1) A microbial siderophore is A) an effector chemical that stimulates the produc
ID: 91101 • Letter: 1
Question
1) A microbial siderophore is
A) an effector chemical that stimulates the production of iron in the environment.
B) a small molecular weight organic molecule synthesized by a microbe to bind iron in the environment.
C) a membrane protein synthesized by a microbe that transports iron from the environment.
D) any iron binding molecule synthesized by a microbe that yields a green solution when dissolved in water.
2) Fur, a protein involved in siderophore synthesis and the membrane transport of Fe-siderophore complexes, is not
A) a regulatory protein.
B) a repressor protein.
C) an activator protein.
D) a constitutively synthesized protein.
Explanation / Answer
1) A microbial siderophore is
A) not an effector chemical and do not stimulates the production of iron in the environment.
Hence, the option is incorrect.
B)a small molecular weight organic molecule synthesized by a microbe to bind iron in the environment. They are produced under low iron conditions. They chelate iron from the habitat and make them available for microbial cells.
Hence, the option(b) is correct.
C) not a membrane protein synthesised by a microbe that transports iron from the environment.
Hence, the option is incorrect.
D) not any iron binding molecule synthesised by a microbe , and do not yield a green solution when dissolved in water.
Hence, the option is incorrect.
2) Fur, a protein involved in siderophore synthesis and the membrane transport of Fe-siderophore complexes, is not
a) a regulatory protein
It is a regulatory protein that controls the concentration of iron in many bacteria.
Hence, the option is incorrect.
b) a repressor protein
It is a repressor protein. when concentration of metal is low, fur undergoes conformational change that prevents DNA binding and lifts the repression.
Hence, the option is incorrect.
c) an activator protein
Fur is not an activator protein, but contains a binding site for attachment of other activator proteins.
Hence, the option(c) is correct.
d) a constitutively synthesised protein
Fur is a constitutively synthesised protein because a mutation in the gene exhibited constitutive expression of iron uptake genes.
Hence, the option is incorrect.
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