Question

1. During which phase of the viral cycle does the genetic material from a virus become incorporated in the host's genome?

a. attachment

b. entry

c. integration

d. synthesis

e. assembly

f. release

2. You notice bacteria that your colleague has cultured shows absolutely no preference with regard to oxygen status. What term below best describes this bacteria?

a.Obligate aerobe

b.Obligate anaerobe

c.Aerotolerant anaerobe

d.Facultative anaerobe

Answer 1

1. Correct option is (c)

i. Attachment: Phage attaches to the surface of the host.

ii. Entry or penetration: is the entry of viral DNA into the host cell.

iii. Penetration: Phase DNA becomes incorporated into the host genome.

iv. Synthesis: of viral or phage genome and proteins.

v. Assembly: Viral chromosomes are surrounded by newly synthesized protective coats.

vi. Release: New viral particles are released by lysis of host wall.

2. Correct option is (c)

Obligate aerobes are the bacteria that grow only in the presence of oxygen like methanogens.

Obligate anaerobes are the bacteria that grow only in the absence of oxygen like Clostridium.

Aerotolerant anaerobes are the bacteria that have exclusively anaerobic metabolism and are insensitive to the presence of oxygen. They survive on fermentation even in the presence of oxygen like Lactobaccili.

Facultative anaerobes change their metabolism depending on the presence or absence of oxygen. If oxygen is present, they use more efficient process of respiration.If oxygen is absent, they use fermentation process like E.coli.