1: Which statement is not true: a) Nitrogen gas is fixed by free-living bacteria
ID: 85004 • Letter: 1
Question
1: Which statement is not true:
a) Nitrogen gas is fixed by free-living bacteria and those living as endosymbionts in the roots of plants.
b) Denitrification is converting amonia to nitrates.
c) Most available nitrogen is in inorganic forms.
d) Nitrogen is a major component of proteins and nucleic acids.
2: True or False: Operational genes tend to be transferred vertically.
3: Bacteria can respond by producing small molecules such as cAMP and ppGpp to the stress of:
a) extreme alkaline conditions.
b) absence of oxygen.
c) starvation.
d) osmotic stress.
4: Which of the following is true of viruses:
a) they contain both RNA and DNA.
b) they are the only microbial type of organism that requires a host cell.
c) their genome is protected by S-layer.
d) they can infect all types of cells.
e) none of the above.
5: Transposable elements differ from plasmids in that only plasmids:
a) may code for antibiotic resistance.
b) consist of double stranded DNA.
c) may exist autonomously, not intregated into host cell.
d) may be transmitted horizontally from one bacterium to another.
6: Name key cells that govern the primary or secondary responses:
a) the cells first detecting antigens:
b) the cells activating antibody generating cells:
c) the cells generating antibodies:
d) the cells remaining in the body after the primary response and being reactivated at the secondary response:
Explanation / Answer
Que 1.
Ans:
The statement which is not true: b) Denitrification is converting ammonia to nitrates.
Explanation:
- The biological reduction of nitrate to nitrogen gas by facultative heterotrophic bacteria is called Denitrification.
- The biological conversion of ammonium to nitrate nitrogen is called Nitrification.
Que 2.
Ans:
Operational genes tend to be transferred vertically: False.
Explanation:
- Operational genes tend to be transferred horizontally.
- The horizontal transfer of operational genes is a continual process in prokaryotes.
Que 3.
Ans:
Bacteria can respond by producing small molecules such as cAMP and ppGpp to the stress of: c) Starvation.
Explanation:
- Bacteria use an array of sensory systems to moniter their environment to enable adaptation to stressful conditions.
- Bacteria can respond by producing small molecules such as cAMP and ppGpp to the stress of nutrient deprivation i.e. starvation.
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