Home > 18: The Genetics of Viruses and Bacteria > Chapter Quiz
 
 
Chapter 18: The Genetics of Viruses and Bacteria
 
Chapter Quiz
 

Chapter Quiz


1 .       Viruses can vary with respect to all of the following characteristics except _____. (Concept 18.1E-Book) [Hint]

 DNA or RNA as the genetic material
 presence or absence of metabolic machinery
 single- or double-stranded nucleic acids
 presence or absence of a membranous envelope
 the type of host cell it can infect
2 .       A microbiologist analyzes chemicals obtained from an enveloped RNA virus that infects monkeys. He finds that the viral envelope contains a protein characteristic of monkey cells. Which of the following is the most likely explanation? (Concept 18.1E-Book) [Hint]

 The viral envelope forms as the virus leaves the host cell.
 The virus forced the monkey cell to make proteins for its envelope.
 The virus is a prophage.
 Its presence is a result of the monkey's immunological response.
 The virus fools its host by mimicking its proteins.
3 .       Which one of the following, if any, is never a component of any virus? (Concept 18.1E-Book) [Hint]

 protein
 double-stranded (ds) DNA
 phospholipid bilayer
 single-stranded (ss) RNA
 All of the above can be components.
4 .       Viruses that infect bacteria are called _____. (Concept 18.1E-Book) [Hint]

 bacterioviruses
 bacteriophages
 capsomeres
 proviruses
 retroviruses
5 .       HIV, the virus that causes AIDS, only infects certain cells within the immune system. This is because _____. (Concept 18.1E-Book) [Hint]

 the virus is not very mobile within the body and only comes into contact with a limited number of immune cells
 other cells produce toxins that destroy the virus before infection can take place
 the virus binds to specific receptors that are only present on certain immune cells
 the virus gets into all cells, but the viral RNA is immediately destroyed in all but a small number of immune system cells
 infection requires the presence of a specific DNA sequence that is only present in the genome of certain immune system cells
6 .       When a virus infects an E. coli cell, what part of the virus enters the bacterial cytoplasm? (Concept 18.1E-Book) [Hint]

 the entire virus
 only the nucleic acid
 the protein capsid and enclosed nucleic acid
 the tail fibers
 the protein capsid only
7 .       The phage reproductive cycle that kills the bacterial host cell is a _____ cycle, and a phage that always reproduces this way is a _____ phage. (Concept 18.1E-Book) [Hint]

 lytic ... virulent
 lytic ... lysogenic
 lysogenic ... temperate
 virulent ... lytic
 lysogenic ... virulent
8 .       In the lytic life cycle of phages _____. (Concept 18.1E-Book) [Hint]

 the cell typically dies, releasing many copies of the virus
 the viral capsid is assembled according to the genetic information of the bacterium
 the entire phage is taken into the bacterium
 DNA replication is not part of the life cycle
 phage DNA is incorporated into the host cell's genome
9 .       Restriction enzymes help defend bacteria against viral infections by _____. (Concept 18.1E-Book) [Hint]

 preventing the binding of the virus to the cell surface
 preventing entry of the viral DNA into the cell
 cutting viral DNA once it has entered the cell
 preventing the synthesis of viral capsomeres in the cell
 preventing integration of the viral genome into the host chromosome
10 .       A phage that inserts itself into the host DNA is called _____. (Concept 18.1E-Book) [Hint]

 a bud
 lysogenic
 a bacteriophage
 semipermeable
 a capsomere
11 .       A prophage is a(n) _____. (Concept 18.1E-Book) [Hint]

 emerging virus
 virus that infects bacteria
 type of retrovirus
 prion that has been integrated into a bacterial cell's chromosome
 viral genome that has been incorporated into a bacterial cell's chromosome
12 .       In the lysogenic cycle of phages _____. (Concept 18.1E-Book) [Hint]

 the nucleic acid core of the phage is all that enters the host cell
 only a small number of the viral genes are expressed
 the viral nucleic acid inserts itself into the host chromosome
 the viral nucleic acid is replicated along with the host DNA
 all of the above
13 .       How do retroviruses, such as HIV, differ from other viruses? (Concept 18.1E-Book) [Hint]

 They have much simpler reproductive cycles than other RNA viruses.
 They contain DNA that is used as a template to make RNA.
 They can reproduce only inside living cells.
 They contain nucleic acids that code for proteins.
 They contain the enzyme reverse transcriptase.
14 .       Reverse transcription, carried out by retroviruses, is the process by which _____. (Concept 18.1E-Book) [Hint]

 DNA information is copied into RNA
 RNA information is copied into DNA
 RNA information is "read" to form a protein molecule
 DNA is duplicated
 information is copied from a protein molecule into RNA
15 .       Which statement below is a correct comparison of a "regular" RNA virus and a RNA retrovirus? (Concept 18.1E-Book) [Hint]

 Only the regular RNA virus performs transcription.
 Only the RNA retrovirus performs translation.
 Only the regular RNA virus produces DNA from an RNA template.
 Only RNA retroviruses produce DNA using DNA replicase.
 Both produce protein coats via translation of mRNA.
16 .       The symptoms of a viral infection in a person can be caused by _____. (Concept 18.2E-Book) [Hint]

 the death of infected cells
 the reaction of the individual's immune system to the infection
 the production of toxins by infected cells
 toxic viral components, such as envelope proteins
 all of the above
17 .       Vaccines for viral diseases are _____ and help prevent infection by _____. (Concept 18.2E-Book) [Hint]

 harmless derivatives of pathogenic viruses ... stimulating the immune system to mount a defense against the actual pathogen
 nucleoside inhibitors ... inhibiting the replication of the viral genome
 protease inhibitors ... preventing synthesis of envelope proteins
 antibiotic formulations ... specifically killing infected cells
 antibiotic formulations ... killing bacteria that assist viruses in infecting animal cells
18 .       Emerging viruses can originate from all of the following sources except _____. (Concept 18.2E-Book) [Hint]

 animal viruses
 the mutation of existing human viruses
 human genes that mutate in such a way as to make them resemble viruses
 viruses previously confined to small, isolated populations that can now spread due to technological or social changes such as the development of affordable international travel
 All of the above are possible sources of emerging viruses.
19 .       Which of the following is an example of vertical transmission of a virus in plants? (Concept 18.2E-Book) [Hint]

 Viral particles are carried by the wind from one plant to another.
 Viral particles are carried from one plant to another by a pair of pruning shears.
 Two neighboring plants touch each other, allowing viruses present in one plant to infect the other plant.
 An infected plant produces seeds that contain the virus, giving rise to infected progeny.
 All of the above are correct.
20 .       Circular RNA molecules that function like a virus in plants are termed _____. (Concept 18.2E-Book) [Hint]

 rhabdovirus
 viroid
 retrovirus
 prion
 none of the above
21 .       Prions are _____ that are thought to cause disease by _____. (Concept 18.2E-Book) [Hint]

 abnormally shaped proteins ... inducing similar but normally shaped proteins in the brain to adopt the abnormal form
 RNA molecules ... encoding toxic proteins
 mutant DNA molecules ... encoding toxic proteins
 an abnormal type of capsid ... dramatically enhancing the rate of viral infection
 DNA molecules ... jumping around the genome and mutating genes
22 .       How does a bacterial chromosome differ from a eukaryotic chromosome? (Concept 18.3E-Book) [Hint]

 A bacterial chromosome is mainly a circular, single-stranded DNA molecule. A eukaryotic chromosome is mainly a linear, single-stranded DNA molecule with many associated proteins.
 A bacterial chromosome is a circular, double-stranded DNA molecule with associated proteins. A eukaryotic chromosome is a linear, double-stranded DNA molecule with many associated proteins, including histones.
 A bacterial chromosome is a circular, double-stranded DNA molecule with associated histone proteins. A eukaryotic chromosome is a linear, double-stranded DNA molecule with many associated proteins.
 A bacterial chromosome is a linear, double-stranded DNA molecule with many associated proteins. A eukaryotic chromosome is a circular, double-stranded DNA molecule with very few attached protein molecules.
 A bacterial chromosome has a circular, double-stranded DNA molecule. A eukaryotic chromosome has a circular, double-stranded DNA molecule with many associated proteins.
23 .       If you observe that a cell contains _____, you can conclude that it is a eukaryote, rather than a prokaryote. (Concept 18.3E-Book) [Hint]

 ribosomes
 several complex chromosomes
 a true cell membrane
 a single circular chromosome
 a nucleoid
24 .       In prokaryotic DNA replication _____. (Concept 18.3E-Book) [Hint]

 the new DNA molecule is formed when plasmids collect around the chromosome, depolymerize, and then polymerize again in a complementary base sequence
 the chromosomes condense and gather on the equatorial plate and then move to the spindle poles without using any microtubules
 a single replication fork opens and proceeds around the molecule in both directions. Then the cell elongates to pull the two pieces of DNA apart.
 the cell divides before DNA replicates, and then replication occurs separately in each daughter cell
 one of the daughter chromosomes consists of two new DNA strands and the other daughter chromosome consists of the two original strands
25 .       Which of the following is not a way that a bacterial population can acquire increased genetic variation? (Concept 18.3E-Book) [Hint]

 transduction
 conjugation
 binary fission
 mutation
 transformation
26 .       A microbiologist found that a clone of bacteria infected by a phage had developed the ability to make a particular amino acid that the bacteria could not make before the infection. This new ability was probably a result of _____. (Concept 18.3E-Book) [Hint]

 transformation
 natural selection
 conjugation
 spontaneous mutation
 transduction
27 .       Sometimes genes are transferred between bacteria when a bacteriophage packages bacterial DNA into the capsid instead of viral DNA. This process is called _____. (Concept 18.3E-Book) [Hint]

 generalized transduction
 conjugation
 specialized transduction
 binary fission
 transformation
28 .       The primary difference between bacterial "sex" (conjugation) and sexual reproduction in plants and animals is that _____. (Concept 18.3E-Book) [Hint]

 bacterial sex involves more than two individuals
 bacterial sex involves the transfer of genetic material from an F+ or Hfr cell to an F- cell and a reciprocal transfer from the F- cell
 bacteria exchange RNA, not DNA
 bacterial sex does not produce offspring
 eggs and sperm are different, but bacterial gametes are all alike
29 .       The ability of an E. coli bacterium to act as a donor "male" during conjugation is usually due to a piece of DNA called _____. (Concept 18.3E-Book) [Hint]

 a probe
 a plasmid
 recombinant DNA
 an F factor
 a Ti plasmid
30 .       Much of genetic engineering involves the use of plasmids, which are _____. (Concept 18.3E-Book) [Hint]

 repeated sequences that protect DNA from digestion when it is inserted into a foreign cell
 small circlets of DNA found in bacteria
 segments of RNA that must be attached to DNA before the DNA can replicate
 ends of cut DNA molecules that are "sticky" because they have unpaired base sequences
 infectious proteins
31 .       A microbiologist analyzed the DNA of two E. coli cells, an Hfr cell and an F- cell, before and immediately after their conjugation. He found that _____. (Concept 18.3E-Book) [Hint]

 both cells lost some genes and gained others
 both cells gained genes but lost none of their original genes
 one cell lost genes and the other gained genes
 one cell gained genes and the genes of the other were unchanged
 the genes of both cells remained unchanged
32 .       Which of the following is true with regard to antibiotic resistance? (Concept 18.3E-Book) [Hint]

 If individual bacterial cells are killed quickly enough, they don't have time to become resistant to the antibiotic.
 The resistant cells can be resistant to only one antibiotic.
 Indiscriminate use of antibiotics is prohibited by federal laws.
 New antibiotics are useful for many years before resistant strains start appearing.
 The resistance can be transferred from one bacterial species to another.
33 .       R plasmids can cause medical problems because they _____. (Concept 18.3E-Book) [Hint]

 control conjugation in bacteria
 are used as vectors to transfer genes to plants
 make bacteria resistant to antibiotics
 code for DNA polymerase
 protect bacteria against mutations
34 .       The simplest bacterial transposons are _____. (Concept 18.3E-Book) [Hint]

 operons
 composite transposons
 F plasmids
 prophages
 insertion sequences
35 .       A bacterium can make the amino acid glycine or absorb it from its surroundings. A biochemist finds that glycine binds to a repressor protein and causes the repressor to bind to the bacterial chromosome, turning off an operon. If it is like other operons, the presence of glycine will result in the _____. (Concept 18.4E-Book) [Hint]

 inhibition of bacterial cell division
 breakdown of glycine
 cessation of the synthesis of glycine
 formation of sex pili
 manufacture of the repressor protein
36 .       "Feedback inhibition" refers to the _____. (Concept 18.4E-Book) [Hint]

 inhibition of enzymes involved in a metabolic pathway by the pathway's end product
 repression of an operon in the absence of an inducer
 activation of an operon in the absence of a corepressor
 silencing of viral genes in a prophage
 inhibition of the replication of viral genomes by nucleoside analogs
37 .       Operons function in prokaryotes to _____. (Concept 18.4E-Book) [Hint]

 regulate the catalytic activities of specific proteins
 regulate the rate of transcription
 phosphorylate specific polypeptide chains
 degrade proteins
 none of the above
38 .       A repressible operon _____. (Concept 18.4E-Book) [Hint]

 is usually in the on position
 requires the presence of the encoded gene's end product to activate its repressor
 is exemplified by the lac operon
 The first and second choices are correct.
 The first three choices are correct.
39 .       In general, operons that encode the enzymes of a biosynthetic (anabolic) pathway (such as the trp operon) are _____, and those encoding the enzymes of a catabolic pathway (such as the lac operon) are _____. (Concept 18.4E-Book) [Hint]

 repressible ... inducible
 inducible ... repressible
 permanently on ... permanently off
 permanently off ... permanently on
 easily mutated ... resistant to mutations
40 .       An inducible system _____. (Concept 18.4E-Book) [Hint]

 is usually turned off
 requires an inducer molecule to inactivate its repressor
 is exemplified by genes that are always expressed
 The first two choices are correct.
 The first three answers are correct.
41 .       In an inducible operon, the inducer is often the _____ in the pathway being regulated; the inducer binds to the _____, thus rendering it _____. (Concept 18.4E-Book) [Hint]

 end product ... corepressor ... inactive
 end product ... repressor ... inactive
 substrate ... corepressor ... inactive
 substrate ... repressor ... active
 substrate ... repressor ... inactive
42 .       You have inserted the gene for human growth factor into the E. coli lactose operon, replacing the structural genes with the gene for human growth factor. What substance must you add to your culture of bacteria to cause them to produce human growth factor for you? (Concept 18.4E-Book) [Hint]

 repressor protein
 operator protein
 human growth factor
 allolactose
 any of the above substances
43 .       In general, the lactose operon _____. (Concept 18.4E-Book) [Hint]

 continuously produces beta-galactosidase until all of the lactose is used up
 is transcribed only in the presence of lactose
 is transcribed when allolactose binds to the lactose repressor protein
 cannot be transcribed in the presence of the active lactose repressor
 all of the above
44 .       When the lac operon is strongly active, _____. (Concept 18.4E-Book) [Hint]

 glucose levels are high
 cAMP levels are high
 allolactose is absent
 the lac repressor protein is active
 all of the above





©2005 Pearson Education, Inc., publishing as Benjamin Cummings