Chapter 18- Genetics of Viruses and Bacteria

In the presence of a regulatory protein the lac operon is A)transcribed B) not transcribed C) transcribed at a faster than usual rate D) is turned on E) either transcribed or not transcribed

B) not transcribed

The AIDS virus uses which one of the following to read RNA and synthesize the corresponding DNA? A) transcription B) reverse transcription C) translation D) reverse translation E) conjugation

B) reverse transcription

______ are naked strands of RNA and ______ are infectious protein particles A) Retroviruses ... transposons B) Retrotransposons ... viruses C) Prophages ... bacteriophages D) Phages ... prions E) Viroids ... prions

E) Viroids ... prions

Which of the following is a characteristic of all viruses? A) nucleic acid genome B) a protein capsid C) glycoprotein cell wall D) A and B only E) A, B, and C

D) A and B only

Virulent phages undergo a(n) __________ life cycle, whereas temperate phages are capable of undergoing a(n) __________ cycle. A) infective; retroviral B) infective; benign C) retroviral; infective D) lysogenic; lytic E) lytic; lysogenic

E) lytic; lysogenic

Viral DNA makes mRNA by the process of A) replication B) infection C) translation D) lysis E) transcription

E) transcription

A phage is a A) virus that infects bacteria B) virus- infected bacterium C) protein shell enclosing a viral genome D) lysed bacterium E) viral genome

A) virus that infects bacteria

Double-stranded viruses can reproduce the lytic cycle and the lysogenic cycle. Which of the following is characterstic of the lytic cycle? A) Many bacterial cells containing viral DNA are produced. B) Viral DNA is incorporated into the host chromosomes. C) A large number of phages are released at a time. D) The virus-host relationship usually lasts for generations. E) The viral genome replicates without destroying the host.

C) A large number of phages are released at a time

HIV is responsible for A) PKU B) TB C) STD D) CPR E) AIDS

E) AIDS

A protein shell enclosing a viral genome is known as a(n) A) capsule B) envelope C) phage D) capsid E) prophage

D) capsid

What is the source of a viral envelope? A) host cell DNA B) prophages C) provirus D) host cell membrane E) viral glycoproteins

D) host cell membrane

What are prions? A) misfolded versions of normal brain protein B) tiny molecules of RNA that infect plants C) viral DNA that has had to attach itself to the host genome D) viruses that invade bacteria E) a mobile segment of DNA

A) misfolded versions of normal brain protein

The phage DNA is not hydrolyzed with the host DNA because A) phage DNA contains an urecognizable form of cytosine. B) lysozyme releases phage particles before hydrolysis can occur. C) the host cell ceases to function. D) phage DNA remains outside the host cell. E) a protein sheath protects phage DNA.

A) phage DNA contains an urecognizable form of cytosine.

Viruses have some of the properties of living organisms. Which of the following is a characteristic of all organisms, but not of viruses? A) plasma membrane B) ability to control metabolism C) genetic information stored as nucleic acid D) structure includes proteins E) ability to reproduce

A) plasma membrane

Of the following, which is least related to the others? A) prion B) operator C) promoter D) regulatory gene E) repressor

A) prion

Which of the following contributes to the emergence of viral disease? A).production of new virus strains through mutation B).spread of existing virus from one host species to another C) Transformation from lytic to lysogenic activity D) .A and B only E) A, B, and C

A) production of new virus strains through mutation

Regulatory proteins bind to A) the operator B) the lactose-utilization genes C) the regulatory gene D) RNA polymerase E) transcription factors

A) the operator

DNA is transferred from one bacterium to another by a virus. A) transduction B) transposition C) translation D) transformation E) conjugation

A) transduction

The simplest infectious biological systems are A) viroids. B) viruses. C) bacteria. D) A and B. E) B and C.

A) viroids.

The nucleic acid of a virus particle is enclosed in a protein coat known as a(n) A) nuclear envelope B) capsid C) head D) envelope E) genome

B) Capsid

Which one of the following best describes the general mode of action of a virus? A)The viral protein inhibits the host protein. B) The viral genome "takes over" the host cell's central dogma machinery. C) The viral protein causes host RNA to be expressed differently. D) The viral envelope inhibits the host's DNA. E) The viral envelope destroys the host's plasma membrane.

B) The viral genome "takes over" the host cell's central dogma machinery.

Which of the following is a true statement about viruses? A) A single virus particle contains both DNA and RNA. B) Viruses are classified below the cellular level of biological organization. C) Even small virus particles are visible with light microscopes. D) A and B only are true. E) A, B, and C are true

B) Viruses are classified below the cellular level of biological organization.

Viral envelopes are generally A) made of peptidoglycan cell wall material. B) composed of a lipid bilayer. C) found between the viral protein coat and its DNA. D) composed of protein. E) composed of single-stranded RNA.

B) composed of a lipid bilayer.

What does bacterial mating involve? A) exchange of egg and sperm B) formation of a cytoplasmic bridge for the transfer of "male" DNA C) sex pili that draw the cells together so that mRNA can be inserted D) integration of male and female DNA into a cytoplasmic bridge E) binary fission of a bacterial cell

B) formation of a cytoplasmic bridge for the transfer of "male" DNA

What is the most common source of genetic diversity in a bacterial colony? A) Plasmids B) mutation C) crossing over D) transposons E) meiotic recombination

B) mutation

Viruses have some of the properties of living organisms. Which of the following is a characteristic of all organisms, but NOT of all viruses? A) ability to control metabolism B) plasma membrane C) genetic information stored as a nucleic acid D) ability to reproduce E) structure to include proteins

B) plasma membrane

Bacteriophage DNAs that have become integrated into the host cell chromosome are called A) transposons. B) prophages. C) T-even bacteriophages. D) plasmids. E) intemperate bacteriophages.

B) prophages.

Double-stranded viral DNA is incorporated into a host cell as a A) promoter B) provirus C) transposon D) lac E) homeoboxes

B) provirus

Viruses that have a single strand of RNA that acts as a template for DNA synthesis are known as A) lytic phages. B) retroviruses. C) proviruses. D) bacteriophages. E) viroids.

B) retroviruses.

The genetic material of HIV consists of A) single-stranded DNA B) single-stranded RNA C) double-stranded DNA D) double-stranded RNA E) none of the above

B) single-stranded RNA

When a lysogenic phage infects a bacterial cell, all of the following happen EXCEPT A) viral DNA is injected into the bacterium B) the cell is immediately lysed by the invasion C) viral DNA becomes inserted into the bacterial chromosome D) when the bacterial chromosome replicates, viral DNA is also replicated E) all bacterial descendants will carry the viral genes

B) the cell is immediately lysed by the invasion

As a result of the lytic cycle A) the host cell is not destroyed B) the host cell's DNA is destroyed C) viral ribosomes are produced D) viral DNA is incorporated into host cell DNA E) a prophage is created

B) the host cell's DNA is destroyed

A sequence of DNA is moved to alternative locations within the genome A) transduction B) transposition C) translation D) transformation E) conjugation

B) transposition

A geneticist found a particular nucleotide sequence on different chromosomes in different mouse skin cells. This suggested that A) transformation was occurring in some skin cells B) transposons were moving around C) the cells were engaging in conjugation D) the mouse had been exposed to a mutagen E) the mouse responded to a vaccine

B) transposons were moving around

What is the function of reverse transcriptase in retroviruses? A) It converts host cell RNA into viral DNA. B) It hydrolyzes the host cell's DNA. C) It uses viral RNA as a template for DNA synthesis. D) It translates viral RNA into proteins. E) It uses viral RNA as a template for making complementary RNA strands.

C) It uses viral RNA as a template for DNA synthesis.

A mutation in this section of DNA could influence the binding of RNA polymerase to the DNA A) operon B) operator C) Promoter D) Repressor E) Corepressor

C) Promoter

A plant that has been raised in a sterile environment shows symptoms of a viral infection. How would you explain this? A) The viral infection was acquired by horizontal transmission. B) A group of plant genes mutated to become a viral genome. C) The viral infection was acquired by vertical transmission. D) The viral infection was acquired from the environment. E) A plant raised in a sterile environment cannot show symptoms of viral infection.

C) The viral infection was acquired by vertical transmission.

One of the ways you could tell a prokaryotic cell from a eukaryotic cell is that only the prokaryotic cell would A) be bigger B) have a nucleus C) have circular DNA molecules concentrated in a region called the nucleoid D) have a true cell membrane E) contain mitochondria

C) have circular DNA molecules concentrated in a region called the nucleoid

Which of these is NOT a component of the lac operon? A) lactose-utilization genes only B) promoter only C) regulatory gene only D) operator only E) promoter and operator

C) regulatory gene only

What is the function of the single-stranded RNA in certain animal viruses? A) It is used as a template for the synthesis of DNA. B) It codes for an mRNA. C) It becomes an mRNA. D) A and C only are correct. E) A, B, and C are all correct.

D) A and C only are correct.

The operon model of the regulation of gene expression in bacteria was proposed by A) Watson and Crick B) Franklin C) Darwin D) Jacob and Monod E) Mendel

D) Jacob and Monod

Which of the following is not a reason scientists suspected that something other than bacteria was the cause of tobacco mosaic disease? A) Passing infectious sap through a fine filter failed to remove the infectious agent. B) Treating infectious sap with alcohol failed to remove the infectious agent. C).No cells could be seen in the infectious sap using a light microscope. D) The infectious agent in the sap could reproduce, as its ability to cause disease was undiluted even after many transfers from plant to plant. E) The infectious agent could not be cultivated on nutrient media in petri dishes or in test tubes.

D) The infectious agent in the sap could reproduce, as its ability to cause disease was undiluted even after many transfers from plant to plant.

A researcher lyses a cell that contains nucleic acid molecules and capsid units of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur? A) The plants would develop some but not all of the symptoms of the TMV infection. B) The plants would develop symptoms typically produced by viroids. C) The plants would become infected, but the sap from these plants would be unable to infect other plants. D) The plants would develop the typical symptoms of TMV infection. E) The plants would not show any disease symptoms

D) The plants would develop the typical symptoms of TMV infection.

A correct sequence of DNA segments composing an operon is A) regulatory gene, promoter, operator, enzyme-coding genes B) lacI, promoter, operator, lacZ, lacY, lacA C) enzyme-coding genes, promoter, operator D) promoter, operator, enzyme-coding genes E) prophage, operator, enzyme-coding genes

D) promoter, operator, enzyme-coding genes

External DNA is assimilated by a cell. A) transduction B) transposition C) translation D) transformation E) conjugation

D) transformation

What is the function of reverse transcriptase in retroviruses? A) translates viral RNA into proteins B) hydrolyzes the host cell's DNA C) uses viral RNA as a template for making complementary RNA strands D) uses viral RNA as a template for DNA synthesis E) converts host cell RNA into viral DNA

D) uses viral RNA as a template for DNA synthesis

What is the function of reverse transcriptase? A) It catalyzes the formation of a polypeptide from an RNA template. B) It catalyzes the formation of DNA from a polypeptide template. C) It catalyzes the formation of RNA from a polypeptide template. D) It catalyzes the formation of RNA from a DNA template. E) It catalyzes the formation of DNA from an RNA template

E) It catalyzes the formation of DNA from an RNA template

The host range of a virus is determined by A) the structure of the viral capsid. B) whether the virus nucleic acid is DNA or RNA. C) proteins on the surface of the cell. D) enzymes produced by the virus before it infects the cell. E) both A and C.

E) both A and C.

A lack of this nonprotein molecule would result in the inability of the cell to "turn off" genes A) operon B) operator C) Promoter D) Repressor E) Corepressor

E) corepressor

horizontal transmission of a plant viral disease could be caused by A)the movement of viral particles through plasmodesmata B) the inheritance of an infection from a parent plant C) the spread of an infection by vegetative propagation D) the transmission of proviruses via cell division E) insects as vectors carrying virus particles between plants

E) insects as vectors carrying virus particles between plants

The lac operon governs the expression of genes connected with A) prophage integration B) provirus integration C) lactate production D) lactose production E) lactose utilization

E) lactose utilization

Viral DNA incorporated into a host cell DNA is known as a(n) A) capsule B) envelope C) phage D) capsid E) prophage

E) prophage

The lytic cycle of bacteriophage infection ends with the A) replication of viral DNA B) entry of the phage protein coat into the host cell C) assembly of viral particles into phages D) the injection of phage DNA into a bacterium E) rupture of the bacterium

E) rupture of the bacterium

Viruses are referred to as obligate parasites because A) viral DNA inserts itself into host DNA. B) they reproduce and then exit the cell. C) they are nonliving. D) they use the host's energy to live. E) they use the host cell's nucleotides and enzymes to reproduce.

E) they use the host cell's nucleotides and enzymes to reproduce.

In the lysogenic cycle A) host DNA is destroyed and viral DNA is replicated B) a bacterium replicates without passing viral DNA to its daughter cells C) viral DNA is destroyed and host DNA is replicated D) a bacterium divides once before the lytic cycle is initiated E) viral DNA is replicated along with host DNA

E) viral DNA is replicated along with host DNA