Bio 225 Chapter 8 Practice Questions
1. The physical characteristics of an organism make up the organism’s:
A. Genotype
B. Phenotype
2. An organism detoxifies H2O2. This statement describes the organism’s:
A. Genotype
B. Phenotype
3. An organism has a gene that codes for catalase. This statement describes the organism’s:
A. Genotype
B. Phenotype
4. What is a gene?
A. A messenger RNA molecule
B. A collection of codons
C. A segment of DNA with a specific nucleotide sequence
D. A segment of DNA that codes for a specific product
5. Which of the following incorrectly describes a DNA molecule?
A. Helical
B. Antiparallel
C. Single stranded
D. Contains the nucleotides A, G, T, and C
6. If strands of DNA are said to be antiparallel then they are:
A. Perpendicular
B. Complementary
C. Identical
D. Oriented in opposite directions
7. The antisense strand of DNA is:
A. Identical to the sense strand
B. The strand that codes for a product
C. Complementary to the mRNA
D. Identical to the mRNA (except for having T where the mRNA has U)
8. Prokaryotic and eukaryotic chromosomes are different in that:
A. Prokaryotic chromosomes are single stranded
B. Eukaryotic chromosomes lack introns
C. Prokaryotic chromosomes are circular
D. Prokaryotic chromosomes consist of chromosomal RNA (cRNA)
9. The DNA strand in the diagram has two ends, labeled A and B. The end labeled A is the 5’
end.
A. True
B. False
10. DNA replication uses:
A. DNA-directed DNA polymerase
B. DNA-directed RNA polymerase
C. RNA-directed DNA polymerase
D. Ribosomes
E. mRNA
F. tRNA
11. In the diagram above, which RNA primer (A or B) is the starting point for the leading strand?
A. RNA primer A
B. RNA primer B
C. Can’t tell
12. In the diagram above, which RNA primer (A or B) is the starting point for the discontinuous
strand?
A. RNA primer A
B. RNA primer B
C. Can’t tell
13. In the diagram above, which RNA primer (A or B) is the starting point for the sense strand?
A. RNA primer A
B. RNA primer B
C. Can’t tell
14. In prokaryotes, two replication forks arise at the origin of replication and move in opposite
directions until:
A. They reach the ends of the chromosome
B. They meet
C. They reach the stop codon
D. Prokaryotes only have one replication fork
15. In transcription:
A. DNA-directed RNA polymerase makes tRNA
B. DNA-directed DNA polymerase replicates DNA
C. Ribosomes make tRNA
D. Ribosomes make amino acids
E. Ribosomes read mRNA and make protein
F. DNA-directed RNA polymerase makes mRNA
16. In translation:
A. DNA-directed RNA polymerase makes tRNA
B. DNA-directed DNA polymerase replicates DNA
C. Ribosomes make tRNA
D. Ribosomes make amino acids
E. Ribosomes read mRNA and make protein
F. DNA-directed RNA polymerase makes mRNA
17. In the diagram above, the partial strand labeled A. would be part of the:
A. DNA sense strand
B. DNA anti-sense strand
C. mRNA
D. tRNA
18. In the diagram above, the strand labeled B. would be part of the:
A. DNA sense strand
B. DNA anti-sense strand
C. mRNA
D. tRNA
19. In the diagram above, the strand labeled C. would be part of the:
A. DNA sense strand
B. DNA anti-sense strand
C. mRNA
D. tRNA
20. In the diagram above, the strand labeled D. would be part of the:
A. DNA sense strand
B. DNA anti-sense strand
C. mRNA
D. tRNA
21. In the diagram above, the three nucleotides in the shaded box labeled G. are a/an:
A. Codon
B. Anticodon
C. Triplet
D. Gene
22. In the diagram above, the three nucleotides in the shaded box labeled H. are a/an:
A. Codon
B. Anticodon
C. Triplet
D. Gene
23. In the diagram above, the three nucleotides in the shaded box labeled F. are a/an:
A. Codon
B. Anticodon
C. Triplet
D. Gene
Use this table for questions 24 and 25.
24. If the sequence of the DNA template strand is 5’TACTCATGGGTGTTGCATACT3’ the
sequence of the resulting protein is:
A. Met-Ser-Thr-His-Asn-Val
B. Tyr-Ser-Ser-Val-Phe-His-Thr
C. Ser-Tyr-Val-Val-Gly-Thr-Leu
D. Ser-Met-Gln-His-Pro-Val
E. Met-Gln-His-Pro
F. None of the above
25. If a point mutation changes the sequence in the last question to
5’TACTCATGGGTGTTACATACT3’ the sequence of the resulting protein is:
A. Met-Ser-Thr-His-Asn-Val
B. Ser-Met-Gln-His-Pro-Val
C. Tyr-Ser-Ser-Val-Leu-His-Thr
D. Ser-Tyr-Ile-Val-Gly-Thr-Leu
E. Transcription would stop after the second amino acid
F. Translation would terminate immediately after the start codon
G. None of the above
26. Ribosomes are used for:
A. Transcription
B. Translation
C. DNA replication
D. mRNA synthesis
27. DNA-directed RNA polymerase makes:
A. Ribosomes
B. tRNA
C. mRNA
D. Protein
E. Daughter DNA
28. An inducible enzyme:
A. Represses the induction of enzymes to metabolize a less desirable substrate
B. Is released from allosteric inhibition by the presence of product
C. Requires a co-repressor to function
D. Functions as a co-repressor
E. Is synthesized when the repressor is inhibited by the substrate
29. A repressible enzyme:
A. Is synthesized when the substrate binds to the repressor
B. Is not synthesized when the end product binds to the operator
C. Is inhibited by the co-repressor binding to the allosteric site
D. Is not synthesized when the end product binds to the repressor
30. Synthesis of enzymes coded for by genes that are part of the lac operon:
A. Is inhibited by galactose
B. Is not turned on unless lactose is present
C. Requires a co-repressor
D. Is stimulated by binding of glucose to the repressor
E. Is inhibited by lactose binding to the repressor
31. Synthesis of enzymes coded for by genes that are part of the trp operon:
A. Is turned on by the presence of tryptophan
B. Is stimulated by inhibition of the repressor
C. Is usually turned off
D. Is inhibited when the repressor binds to the promoter
E. Is inhibited when the co-repressor and the repressor bind to the operator
32. Mutations are changes in the base sequence of a DNA molecule.
A. True
B. False
33. Mutations are always harmful to an organism.
A. True
B. False
34. A frameshift mutation is the result of:
A. The substitution of one base for another
B. The addition or deletion of a base or bases to a strand of DNA
C. The deletion of the promoter
D. The deletion of the operator
E. Transposition of the promoter and operator
35. A point (single base pair) mutation will change the product coded for by the gene in which
the mutation occurs.
A. True
B. False
C. Not necessarily
36. A frameshift mutation will change the product coded for by the gene in which the mutation
occurs.
A. True
B. False
C. Not necessarily
37. An example of a result of mutation is:
A. An organism loses the ability to synthesize an amino acid and must acquired it from
elsewhere
B. An organism gains the ability to synthesize an amino acid and no longer needs to acquire
it from elsewhere
C. All of the above
D. None of the above
38. Mutations may be caused by:
A. Chemicals
B. Ionizing radiation
C. Non-ionizing radiation
D. Spontaneous changes in the base sequence without mutagens
E. All of the above
F. a and b only
G. None of the above
39. Tests that identify mutant cells:
A. Disregard phenotype and test for altered genotype
B. Use positive selection techniques to select non-mutated cells and reject mutated cells
C. Use replica plating to detect the presence of mutant cells that have gained new metabolic
capabilities
D. May detect mutants that have either gained or lost metabolic capabilities
40. The Ames test:
A. Uses replica plating to identify histidine auxotrophs of Salmonella
B. Tests the ability of chemicals to cause Salmonella to lose the ability to synthesize
histidine
C. Tests for the ability of mutant liver enzymes to cause mutations in Salmonella
D. Uses back mutation (reversion) of Salmonella auxotrophs exposed to chemicals as a
measure of carcinogenicity
41. Genetic recombination:
A. Is the rearrangement of genes from separate groups of genes
B. Usually involves DNA from different organisms
C. Can occur when DNA is passed horizontally
D. Includes crossing over
E. All of the above
42. The process by which two chromosomes come in contact and exchange genetic material is:
A. Transformation
B. Transduction
C. Conjugation
D. Crossing over
43. The process by which genetic material is passed from one cell to another through a sex pilus
is:
A. Transformation
B. Transduction
C. Conjugation
D. Crossing over
44. The process by which a cell takes up naked pieces of DNA in solution is:
A. Transformation
B. Transduction
C. Conjugation
D. Crossing over
45. The process by which genetic material is passed from one cell to another by a virus is:
A. Transformation
B. Transduction
C. Conjugation
D. Crossing over
46. A small piece of DNA that can move from one location in a chromosome to another is:
A. An operon
B. A plasmid
C. A transposon
D. A bacteriophage
E. A promoter
47. A small, circular, self-replicating, extra-chromosomal piece of DNA is:
A. An operon
B. A plasmid
C. A transposon
D. A bacteriophage
E. A promoter
Key
Bio 225 Chapter 8 Practice Questions
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
b
b
a
d
c
d
c
c
a
a
a
b
c
b
f
e
a
b
c
d
a
b
c
e
25
f
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
b
c
e
d
b
e
a
b
b
c
a
c
e
d
d
e
d
c
a
b
c
b
But how about B as well?
Very Good! If you just guessed your way to this answer here is a hint: The RNA polymerase
reads the DNA template strand from 3' to 5' so the mRNA will be synthesized (transcription
occurs) 5' to 3'; the ribosome reads the mRNA 5’ to 3’, starts translation at the start codon and
ends at the stop codon.
Even better! Unless you guessed, in which case use the hint in the previous question's correct
answer to understand this answer. Note – I just changed the word transcription to translation in
answer choice F – when choice F said “transcription would terminate immediately after the start
codon” the correct answer would have been G (none of the above) because transcription would
continue until RNA polymerase reached the termination of transcription site in the gene, the
ribosome recognizes the stop codon during translation and that’s where the mutation would have
its effect.