Module 1- Metabolic pathways are regulated in three principal ways

Question 1

what is regulation of pathways important for

Answer 1

to ensure efficient use of fuels and to be sure that biosynthetic processes are coordentated

Question 2

what are the three ways in which a metabolic pathway can be regulated

Answer 2

-the amount or abundance of an enzyme that catalyzes a regulated step in a pathway can be regulated
-the catalytic activity of the enzyme can be regulated
-controlling the availability of a substrate

Question 3

how can the amount or abundance of an enzyme that catalyzes a regulated step in a pathway can be regulated

Answer 3

since the enzymes are proteins and thus coded for by genes the amount of an enzyme in a cell could be controlled by affecting the expression of the gene that codes for it

Question 4

how can the catalytic activity of the enzyme can be regulated

Answer 4

in two ways:
-allosteric regulation involves binding of inhibitors or activators to the enzyme that will either decrease or increase the activity of the enzyme
-enzymes can also be covalently modified in response to hormones and other signals that can lead to a change in the activity of the enzyme

Question 5

how can controlling the availability of a substrate regulate the pathway

Answer 5

ex. fatty acid breakdown occurs inside the mitochondria, which means that fatty acids that are present in the cytosol need to be transported into the mitochondria before that can be degraded, thus the rate of fatty acid break down is controlled in part by regulating the rate at which fatty acids are transported to the mitochondria