Question

Some species of bacteria can either synthesize the amino acid glycine or absorb it from their surroundings. If glycine binds to a repressor protein, which then allows the repressor to bind to the bacterial chromosome, the operon will not be transcribed. If it is like other operons, the presence of glycine will result in the _____.

a) Repression of the operon
b) Activation of the operon
c) Induction of the operon
d) Termination of the operon

Answer 1

The presence of glycine, which binds to a repressor protein and enables it to bind to the bacterial chromosome, resulting in repressing transcription, indicates that the operon is repressible. The correct option is a.

Step-by-step explanation:

If glycine binds to a repressor protein, which then allows the repressor to bind to the bacterial chromosome and prevent transcription of the operon, this scenario is characteristic of a repressible operon.

Repressible operons typically contain genes encoding enzymes required for biosynthetic pathways and are regulated through the binding of repressors to operator regions. In this case, when glycine is present and binds to the repressor, it causes the operon to be switched off, hence the presence of glycine will result in the repression of the operon.

Therefore, the correct option is a.