Exam 4

Question 1

A mutant that has a nutritional requirement for growth is an example of a(n):

Answer 1

Auxotroph

Question 2

The phage Mu:

Answer 2

Replicates by transposition

Question 3

A mutation that readily reverses to restore the original parental type would most likely be due to a(n):

Answer 3

Point mutation

Question 4

Ionizing radiation does NOT include:

Answer 4

UV rays

Question 5

The uptake of DNA released from a cell is ___, while transfer of DNA with cell-to-cell contact would most likely result in ___.

Answer 5

Transformation / conjugation

Question 6

A plasmid may:

Answer 6

Replicate independently of the chromosome, integrate into the chromosome, or be transferred cell-to-cell during conjugation

Question 7

Plasmids that govern their own transfer are known as:

Answer 7

Conjugative

Question 8

Which of the following would NOT be a trait of a resistance plasmid?

Answer 8

It increases the hosts growth rate

Question 9

Hfr strains of Escherichia coli:

Answer 9

Have an integrated F factor

Question 10

The collective term for the organisms living on or in the human body is:

Answer 10

Normal microbial flora

Question 11

The dose of an antigen that kills 50% of animals in a test group and is used to estimate the virulence of a pathogen is known as:

Answer 11

LD50 (lethal dose 50)

Question 12

Which of the following is most similar to lysogeny?

Answer 12

Hfr state

Question 13

The vagina of an adult female is:

Answer 13

Weakly acidic

Question 14

Virulence is the relative ability of a ___ to cause disease.

Answer 14

Pathogen

Question 15

Microinsertions and microdeletions often result in ___ mutations.

Answer 15

Frameshift

Question 16

If a bacterium carrying a plasmid that confers resistance to ampicillin is placed into medium without ampicillin, it may:

Answer 16

Lose the plasmid because there is no selection for ampicillin

Question 17

The Baltimore scheme to classify viruses contains a total of ___ groups based on ___.

Answer 17

Seven / genome composition and transcription mechanism

Question 18

Early and late viral proteins are classified according to their relative:

Answer 18

Time of synthesis following host infection

Question 19

One microenvironment of the skin is an area where glands produce an oily substance called:

Answer 19

Sebum

Question 20

The filamentous DNA phages are unusual, because they:

Answer 20

Are released from the host without the host being lysed

Question 21

A concatemer is a(n):

Answer 21

Combination of two or more repeated nucleotide sequences covalently linked together

Question 22

Consider a mutation in which the change is from UAC or UAU. Both codons specify the amino acid tyrosine. Which type of point mutation is this?

Answer 22

Silent mutation

Question 23

In designing a drug to inhibit pox viruses, the compound should localize in the hosts ___ to be MOST effective.

Answer 23

Cytoplasm

Question 24

Which of the following does NOT affect pathogen growth?

Answer 24

Doubling time

Question 25

A drug designed to inhibit reverse transcriptase activity would target:

Answer 25

Hepadnaviruses and retroviruses

Question 26

Pathogenicity is the ability:

Answer 26

Of the pathogen to inflict damage on the host

Question 27

Chemical mutagens, UV radiation, and ionizing radiation all increase mutation rates, but they have different mechanisms. Which type of mutagen would be best suited for creating large deletions, rearrangements, and breaking the sugar phosphate backbone within a genome?

Answer 27

Ionizing radiation

Question 28

Normal flora in the duodenum are:

Answer 28

Similar to the microflora in the stomach

Question 29

Which of the following are NOT found in the gastrointestinal tract of healthy humans?

Answer 29

Protists

Question 30

Staphylococcus aureus produces ___, leading to fibrin clots that protect them from attack by host cells.

Answer 30

Coagulase

Question 31

Hfr means high frequency of ___, and these cells are capable of transferring genes from their ___ to other cells.

Answer 31

Recombination / chromosome

Question 32

Capsules are particularly important for:

Answer 32

Protecting bacteria from host defense mechanisms

Question 33

The decrease or loss of virulence of a pathogen is referred to as:

Answer 33

Attenuation

Question 34

The spread of pathogens to the blood and lymph systems that results in a bloodborne systemic infection is called:

Answer 34

Septicemia

Question 35

Herpesviruses can cause all of the following except:

Answer 35

Spongiform encephalopathy

Question 36

Normal flora ___ colonization of pathogenic organisms.

Answer 36

Prevent

Question 37

F+ strains of Escherichia coli:

Answer 37

Have the F factor as a plasmid

Question 38

___ in saliva cleaves glycosidic linkages in peptidoglycan present in bacterial cell walls, weakening the wall and causing cell lysis.

Answer 38

Lysozyme

Question 39

Which type of viruses can be directly used for translation?

Answer 39

Positive ssRNA

Question 40

Which of the following pathogens does NOT require capsules or a slime layer for attachment?

Answer 40

Vibrio cholera