How do some cyanobacteria fix nitrogen while growing aerobically?

How do some cyanobacteria fix nitrogen while growing aerobically?

a. they don't because nitrogenase is destroyed by oxygen
b. by using special cells called heterocysts that protect the enzyme
c. by using cysts that protect the enzyme
d. they just do it, no special structures or mechanisms
e. they live symbiotically with other organisms that protect the enzyme


Answer: by using special cells called heterocysts that protect the enzyme

Some bacteria form environmentally resistant forms called __________.

Some bacteria form environmentally resistant forms called __________.

a. endospores
b. heterocysts
c. colonies
d. hyphae
e. actinomycetes


Answer: Endospores

Which of the following genera does NOT undergo differentiation?

Which of the following genera does NOT undergo differentiation?

a. Anabaena
b. Bacillus
c. Clostridium
d. Escherichia
e. Streptomyces


Answer: Escherichia

During biofilm formation, as more and more cells bind to the surface, they begin sending signals to each other in a process called

During biofilm formation, as more and more cells bind to the surface, they begin sending signals to each other in a process called

a. quorum sensing
b. homoserine lactone
c. siderophores
d. polysaccharides
e. symbiosis


Answer: Quorum sensing

Which of the following is true of all biofilms?

Which of the following is true of all biofilms?

a. They only contain a single species.
b. The EPS may be protein or polysaccharide.
c. Cells in the biofilm are dormant until the bacteria leave the biofilm.
d. The EPS is secreted by the bacteria.
e. It is a continuous monolayer surface deposit.


Answer: The EPS is secreted by the bacteria

Eukaryotic microorganisms enter the __________ phase at much lower cell numbers than bacteria simply because they are bigger than bacteria.

Eukaryotic microorganisms enter the __________ phase at much lower cell numbers than bacteria simply because they are bigger than bacteria.

a. lag
b. exponential
c. stationary
d. death
e. log


Answer: Stationary