Chapter 13 Assignment
1. The trp operon consists of ________ genes that encode tryptophan biosynthesis
enzymes.
a. Five
2. In the absence of tryptophan, the trp repressor is
a. inactive and cannot bind to the operator.
3. An operon is a group of genes that are all transcribed together, which is under the control
of single operator site.
a. True
4. The lac operon is expressed when lactose is
a. Present.
5. When lactose is present,
a. It is converted to a molecule that binds to the repressor, preventing it from
binding the operator site.
6. In the absence of lactose, the lac repressor is
a. active and can bind to the operator.
7. Operons can best be described as
a. groups of genes within prokaryotes that share a common function.
8. If the repressor protein does NOT bind to the operator region of the operon, which of the
following will occur?
a. The RNA polymerase enzyme WILL be able to bind, transcription WILL occur, and
enzymes for breaking down lactose WILL be produced.
9. How specifically does lactose allow for an increase in transcription?
1. The trp operon consists of ________ genes that encode tryptophan biosynthesis
enzymes.
a. Five
2. In the absence of tryptophan, the trp repressor is
a. inactive and cannot bind to the operator.
3. An operon is a group of genes that are all transcribed together, which is under the control
of single operator site.
a. True
4. The lac operon is expressed when lactose is
a. Present.
5. When lactose is present,
a. It is converted to a molecule that binds to the repressor, preventing it from
binding the operator site.
6. In the absence of lactose, the lac repressor is
a. active and can bind to the operator.
7. Operons can best be described as
a. groups of genes within prokaryotes that share a common function.
8. If the repressor protein does NOT bind to the operator region of the operon, which of the
following will occur?
a. The RNA polymerase enzyme WILL be able to bind, transcription WILL occur, and
enzymes for breaking down lactose WILL be produced.
9. How specifically does lactose allow for an increase in transcription?
