Exam 3

Question 1

Which of the following is/are transferred to daughter cells during cell division?

Answer 1

Chromosome, proteins, and all other cellular constituents

Question 2

Which statement is true?

Answer 2

Many viruses contain their own nucleic acid polymerases

Question 3

The process by which two cells arise from one is known as:

Answer 3

Binary fission

Question 4

When packaged in the virion, the complete complex of nucleic acid and protein is known as the virus:

Answer 4

Nucleocapsid

Question 5

The time interval required for the formation of two cells from one is called the:

Answer 5

Generation time

Question 6

The term “phage” is generally reserved for the viruses that infect:

Answer 6

Bacteria

Question 7

The time between inoculation and the beginning of growth is usually called the:

Answer 7

Lag phase

Question 8

Which of the following enzymes would you expect to find in the virion of a retrovirus, but NOT in a bacteriophage?

Answer 8

Reverse transcriptase

Question 9

To determine viable cell counts of a heat-sensitive bacterial isolate, which cell counting method would be the best to avoid?

Answer 9

Pour-plate method

Question 10

Bacteria that are able to grow in humans and cause disease have likely evolved to be:

Answer 10

Mesophiles

Question 11

For bacteriophages and animal viruses ___ is the step in the viral life cycle that determines host cell or tissue specificity.

Answer 11

Attachment

Question 12

An agar plate for counting colonies and maximizing statistical validity should ideally contain:

Answer 12

30 to 300 colonies

Question 13

The packaging mechanism of T4 DNA involves cutting of DNA from:

Answer 13

DNA concameters

Question 14

The number of colonies obtained in a plate count does NOT depend of the:

Answer 14

Size of the colonies

Question 15

Cellular receptors may be composed of:

Answer 15

Combinations of proteins, carbohydrates, and/or lipids

Question 16

Many aromatic compounds used for growth substrates by bacteria are broken down during high heat autoclaving. Which is the best way to sterilize these aqueous solutions?

Answer 16

0.2 um filter sterilization

Question 17

The MOST effective antibiotics in preventing growth of disease-causing bacteria are:

Answer 17

Bacteriolytic or bacteriocidal

Question 18

What temperature is most commonly used for autoclaves to sterilize growth media and other devices prior to experimentation?

Answer 18

121C

Question 19

Most mesophilic organisms can grow in a temperature range of:

Answer 19

20-40C

Question 20

The addition of thioglycylate into a growth medium would NOT support growth of a:

Answer 20

Microaerophilic aerobe

Question 21

A microbe growing in a refrigerator is likely:

Answer 21

Psychrotolerant or psychrophilic

Question 22

How do bacteriophage influence bacterial evolution?

Answer 22

Bacteriophage transfer genetic information between bacterial cells through transduction, thus increasing the genetic diversity of bacterial evolution

Question 23

RNA virus genomes may be either:

Answer 23

Plus sense or minus sense

Question 24

How is a virion distinguished from a virus?

Answer 24

Virions are always outside the host

Question 25

A chemical that denatures proteins is MOST likely to be classified as a(n) ___ agent.

Answer 25

Bacteriocidal

Question 26

The concentration of infectious plaque forming units (pfu) per volume of fluid is known as the:

Answer 26

Titer

Question 27

Organisms able to live in environments with high sugar concentrations are:

Answer 27

Osmophiles

Question 28

Virions infecting some bacteria possess the enzyme ___ that makes a small hole in the bacterial cell wall, allowing the viral nucleic acid to enter.

Answer 28

Lysozyme

Question 29

A bacterium containing ___ provided with hydrogen peroxide will produce oxygen bubbles.

Answer 29

Catalase

Question 30

A virus that kills its host is said to be:

Answer 30

Lytic or virulent

Question 31

Retroviruses are medically important viruses because:

Answer 31

They include viruses that cause cancer and aids

Question 32

The use of ___ is the easiest and most effective way of studying many animal and plant viruses.

Answer 32

Tissue or cell culture

Question 33

Regarding the viral membrane of an enveloped virus, the lipids are derived from the ___, and the proteins are encoded by ___.

Answer 33

Host’s cell membrane / viral genes

Question 34

When solutions of host cells and infectious virions are mixed and spread on an agar plate, ___ form where viruses lyse the host cells.

Answer 34

Plaques

Question 35

Which of the following statements is true?

Answer 35

Lambda is a temperate phage that replicates its double-stranded DNA genome with a rolling circle mechanism

Question 36

Which term is most relevant in describing the efficacy of an antimicrobial for use in a clinical setting?

Answer 36

Minimum inhibitory concentration

Question 37

An antiseptic (or germicide) is distinguished from other sterilizing compounds by:

Answer 37

Being able to be used on living tissues without harm

Question 38

The consequence of an infection by a temperate bacteriophage is that the bacterial cell:

Answer 38

May lyse before it divides or may continue to divide and replicate both the virus and the cell

Question 39

A cell that allows the complete replication cycle of a virus to take place is said to be a:

Answer 39

Permissive host

Question 40

Whether lambda phage undergoes the lytic or lysogenic cycle is dependent on the accumulation of:

Answer 40

cl protein