Trp Operon Concept Check (Repression)

What does the term "trp operon" refer to in molecular biology?

• A set of genes involved in the synthesis of tryptophan

• A group of genes responsible for the breakdown of tryptophan

• Genes related to the transport of tryptophan across the cell membrane

• Enzymes involved in the metabolism of tyrosine

Answer explanation

The term 'trp operon' refers to a set of genes involved in the synthesis of tryptophan.

What is the role of the trp repressor protein in the trp operon?

• It promotes transcription of the trp operon

• It inhibits transcription of the trp operon

• It enhances translation of tryptophan

• It facilitates the transport of tryptophan across the membrane

Answer explanation

The trp repressor protein inhibits transcription of the trp operon, preventing the production of tryptophan. This ensures that tryptophan is only synthesized when it is needed.

6. What happens when tryptophan levels are high in the cell?

• The trp operon is activated

• The trp operon is repressed

• Tryptophan is actively transported into the cell

• The trp repressor is inactivated

Answer explanation

When tryptophan levels are high in the cell, the trp operon is repressed. This means that the production of tryptophan is inhibited, as the cell already has enough of it.

What is the significance of the trp operon's regulatory system in terms of energy conservation?

• It ensures continuous production of tryptophan for cellular processes

• It prevents unnecessary energy expenditure by regulating tryptophan synthesis

• It promotes rapid breakdown of tryptophan to release energy

• It has no impact on energy conservation in the cell

Answer explanation

The trp operon's regulatory system prevents unnecessary energy expenditure by regulating tryptophan synthesis.

What is the role of tryptophan in the regulation of the trp operon?

• Tryptophan acts as a co-repressor

• Tryptophan acts as an inducer

• Tryptophan has no role in the regulation of the trp operon

• Tryptophan acts as an activator

Answer explanation

Tryptophan acts as a co-repressor in regulating the trp operon, inhibiting its own synthesis.

What happens to the trp operon when the trp repressor is mutated and cannot bind to tryptophan?

• The trp operon is continuously activated

• The trp operon is continuously repressed

• The trp operon is not affected

• The trp operon is intermittently activated and repressed

Answer explanation

When the trp repressor is mutated and cannot bind to tryptophan, the trp operon is continuously activated.