Question

Consider a biochemical pathway with five steps that lead to the production of product Q. If there is an abundance of product Q, the most efficient way to slow down the entire pathway would be to regulate ________?

1) the first enzyme in the pathway
2) the last enzyme in the pathway
3) every enzyme in the pathway

Answer 1

The most efficient way to slow down a biochemical pathway with excess product is to regulate the first enzyme through feedback inhibition, which prevents waste of resources and energy in the cell.

Step-by-step explanation:

If there is an abundance of product Q in a biochemical pathway with five steps, the most efficient way to slow down the entire pathway would be to regulate the first enzyme in the pathway. This method is known as feedback inhibition, where the accumulated end product (substance Q) inhibits the activity of an upstream enzyme, often the first in the pathway. This binding of the end product to the first enzyme causes an allosteric change, which inhibits catalysis, effectively reducing the throughput of the entire pathway. This regulatory mechanism ensures that the pathway does not waste resources by producing more of the product than the cell requires. Furthermore, allosteric regulation ensures that if the final product is not needed, the entire pathway is efficiently slowed down or stopped to conserve energy.