Deck 17: Bacterial and Viral Genetics

Question 1

Genetic recombination ____.

A) occurs in eukaryotes, but not prokaryotes
B) involves exchange between non-homologous regions of DNA
C) results from asexual reproduction
D) decreases genetic diversity
E) can occur in the absence of meiosis

Answer 1

E

Question 2

Cultures of genetically identical cells are called ____.

A) bacteriophages
B) clones
C) prophages
D) prions
E) auxotrophs

Answer 2

B

Question 3

Escherichia coli bacteria ____.

A) has only recently been employed in scientific research
B) can undergo natural transformation
C) is a disease caused by prions
D) replicates slowly
E) can be infected by bacteriophages

Answer 3

E

Question 4

The results of Lederberg and Tatum's experiments with E. coli auxotrophs indicated that ____.

A) bacteria can be transformed when free DNA is available in their environment
B) bacteria are able to exchange genetic material with eukaryotic organisms
C) bacteria reproduce by sexual rather than asexual reproduction
D) genetic recombination can occur in bacteria
E) genetic recombination does not occur in bacteria since they do not undergo meiosis

Question 5

Small circles of DNA that occur in bacteria in addition to the main circular chromosomal DNA molecule are called ____.

A) transformants
B) plastids
C) plasmids
D) plasmitrons
E) bacteriophages

Question 6

Ammonium chloride, a commonly used salt in minimal medium, ____.

A) is an organic carbon source
B) provides nitrogen
C) jellifies the medium
D) liquefies the medium
E) sterilizes the medium

Question 7

F⁺cells ____.

A) are able to conjugate with donor cells
B) are able to conjugate with recipient cells
C) are able to conjugate with other F⁺cells
D) receive DNA during conjugation
E) are infected with a virus

Question 8

The ability to conjugate depends on the presence of a plasmid called the ____ within the donor cell.

A) X factor
B) F factor
C) C factor
D) sex pilus
E) S factor

Question 9

How do the constituents of liquid medium differ from solid, gel-like medium?

A) Liquid medium contains agar, a polysaccharide extracted from algae.
B) Solid medium contains agar, a polysaccharide extracted from algae.
C) Solid medium contains agar, a complex lipid extracted from bacterial membranes.
D) Liquid medium contains more salts, which lower the freezing point.
E) Solid medium contains more fatty acids, which raise the melting point.

Question 10

Auxotrophs ____.

A) are nutritional-requirement mutants
B) can grow on minimal media
C) feed on proteins
D) make their own nutrients
E) produce antibiotics

Question 11

During bacterial conjugation, bacteria use a long tubular structure called a(n) ____ to contact each other.

A) metabolic pilus
B) asexual pilus
C) flagellum
D) cilia
E) sex pilus

Question 12

Laboratory strains of E. coli ____.

A) undergo meiosis
B) divide every 2 hours
C) can be transformed, but not conjugated
D) have been engineered to produce human insulin
E) are harmful to humans

Question 13

In Lederberg and Tatum's experiments with E. coli auxotrophs, they found that when cells of two mutant strains were cultured together, ____.

A) cells were able to grow on minimal medium supplemented with nutrients required by the first mutant strain
B) cells were able to grow on minimal medium supplemented with nutrients required by the second mutant strain
C) some cells were able to grow on minimal medium
D) no cells were able to grow on minimal medium
E) cells were able to grow in liquid medium, but not on gel-like medium containing agar

Question 14

As early as the 1940s, researchers knew that bacteria could be grown in a minimal medium containing ____ as an organic carbon source.

A) peptidase
B) glucose
C) rubisco
D) catalase
E) ammonium chloride

Question 15

Figure 17.1
Use the accompanying figure for questions 9-11.
If strains 1 and 2 conjugate and are plated on minimal medium, cells growing on the minimal medium will have the genotype ____.

A) bio- met- thr- leu+
B) bio+ met+ thr+ leu+
C) bio+ met- thr- leu+
D) bio+ met+ thr- leu+
E) bio- met- thr- leu-

Question 16

Figure 17.1
Use the accompanying figure for questions 9-11.
The gene that governs a cell's ability to synthesize biotin from inorganic precursors is labeled " bio ." The designation bio⁺indicates the ____.

A) normal allele
B) mutant allele
C) bacterium is biologically active
D) bacterium is biologically inactive
E) bacterium cannot make its own biotin

Question 17

Donor cells in conjugation are labeled ____ cells, whereas recipient cells are labeled ____ cells.

A) F⁺; F^-
B) F⁺; F⁺
C) F^-; F⁺
D) F¹; F²
E) F⁺; F²

Question 18

Conjugation is a process by which bacterial cells ____.

A) transfer DNA from one cell to another through a cytoplasmic bridge
B) release DNA into their surroundings to be taken up by neighboring bacteria
C) disrupt each other by lysing cell membranes
D) are infected with a virus
E) use a bacteriophage to carry DNA from one bacterium to another

Question 19

Bacteria ____.

A) are haploid
B) are diploid
C) are polyploid
D) have double-stranded RNA genomes
E) have single-stranded DNA genomes

Question 20

Figure 17.1
Use the accompanying figure for questions 9-11.
The gene that governs a cell's ability to synthesize methionine from inorganic precursors is labeled " met ." The designation met^-indicates the ____.

A) normal allele
B) mutant allele
C) bacterium is biologically active
D) bacterium is biologically inactive
E) bacterium can make its own methionine

Question 21

The pattern of gene transfer from Hfr to F^-cells ____.

A) occurs with genes furthest from the F factor being transferred first
B) can be used to map chromosomal genes in the F^-cell
C) was used to map the E. coli chromosome
D) cannot be used to indicate the relative positions of genes within the Hfr cell
E) is random because the F factor moves between different positions in the chromosome

Question 22

The linear DNA fragments taken up from disrupted infective cells recombine with the chromosomal DNA of the noninfective cells by ____, much in the same way as genetic recombination takes place during conjugation.

A) meiosis
B) metaphase II
C) nuclear division
D) crossovers
E) transformation

Question 23

Figure 17.2
The accompanying figure above shows the distances between genes in minutes. Assume that the time listed between two genes corresponds to the transfer time of the first of the two genes in the pair. Use the figure to answer questions 29-32.
In order to transfer gene a to an F^-cell, the sex pilus must be in place for at least ____ minutes.

A) 0
B) 6
C) 10
D) 14
E) 25

Question 24

Following genetic recombination, ____.

A) the bacterial cell is unable to divide
B) the bacterial cell is no longer able to replicate its DNA
C) the bacterial cell is a partial haploid
D) any remnants of DNA that did not contribute to the genetic recombination form plasmids
E) all progeny of the recombinant cell contain the new gene combination

Question 25

In an Hfr X F^-conjugation, ____.

A) the Hfr cell can lose chromosomal genes that it transfers to the F^-cell
B) the donor cell can become a partial diploid
C) plasmid DNA is transferred from the Hfr cell to the F^-cell
D) chromosomal DNA can be transferred from the F^-cell to the Hfr cell
E) chromosomal DNA can be transferred from the Hfr cell to the F^-cell

Question 26

Genetic recombination can occur ____.

A) during DNA replication
B) during asexual reproduction
C) during mitosis
D) from an Hfr X F^-conjugation
E) from an F⁺X F^-conjugation

Question 27

DNA can be transferred from one bacterial cell to another by ____.

A) conjugation only
B) transformation only
C) conjugation and transformation only
D) conjugation and transduction only
E) conjugation, transformation, and transduction

Question 28

During transformation, cells ____.

A) take up pieces of DNA that are released as other cells disintegrate
B) take up pieces of DNA through a viral infection
C) replicate DNA molecules
D) make replicate copies of one another
E) generate their own DNA

Question 29

A researcher exposes a nonvirulent strain of Streptococcus pneumoniae to heat-killed cells of a virulent strain. After exposure, the bacterial cells will be ____.

A) transduced
B) artificially transformed
C) transformed
D) nonvirulent
E) conjugated

Question 30

Figure 17.2
The accompanying figure above shows the distances between genes in minutes. Assume that the time listed between two genes corresponds to the transfer time of the first of the two genes in the pair. Use the figure to answer questions 29-32.
Suppose that after bacterial conjugation, the recipient cell contained the a and b genes. From this information, what can you conclude?

A) The donor cell was unable to make contact with the recipient cell.
B) The donor cell was F^-.
C) The donor cell produced an abnormal sex pilus.
D) All of the genes could not fit through the sex pilus at one time.
E) The sex pilus was broken before the rest of the genes could be transferred.

Question 31

The purpose of the sex pilus is to ____.

A) connect bacterial cells so a cytoplasmic bridge can form for conjugation
B) form a gap junction between bacterial cells for conjugation
C) block cytoplasmic exchange
D) enable bacteriophage infection
E) lyse the cell

Question 32

Hfr cells are bacterial cells that ____.

A) perform meiosis
B) have the F factor integrated into their chromosome
C) maintain the F factor in a plasmid
D) have a low frequency of recombination
E) have received DNA from a bacteriophage

Question 33

The F factor can be integrated into the bacterial chromosome through ____.

A) mitosis
B) DNA replication
C) transcription
D) crossover events
E) transduction

Question 34

The F factor contains genes that encode____.

A) lipids of the cytoplasmic bridge
B) receptor proteins on the recipient cell
C) bacteriophages
D) DNA polymerase for plasmid DNA replication
E) proteins of the sex pilus

Question 35

A colony of mice is treated with a nonvirulent strain of the bacterium Streptococcus pneumoniae . Before treatment, a researcher exposed this nonvirulent strain to heat-killed cells of a virulent strain. What will be the effect on the mouse population?

A) The mice will all remain healthy.
B) Some mice will develop a paralytic condition, but most will remain healthy.
C) Most or all of the mice will develop pneumonia.
D) Some mice will develop pneumonia, but most will remain healthy.
E) The mice will become immune to the bacteria.

Question 36

Figure 17.2
The accompanying figure above shows the distances between genes in minutes. Assume that the time listed between two genes corresponds to the transfer time of the first of the two genes in the pair. Use the figure to answer questions 29-32.
The genetic map shown in the figure was generated by identifying transferred genes after ____.

A) allowing transformation to proceed for varying amounts of time
B) allowing conjugation to proceed for varying amounts of time
C) bacterial cells were infected by various bacteriophages
D) replica plating of E. coli auxotrophs
E) allowing transduction to proceed for varying amounts of time

Question 37

Figure 17.2
The accompanying figure above shows the distances between genes in minutes. Assume that the time listed between two genes corresponds to the transfer time of the first of the two genes in the pair. Use the figure to answer questions 29-32.
According to the accompanying figure, what is the order in which the genes will be transferred to an F- cell during conjugation?

A) c-d-a-b
B) d-a-b-c
C) b-c-d-a
D) a-b-c-d
E) d-c-a-b

Question 38

R plasmids provide ____.

A) antibiotic resistance
B) a fertility factor
C) transformation ability
D) genes necessary for genetic recombination
E) nutrients

Question 39

What is the outcome of F⁺X F^-conjugation?

A) The F^-cell receives a copy of the F factor and becomes an F⁺cell.
B) The F^-cell receives a copy of the F factor but remains an F^-cell.
C) Chromosomal DNA is transferred from the F⁺cell to the F^-cell.
D) Chromosomal DNA is transferred from the F^-cell to the F⁺cell.
E) A genetic recombination of bacterial genes takes place.

Question 40

Bacterial cells that cannot readily pick up DNA molecules from their surroundings can be induced to do so by ____.

A) artificial transformation
B) double crossing-over
C) crossing-over
D) constriction
E) infection

Question 41

How does a phage transfer DNA from one bacterium to another?

A) Phages form a bridge between bacterial cells that allows DNA to pass from the host cell to the recipient cell.
B) Phages form a bridge between bacterial cells that allows DNA to pass in both directions between the two cells.
C) Phages lyse bacterial cells, releasing bacterial DNA into the environment, which is taken up by other phages for transfer to new cells.
D) When phages assemble in an infected bacterial cell, they may incorporate host DNA; released phages may attach to other cells and inject the bacterial DNA into those cells.
E) Phages attach to receptors on bacterial cells and receive some of the target cells' DNA; the phages release this DNA into the environment to be taken up by other bacterial cells.

Question 42

The two basic structural forms taken by most viruses are ____.

A) polyhedral or enveloped
B) helical or enveloped
C) helical or polyhedral
D) cylindrical or polyhedral
E) cylindrical or enveloped

Question 43

Medium that contains a full complement of nutrient substances, including amino acids and other chemicals that normal bacterial strains can synthesize themselves, is called ____ medium.

A) agar
B) minimal
C) nutritious
D) complete
E) rich

Question 44

Which statement correctly describes horizontal gene transfer?

A) Conjugation, transformation, and transduction are all forms of horizontal gene transfer.
B) Conjugation and transformation are forms of horizontal gene transfer, but transduction is a form of vertical gene transfer.
C) Eukaryote-eukaryote transfers of nuclear genes are most common.
D) Prokaryote-eukaryote transfers of nuclear genes are most common.
E) Partial diploids never result from horizontal gene transfer.

Question 45

The movement of genetic material between organisms other than by descent is called ____.

A) vertical gene transfer
B) horizontal gene transfer
C) parallel gene transfer
D) sexual reproduction
E) asexual reproduction

Question 46

In transduction, bacterial cells ____.

A) take up pieces of DNA that are released as other cells disintegrate
B) receive DNA from an infecting phage
C) replicate DNA molecules
D) make replicate copies of one another
E) generate their own DNA

Question 47

A researcher is looking for met^-strains. He compares two plates. One plate has colonies growing on complete medium. The other plate has colonies growing on methionine-deficient medium. How can the researcher determine which colonies are met^-?

A) The colonies growing on the methionine-deficient plate are met^-.
B) Colonies growing on the complete medium, but not on the methionine-deficient medium are met^-.
C) More experiments must be performed to identify the met^-colonies.
D) All of the colonies growing on the complete medium are met^-.
E) Colonies growing on the methionine-deficient medium, but not on complete medium are met^-.

Question 48

If a phage is carrying host cell DNA fragments inside its capsid and then infects another bacterial cell, ____.

A) it causes the recipient bacterium to shrink in size
B) it kills the recipient bacterium in a matter of minutes
C) it assembles a new organism that is a cross between the phage and the recipient bacterium
D) it will not kill the recipient because it lacks the bacteriophage genome.
E) it transforms the new recipient into a bacteriophage

Question 49

The core of a virus is a ____ molecule.

A) protein
B) sugar
C) nucleic acid
D) fat
E) phosphate

Question 50

A complete viral particle is called a ____.

A) capsule
B) virion
C) capsid
D) viroid
E) prophage

Question 51

All viruses ____.

A) are parasites of the host they infect
B) replicate in the same way
C) share the same structure
D) use the same mechanisms for gene expression
E) enter host cells in the same manner

Question 52

Exposing E. coli to calcium ions and DNA and then incubating the culture at low temperatures in the presence of ice followed by a quick heat shock induces ____.

A) artificial transformation
B) a double crossover
C) a single crossover
D) DNA replication
E) infection

Question 53

Electroporation ____.

A) exposes cells briefly to rapid pulses of electrical current to induce transformation
B) exposes cells to calcium ions to induce transformation
C) exposes cells to calcium ions to induce transduction
D) inserts the foreign DNA into chloroplast DNA
E) inserts the foreign DNA into mitochondrial DNA

Question 54

A plate of solid growth medium with colonies on it is pressed gently onto sterile velveteen. The velveteen "stamp" is used to make identical plates. This technique is called ____.

A) replication
B) replica plating
C) plating
D) plate making
E) horizontal gene transfer

Question 55

All viruses have genes encoding ____.

A) the proteins of their capsid
B) enzymes required for nucleic acid replication
C) the proteins of their capsid and enzymes required for nucleic acid replication
D) a plasma membrane
E) the proteins of their capsid and a plasma membrane

Question 56

What happens when a phage containing bacterial DNA attaches to and injects DNA into another bacterial cell?

A) The phage is destroyed.
B) The phage replicates.
C) The bacterial cell dies from the phage infection.
D) The bacterial cell lives and produces many copies of the phage.
E) The bacterial cell becomes a partial diploid and may undergo genetic recombination.

Question 57

Viruses ____.

A) can reproduce independently
B) are made up of cells
C) grow and develop
D) generate metabolic energy
E) adapt very readily over time

Question 58

All viruses must contain ____.

A) proteins
B) carbohydrates and proteins
C) proteins and nucleic acids
D) nucleic acids
E) carbohydrates, proteins, lipids, and nucleic acids

Question 59

Transformation is used in genetic engineering to ____.

A) generate bacteria with an F factor for conjugation
B) understand how bacteriophages transfer DNA to bacteria
C) obtain large quantities of viruses for study
D) produce large quantities of the inserted DNA in order to increase yields of the target product
E) introduce new genes into a bacterium's mitochondrial DNA

Question 60

Bacteria that undergo natural transformation ____.

A) are very common
B) are strains of E. coli
C) are subjected to electroporation to induce DNA uptake
D) generally have a DNA-binding protein on the exterior of their cell wall
E) integrate foreign DNA into their chromosome through conjugation

Question 61

Bacteriophage lambda ____.

A) is a temperate phage
B) is a virulent phage
C) infects plant cells
D) infects animal cells
E) is a T-even phage

Question 62

For some virulent phages, fragments of the host DNA may be included in the heads as the viral particles assemble, providing the basis for ____.

A) transformation
B) transmutation
C) metabolism
D) specific transduction
E) generalized transduction

Question 63

Retroviruses ____.

A) have DNA genomes
B) use an RNA intermediate to replicate their genome
C) replicate their RNA genome directly to produce progeny RNA genomes
D) do not have an envelope
E) require reverse transcriptase to replicate their genome

Question 64

Arrange the following steps of the HIV life cycle in order: 1.Viral RNAs and proteins assemble into new viral particles that bud from the cell.
2)DNA copy of the viral genome is integrated into the host genome.
3)Viral reverse transcriptase makes a double-stranded DNA copy of the viral RNA genome.
4)Viral particle enters the cell.
5)The provirus is transcribed into viral RNA genomes and mRNAs to make viral proteins.

A) 3,2,5,1,4
B) 2,3,4,5,1
C) 4,2,3,1,5
D) 2,4,3,5,1
E) 4,3,2,5,1

Question 65

Prions ____.

A) are more complex than viruses
B) have large DNA genomes
C) cause neurodegenerative disorders in mammals
D) infect plant cells
E) encode their own polymerases for nucleic acid replication

Question 66

During the ____ cycle, viral DNA, which has been inserted into the host DNA, remains mostly or completely inactive, but is replicated and passed onto host cell progeny.

A) lytic
B) lysogenic
C) Krebs
D) citric acid
E) lytic or lysogenic

Question 67

Viroids ____.

A) are more complex than viruses
B) have large DNA genomes
C) encode their own polymerase for nucleic acid replication
D) cause diseases in plants
E) infect animal cells

Question 68

The series of events from infection of a cell through the release of progeny phages from a lysed cell is called the ____ cycle.

A) lytic
B) lysogenic
C) Krebs
D) citric acid
E) lytic or lysogenic

Question 70

Viruses with a tail attached at one side of a polyhedral head are called ____.

A) simple viruses
B) helical viruses
C) enveloped viruses
D) complex viruses
E) viroids

Question 71

Which of the following diseases is not caused by prions?

A) Creutzfeldt-Jakob disease
B) mad cow disease
C) Marburg hemorrhagic fever
D) bovine spongiform encephalopathy
E) kuru

Question 72

Some animal viruses may enter a ____ stage in which the virus remains in the cell in inactive form.

A) latent
B) virulent
C) temperate
D) transformation
E) lytic

Question 73

Lederberg and Tatum used the bacterial strains bio^-met^-leu⁺thr⁺thi⁺and bio⁺met⁺leu^-thr^-thi^-in their experiments to determine if genetic recombination occurs in bacteria. Would it have been better to use two strains with the genotypes met^-leu⁺and met⁺leu^-instead?

A) Yes, because it is easier to study two genes than five genes.
B) Yes, because the met^-leu⁺and met⁺leu^-strains only have one mutation, which makes it easier for genetic recombination to occur.
C) No, because the met^-leu⁺and met⁺leu^-strains only have one mutation. A single random mutation could restore methionine or leucine synthesis in the strains.
D) No, because strains with only one nutrient-deficient gene can still grow on minimal medium.
E) No, because cells have two genes that encode different versions of leucine, so the met⁺leu^-strain would still be able to grow on minimal medium.

Question 75

A virus in a lysogenic cycle is referred to as a ____.

A) prophage
B) virulent phage
C) artificial phage
D) T-even phage
E) lytic phage

Question 76

Temperate bacteriophages ____.

A) kill their hosts during each cycle of infection
B) infect only animals
C) may enter an inactive phase in which they do not kill their host
D) are enveloped viruses
E) infect organisms living in temperate environments

Question 77

Enveloped viruses ____.

A) generally lyse host cells as they are released
B) synthesize envelope lipids as they replicate within the host cell
C) acquire their envelope as they bud from the host cell
D) acquire their envelope as they enter the host cell
E) always contain DNA genomes

Question 78

Viruses that kill bacterial host cells during each cycle of infection are called ____.

A) virulent bacteriophages
B) enveloped viruses
C) temperate bacteriophages
D) phages
E) nonvirulent bacteriophages

Question 79

What is the main difference between a virulent and temperate bacteriophage?

Question 80

T-even bacteriophages ____.

A) infect E. coli
B) are nonvirulent
C) consist of a head with no tail
D) contain two molecules of double-stranded DNA in their head
E) are temperate bacteriophages that do not have a lytic cycle