Deck 7: Microbial Genetics

Question 1

What is notable about the microbe Carsonella ruddii?

A) It is the only prokaryote that has a true nucleus.
B) It is the only prokaryote with a linear chromosome.
C) It is a diploid prokaryote.
D) It has no DNA.
E) It has the smallest known cellular genome.

Answer 1

E

Question 2

RNA polymerase and DNA polymerase differ from each other in all of the following ways EXCEPT:

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

Answer 2

D

Question 3

DNA ligase

A) synthesizes short DNA molecules important for the function of DNA polymerase.
B) breaks hydrogen bonds between complementary nucleotides.
C) seals gaps between DNA fragments.
D) proofreads DNA molecules.
E) assists in recognition of promoters during transcription.

Answer 3

C

Question 4

All of the following are associated with the packaging of eukaryotic chromosomes EXCEPT:

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

Question 5

Which of the following is the strongest base pair?

A) adenine- uracil
B) adenine- guanine
C) adenine- thymine
D) cytosine- thymine
E) guanine- cytosine

Question 6

All of the following are associated with nucleic acid structure EXCEPT:

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

Question 7

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

A) transcription
B) translation
C) DNA replication
D) Both A and B are correct.
E) A, B, and C are correct.

Question 8

All of the following are characteristics of Okazaki fragments EXCEPT:

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

Question 9

Semiconservative DNA replication means that

A) the sequence of a DNA molecule is preserved as it is being replicated.
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) nucleotides are constantly being recycled as cells make DNA.
E) the cell can proofread its newly synthesized DNA part of the time.

Question 10

All of the following are true statements concenrning plasmids EXCEPT:

A) They can replicate autonomously.
B) They are small circular molecules of DNA.
C) They carry genes that are required for growth and repair.
D) They can be found in bacteria, fungi, and protozoa.
E) They can carry genes that confer resistance against antibiotics.

Question 11

All of the following statements concerning transcription in bacteria are true EXCEPT:

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

Question 12

All of the following are true statements concerning eukaryotic transcription EXCEPT:

A) Multiple elongation factors are required.
B) A guanine is added to the 3' end and a poly A tail is added to the 5' end.
C) There are four different RNA polymerases.
D) Multiple transcription factors are required.
E) Transcription occurs in the nucleus, mitochondria, and in chloroplasts (if present).

Question 13

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

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

Question 14

Because of proofreading, what is the error rate associated with DNA replication?

A) 1 error in 1,000 bases
B) 1 error in 1 million bases
C) 1 error in 100,000 bases
D) 1 error in 1 billion bases
E) 1 error in 10 million bases

Question 15

Which of the following is involved in translation?

A) tRNA
B) mRNA
C) rRNA
D) Both A and C are correct.
E) A, B, and C are correct.

Question 16

Which of the following is found at the 3' end of a DNA strand?

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

Question 17

Which of the following types of plasmids carry genes that protect bacteria from various antimicrobial drugs?

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

Question 18

In addition to coding for the amino acid methionine, what function does the codon AUG serve?

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

Question 19

Which of the following must be removed from an mRNA molecule before it can be translated in eukaryotes?

A) introns
B) codons
C) promoters
D) exons
E) anticodons

Question 20

During translation, an mRNA codon will pass through which of the following sequences of tRNA binding sites on the ribosome?

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

Question 21

Why is Taq polymerase used in PCR?

A) It resists the high temperatures of PCR better than other polymerases.
B) It can unwind DNA from associated histones.
C) It makes DNA more quickly than other types of polymerases.
D) It makes fewer mistakes than other types of polymerases.
E) It corrects frameshift mutations as it replicates DNA.

Question 22

Which of the following is classified as a frameshift mutagen?

A) acridine
B) ethidium bromide
C) benzopyrene
D) Both A and B are correct.
E) A, B, and C are correct.

Question 23

In conjugation, F+cells

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

Question 24

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

Question 25

If the codon AAA is changed to UAA, it no longer codes for an amino acid; instead, it becomes a stop codon that signals translation termination in a protein. This is an example of a

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

Question 26

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

Question 27

How does short interference RNA (siRNA) work?

A) It binds to a repressor protein, which in turn inactivates a gene.
B) It converts heterochromatin to euchromatin.
C) It binds to ribosomes and prevents tRNA molecules from attaching.
D) It binds to and inactivates a target nucleic acid sequence.
E) It creates frameshift mutations that produce nonfunctional versions of proteins.

Question 28

All of the following are characteristics of inducible operons EXCEPT:

A) they are often involved in anabolic pathways.
B) they are a way for bacterial cells to conserve energy.
C) they are active in the presence of an inducer.
D) they are normally inactive.
E) they involve a repressor.

Question 29

The energy required for DNA replication comes from:

A) triphosphate deoxyribonucleotides.
B) RNA primer.
C) DNA ligase.
D) DNA polymerase.
E) the leading strand.

Question 30

Horizontal gene transfer

A) typically is a rare event.
B) involves the transfer of DNA from a donor cell to a recipient cell.
C) occurs only between cells of the same species.
D) Both A and B are correct.
E) A, B, and C are correct.

Question 31

Genes are active in a region of the eukaryotic chromosome called

A) euchromatin.
B) heterochromatin.
C) the nucleoid.
D) the plasmid.
E) the histone.

Question 32

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

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

Question 33

Prokaryotic cells are diploid.

Question 34

The Ames test proves that a chemical is

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

Question 35

Nitrous acid causes which of the following types of mutations in a cell?

A) base- pair substitutions
B) frameshifts
C) chromosome breaks
D) base- pair deletions
E) pyrimidine dimers

Question 36

Prokaryotes have multiple types of DNA polymerase.

Question 37

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

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

Question 38

In the process of transformation,

A) cells lose part of their DNA and enter a dormant state.
B) DNA "jumps" from one location in the genome to another.
C) cells take up DNA from their environment.
D) DNA is transferred from one cell to another by a virus.
E) DNA is transferred between cells via a pilus.

Question 39

The most common type of mutation is a point mutation.

Question 40

Which of the following are considered frameshift mutations?

A) deletions
B) inversions
C) insertions
D) Both A and B are correct.
E) Both A and C are correct.

Question 41

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

Question 42

A(n) is a mutant organism that has different nutritional requirements than the original wild- type organism.

Question 43

If the codon AUG, coding for methionine, were mutated to AAG, coding for lysine, this would be an example of a(n) mutation.

Question 44

RNA polymerase initiates transcription by recognizing specific nucleotide sequences called .

Question 45

RNA molecules contain both introns and exons.

Question 46

Tightly packed regions of a eukaryotic chromosome are called .

Question 47

The is the DNA strand that is synthesized continuously during DNA replication.

Question 48

"Jumping genes" that can move from one location to another in an organism's genome are called .

Question 49

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

Question 50

Cells that are able to perform transformation are said to be .

Question 51

dATP and dCTP are examples of _, the building blocks of DNA molecules.

Question 52

5'- bromouracil mimics the chemical structure of thymine, making it a(n) _.

Question 53

The of a transfer RNA molecule is complementary to a codon in a messenger RNA molecule.

Question 54

The SOS response is a DNA repair mechanism that responds to extreme DNA damage.

Question 55

During translation, the growing polypeptide is positioned in the of the ribosome.

Question 56

The term refers to the physical features and traits of an organism.

Question 57

The point at which a DNA double helix is "unzipped" is the .

Question 58

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

Question 59

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

Question 60

Positive selection methods work by eliminating cells with wild- type phenotypes, leaving only mutants.

Question 61

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

Question 62

Compare and contrast the lactose operon with the tryptophan operon.

Question 63

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 64

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

Question 65

How does DNA directly and indirectly control all the activities of a cell?