Which of the Following Best Explains Why E

question 8

Multiple Choice

Which of the following best explains why E. coli shuts down the trp operon if tryptophan is available in the environment?

• A) It does not shut down the trp operon, it only lowers the level of trp operon activity.
• B) The trp operon encodes genes that export tryptophan from the cell; if tryptophan already occurs in the environment, further export is not necessary.
• C) Synthesizing an amino acid takes energy, so it is a waste of energy to make something that is already available.
• D) Environmental tryptophan is of higher quality than what the E. coli can make itself.

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Definitions:

Positive Slope

In a graph, a line that goes up to the right, indicating a positive relationship or increase between two variables.

Liquidity Preference Theory

A theory that suggests interest rates are determined by the supply and demand for money, with people preferring liquidity over committing to long-term investments.

Upward Sloping

A term that describes a line or curve on a graph that shows an increase in a variable in relation to another variable as you move from left to right.

Inverse Relationship

An inverse relationship is a situation in which two variables move in opposite directions; as one increases, the other decreases.