Deck 7: Microbial Genetics

Question 1

Which of the following is NOT involved the packaging of eukaryotic chromosomes?

A) nucleosomes
B) Okazaki fragments
C) euchromatin
D) heterochromatin
E) histones

Answer 1

B

Question 2

During , a new peptide bond is formed with the amino acid located in the A site.

A) transcription
B) translation
C) polyadenylation
D) mismatch repair
E) DNA replication

Answer 2

B

Question 3

The AUG codon functions in coding for the amino acid methionine and as a

A) "wobble" codon.
B) recognition site for RNA polymerase.
C) termination signal.
D) marker for introns.
E) start signal.

Answer 3

E

Question 4

Which of the following is found at the 5' end of a DNA strand?

A) a hydrogen bond
B) a methyl group
C) histones
D) a phosphate group
E) a hydroxyl group

Question 5

The process of is described as semiconservative.

A) mismatch repair
B) transformation
C) DNA replication
D) translation
E) transcription

Question 6

The process indicated by the arrow in Figure 7.1 represents

A) lagging strand synthesis.
B) leading strand synthesis.
C) homologous recombination.
D) translation.
E) transcription.

Question 7

The process of requires participation of tRNA molecules.

A) capping
B) DNA replication
C) translation
D) dark repair
E) transcription

Question 8

The events of are initiated at sequences called origins.

A) splicing
B) DNA replication
C) transcription
D) transposition
E) translation

Question 9

If the codon AAA is changed to AAG, it still codes for the amino acid lysine; this is an example of a

A) frameshift mutation.
B) silent mutation.
C) missense mutation.
D) nonsense mutation.
E) dimer formation.

Question 10

Which of the following processes is involved in the "central dogma" of genetics?

A) translation only
B) transcription and translation
C) DNA replication and translation
D) DNA replication only
E) transcription only

Question 11

Which of the following is NOT a characteristic of Okazaki fragments?

A) They are checked for accuracy by DNA polymerase III.
B) They are joined together by DNA ligase.
C) They make up the lagging strand of replicated DNA.
D) They are longer in eukaryotic cells.
E) They begin with an RNA primer.

Question 12

Which of the following statements is true of bacterial plasmids?

A) They are small circular DNA molecules.
B) They can replicate autonomously.
C) They carry genes for essential metabolic functions.
D) They are always found in the nucleoid.
E) They are small circular DNA molecules that can replicate autonomously.

Question 13

Genetic elements known as promoters are initiation points in the process of

A) transcription.
B) mutation repair.
C) DNA replication.
D) translation.
E) transformation.

Question 14

Typical eukaryotic genomes are composed of DNA molecule(s).

A) multiple circular
B) multiple linear
C) a single linear
D) a single circular
E) both linear and circular

Question 15

A codon is a particular combination of three nucleotides. Therefore, there are possible combinations of the nucleotides A, C, G, and T.

A) 4
B) 16
C) 64
D) 32
E) 12

Question 16

Another term for the palindromic sequence found at the ends of transposons is a(n)

A) bacteriophage.
B) transposase.
C) complex transposon.
D) inverted repeat.
E) insertion sequence.

Question 17

Which of the following is NOT involved in the regulation of the lac operon?

A) glucose
B) cyclic AMP
C) an inducer
D) a repressor protein
E) an iRNA

Question 18

Which of the following is characteristic of prokaryotic genomes but NOT eukaryotic genomes?

A) enclosed in a nuclear membrane
B) typically consist of a few to several chromosomes
C) circular chromosomes
D) histones
E) linear chromosomes

Question 19

All of the following are associated with nucleic acid structure EXCEPT

A) ionic bonds.
B) ribose.
C) uracil.
D) phosphate.
E) hydrogen bonds.

Question 20

Frederick Griffith discovered

A) transformation.
B) conjugation.
C) transposons.
D) DNA.
E) the lac operon.

Question 21

RNA polymerase is primarily responsible for

A) polyadenylation.
B) transformation.
C) translation.
D) transcription.
E) DNA replication.

Question 22

The process known as is initiated with the incorporation of fMet.

A) translation
B) capping
C) DNA replication
D) light repair
E) transcription

Question 23

Which of the following causes mutations by creating thymine dimers?

A) nucleotide analogs
B) nitrous acid
C) benzopyrene
D) gamma rays
E) ultraviolet light

Question 24

The process of requires the activity of DNA ligase.

A) translation
B) capping
C) DNA replication
D) transduction
E) transcription

Question 25

Which of the following types of plasmids allows a bacterial cell to kill its competitors?

A) bacteriocin factors
B) fertility factors
C) cryptic plasmids
D) virulence factors
E) resistance factors

Question 26

A wild- type organism and a genetic variant both have a gene encoding a receptor producing a chemotactic response to metabolite A. The genetic variant has a mutation in a regulatory gene for expression of the receptor. Which of the following statements with respect to the receptor is CORRECT?

A) The organisms have the same receptor genotype but different phenotypes.
B) The phenotypes of both organisms are the same, but the genotypes differ.
C) The genotypes and phenotypes of both organisms are the same.
D) The organisms have different genetic sequences for the receptor.
E) The answer cannot be determined from the information provided.

Question 27

Which of the following is a characteristic shared by DNA and RNA polymerases?

A) dependence on helicase
B) efficiency of proofreading
C) speed
D) direction of polymerization
E) type of nucleotides used

Question 28

Which of the following is a DNA repair enzyme activated by visible light?

A) DNA ligase
B) primase
C) DNA photolyase
D) bacteriocin
E) transposase

Question 29

Which of the following statements concerning transcription in bacteria is FALSE?

A) There are a variety of sigma factors that affect transcription.
B) The same RNA polymerase transcribes primer RNA, mRNA, tRNA, and rRNA.
C) It occurs in the nucleoid region.
D) Termination is either self- induced or due to the presence of Rho protein.
E) Sigma factors are parts of RNA polymerase that recognize promoter regions.

Question 30

Inducible operons

A) usually require an activator to be transcribed.
B) are generally anabolic pathways.
C) are normally active.
D) are active in the presence of a repressor.
E) usually require a repressor to be transcribed.

Question 31

During elongation a charged tRNA first enters the ribosomal site and then moves into the site.

A) A, P
B) P, E
C) E, A
D) A, E
E) P, A

Question 32

Semiconservative DNA replication means that

A) nucleotides are constantly being recycled as cells make DNA.
B) each daughter DNA molecule is composed of one original strand and one new strand.
C) each strand of a double- stranded DNA molecule is replicated differently.
D) the cell can proofread its newly synthesized DNA only part of the time.
E) the sequence of a DNA molecule is preserved as it is being replicated.

Question 33

The horizontal transfer process known as transduction

A) involves a mutagen.
B) involves a virus.
C) requires a pilus.
D) requires a cell to be "competent."
E) requires a plasmid.

Question 34

Codons are recognized during

A) transduction.
B) translation.
C) transcription.
D) DNA replication.
E) base excision.

Question 35

Which of the following are considered to be frameshift mutations?

A) inversions only
B) insertions only
C) deletions only
D) both inversion and insertions
E) both deletions and insertions

Question 36

The procedure known as "replica plating" is used in

A) the Ames test.
B) mutagenesis.
C) negative selection only.
D) both positive and negative selection.
E) positive selection only.

Question 37

Which of the following is involved in translation?

A) mRNA only
B) rRNA only
C) tRNA only
D) both mRNA and tRNA
E) mRNA, rRNA, and tRNA are all involved.

Question 38

Which of the following regulatory RNAs alter translation in response to environmental conditions?

A) riboswitches
B) transfer RNAs
C) miRNA- induced silencing complexes (miRISCs)
D) microRNAs
E) small interfering RNAs

Question 39

In conjugation, F+ cells

A) can transfer DNA only to other F+ cells.
B) contain "jumping genes."
C) serve as recipient cells.
D) do not have conjugation pili.
E) contain an F plasmid.

Question 40

The DNA sequence of a portion of gene in a wild- type organism is TTACCATATTCACCC, and the corresponding peptide sequence is Leu- Pro- Tyr- Ser- Pro. The corresponding gene fragment in phenotypic variant of the organism is TTACCATATTCACCC and the peptide sequence is Leu- Pro- Cys- Ser- Pro. This is an example of a mutation (type) resulting in a mutation (effect).

A) base substitution; silent
B) insertion; nonsense
C) deletion; missense
D) base substitution; nonsense
E) base substitution; missense

Question 41

RNA polymerase initiates transcription by recognizing specific DNA sequences called (promoter/origins/operons).

Question 42

The phenotype of an organism is its set of (genes/traits/chromosomes).

Question 43

Except during initiation of translation, transfer RNA molecules carrying amino acids initially bind to the ribosome at the (P/A/E) site.

Question 44

Loosely packed, transcriptionally active regions of a eukaryotic chromosome are called (euchromatin/heterochromatin/nucleosomes).

Question 45

A(n) (genome/codon/operon) is a set of prokaryotic genes that are regulated and transcribed as a unit.

Question 46

A protein has altered function as a result of a single amino acid substitution in the polypeptide. This change resulted from a (missense/nonsense/silent) mutation.

Question 47

A(n) (operon/codon/gene) is a specific sequence of nucleotides that codes for a protein or an RNA molecule.

Question 48

While studying a bacterial strain a scientist notes a short DNA sequence between inverted repeats is present in both the chromosome and a plasmid within the cell. This sequence is most likely a(n) (phage/transposon/F plasmid).

Question 49

The chemical 5- bromouracil mimics the chemical structure of thymine, making it a(n) (analog/nucleotide/precursor) of thymine.

Question 50

The bacterial chromosome is

A) found in a nucleoid.
B) found in a nucleus.
C) usually circular.
D) both circular and found in a nucleoid.
E) both circular and found in a nucleus.

Question 51

The (leading/lagging/replicating) strand is the DNA strand that is synthesized continuously during DNA replication.

Question 52

The Ames test demonstrates that a chemical is

A) carcinogenic.
B) mutagenic in humans.
C) carcinogenic in Salmonella.
D) mutagenic in Salmonella.
E) carcinogenic in humans.

Question 53

The enzyme responsible for separating the DNA strands during DNA replication is (topoisomerase/primase/helicase).

Question 54

Transfer of random pieces of DNA mediated by phage is known as

A) specialized transduction.
B) transposition
C) conjugation
D) transformation of competent cells.
E) generalized transduction

Question 55

Acridine dyes distort the structure of DNA causing (frameshift/missense/nonsense) mutations in gene sequences. (Answer in terms of the effect on gene function.)

Question 56

DNA replication and RNA transcription have many features in common. Which of the following does NOT occur in both processes?

A) a requirement for a primer
B) base- pairing of complementary nucleotides
C) separation of the DNA strands ("unzipping")
D) energy to drive the process is provided by triphosphate nucleotides
E) directionality of synthesis

Question 57

DNA damage caused by ethidium bromide results in mutations.

A) substitution
B) insertion
C) deletion
D) both inversion and insertion
E) both insertion and deletion

Question 58

The (codon/antidcodon/loop) of a transfer RNA molecule is complementary to a codon in a messenger RNA molecule.

Question 59

The (phenotype/genome/genotype) is the set of genes in the genome of an organism.

Question 60

Transfer of DNA between bacterial cells by viruses is called (transformation/transduction/conjugation).

Question 61

A point mutation can be completely harmless, or it can result in the death of a cell or organism. Explain why these types of mutations can have such varying effects.

Question 62

Prokaryotic cells are diploid.

Question 63

DNA, which is negatively charged, wraps around positively charged histones as part of the packaging of eukaryotic chromosomes.

Question 64

The structure of DNA explains both its ability to encode genetic information and the way in which it is copied during cell reproduction.

Question 65

Most bacteria have a natural ability to take up DNA from their environment.

Question 66

The phenotype of an organism reflects only part of its genotype.

Question 67

Pyrimidine dimers are severe mutations because cells have few mechanisms for repairing them.

Question 68

Bidirectional replication means that each strand of a DNA molecule is replicated in the opposite direction from the other.

Question 69

A chemical is reported to inhibit bacterial replication. Bacterial cells are placed in medium with all nutrients necessary for replication. The chemical is added to the culture, and after a half hour an extract of the DNA is prepared. A significant percentage of the DNA is in pieces about 1000 to 2000 bases in length. The results are consistent with the chemical blocking the function of DNA ligase.

Question 70

Describe the basic similarities and differences between DNA replication and transcription.

Question 71

Bacterial strain A contains a plasmid. Bacterial strain B does not. When the bacteria are incubated together in a broth culture strain B cells containing the plasmid can be isolated. Devise an experiment to determine what type of gene transfer process is involved.

Question 72

DNA polymerase III participates in the dark repair mechanism of DNA mutation repair.

Question 73

Compare and contrast the lactose operon with the tryptophan operon.

Question 74

Describe the various types of nucleic acids that are typically found in cells.

Question 75

In generalized transduction, viruses carry random DNA sequences from one cell to another.