hydrogen, ionic B) covalent, ionic C) covalent, hydrogen D) covalent, covalent E) hydrogen, covalent
C) covalent, hydrogen
Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. What percent of the nucleotides in this sample will be thymine?
A) 12 B) 24 C) 31 D) 38
E) It cannot be determined from the information provided.
A) 12
What is the role of DNA gyrase in DNA replication?
A) join Okazaki fragments together
B) stabilize the unwound parental DNA
C) unwind the parental double helix
D) relieves tension in the DNA ahead of the replication fork
E) synthesize RNA nucleotides to make a primer
D) relieves tension in the DNA ahead of the replication fork
Where would you find an anticodon?
A) tRNA B) mRNA C) rRNA D) cDNA E) DNA
A) tRNA
A base change in a gene’s promoter may affect
A) the amino acid sequence of the protein
B) the ability to form a translation initiation complex
C) the binding of RNA polymerase
D) the formation of a replication fork
E) your future earnings potential
C) the binding of RNA polymerase
What is the purpose of an operator in the process of transcription?
A) binding region for RNA polymerase
B) binds to the promoter to prevent transcription
C) induces translation in the presence of substrate
D) controls transcription through repressor binding
E) contains the genetic code for the repressor protein
D) controls transcription through repressor binding
Which of the following does not contain amino acids?
A) repressors B) polymerases
C) promoters D) helicases
C) promoters
Why does transcription and translation occur simultaneously in prokaryotes but not in eukaryotes?
A) introns must be removed from eukaryotic transcripts before
translation can occur.
B) eukaryotic cells are much larger than prokaryotes
C) prokaryotes lack nuclear membranes
D) eukaryotes have ribosomes in the nucleus
E) A and C
F) A, B, and C
G) A, B, C, and D
E) A and C
Synthesis of a repressible enzyme is stopped by
A. The allosteric inhibitor.
B. The corepressor-repressor binding to the operator.
C. The substrate binding to the repressor.
D. The corepressor binding to the operator.
E. The end-product binding to the promoter.
B. The corepressor-repressor binding to the operator.
An operon that is activated in response to the presence of a substrate is called A. A constitutive operon. B. An inducible operon. C. A feedback operon. D. A catabolic operon. E. A repressible operon.
B. An inducible operon.
Which of the following statements about Catabolite repression is false?
A. When glucose is present cAMP levels are high.
B. In the presence of lactose and glucose, the lac repressor cannot bind.
C. When cAMP levels are low, CRP cannot bind to the CAP site.
D. cAMP binds to the CAP protein.
E. The amount of lactose present has no affect on cAMP levels.
A. When glucose is present cAMP levels are high.
Synthesis of a constitutive enzyme is stopped by
A. The substrate binding to the repressor.
B. The end-product binding to the promoter.
C. The corepressor binding to the operator.
D. The corepressor-repressor binding to the operator.
E. None of the above.
E. None of the above.
Conjugation is
A) transfer of genetic material by bacteriophage
B) transfer of genetic material involving a sex pilus
C) the uptake of naked DNA into a cell
D) how transposons move from plasmid to chromosome
E) a procedure used in sex change operations
B) transfer of genetic material involving a sex pilus
A \_\_\_\_\_\_\_ mutation results in a new amino acid. A \_\_\_\_\_\_\_ mutation does not change the amino acid sequence. A \_\_\_\_\_\_\_ mutation results in a stop codon. A. Silent, nonsense, missense B. Nonsense, silent, missense C. Silent, missense, nonsense D. Missense, nonsense, silent E. Nonsense, missense, silent F. Missense, silent, nonsense
F. Missense, silent, nonsense
The major effect of (nonionizing) UV radiation on a cell is that it causes
A. Methylation of DNA
B. DNA to break.
C. Bonding between adjacent nucleotides.
D. Base substitutions.
E. activation of transposases.
C. Bonding between adjacent nucleotides.
A base substitution mutation in a gene sometimes does not result in a different amino acid. Which of the following factors could account for this?
A) some amino acids are produced from more than one codon
B) the mutation affects the protein but not the amino acids
C) the mutation affects only the DNA sequence, so the amino acids are unchanged
D) the mutation may be corrected during translation
E) trick question- the amino acid is always changed
A) some amino acids are produced from more than one codon
Enzymes that are used to cut DNA at specific sites are known as A. exonucleases B. proteases C. restriction enzymes D. ligases E. polymerases
C. restriction enzymes
Antibiotic resistance genes are useful in gene cloning because
A. they code for antibiotics
B. they kill pathogenic bacteria
C. they enable normal flora to thrive
D. they protect us from infections
E. they allow us to select host cells that contain
plasmids
E. they allow us to select host cells that contain plasmids
Restriction fragment length polymorphisms
A. are used in constructing recombinant plasmids.
B. are necessary parts of plasmids.
C. are necessary for polymerase chain reaction.
D. result from differences in the nucleotide
sequences of DNA samples.
E. are created by recombinant DNA technology
D. result from differences in the nucleotide sequences of DNA samples.
. Which of the following is not associated with DNA fingerprinting?
A. nucleic acid sequencing
B. Gel electrophoresis.
C. Use of a radiolabeled DNA probe
D. Restriction enzyme digestion.
E. Comparison of DNA restriction fragments.
A. nucleic acid sequencing
Which of the following is not a characteristic of E. coli that makes it a good host for producing recombinant proteins? A. it is easy to grow. B. its genetics is well known. C. it can remove introns. D. it grows rapidly. E. it is economical.
C. it can remove introns.
Which of the following processes produces multiple copies of a region of DNA? A. DNA fingerprinting. B. transformation. C. Polymerase Chain Reaction D. RFLPs E. Southern blotting
C. Polymerase Chain Reaction
A drug which inhibits RNA replication would be most
effective on (inappropriate question for unit 2 since it requires some knowledge of viruses.)
A. fungi
B. RNA viruses
C. protozoa
D. DNA viruses
E. none of the above- this drug would kill our cells.
B. RNA viruses
