1) In a metabolic pathway, a typical control mechanism is to have: ________
the final product inhibit the enzyme responsible for its own production.
the final product inhibit an early step.
a lack of reactant stimulate the pathway.
a reactant inhibit a late step.
2) Energy is stored in different forms in the body. ATP is very unstable and is put to use very quickly in cells. Other storage molecules last longer. Which gives the major energy stores of the body in the correct order?
Short term: glycogen. Medium term: glucose. Long term: fat.
Short term: fat. Medium term: glycogen. Long term: glucose.
Short term: glucose. Medium term: glycogen. Long term: fat.
3) What would be a typical regulatory system in a metabolic pathway?
The pathway's product makes it go faster, so that more and more of the product builds up in the cell or body.
The pathway's product slows it down, so that the product is maintained at a constant level in the cell or organism.
4) Which best describes body weight regulation in a normal human who is living in a modern society?
Our normal responses of appetite and metabolism ensure that adults remain at a given normal body weight. Any change from this normal weight sets in motion responses that return the body to its normal weight.
Our normal responses of appetite and metabolism tend to cause weight gain in modern societies, and they also tend to make weight loss difficult.
5) Which of the following are characteristics of metabolic pathways? (Select all that apply).
Contain many intermediates.
Are regulated.
Each pathway has a key enzyme that catalyzes most of the reactions
Are specific for each organism
Are often reversible
6) Cells or organisms tend to maintain steady internal conditions. What is the name for this property and ability of life?
Homeostasis
Adaptation
Reproduction
Metabolism
7) What is the connection between a person's genes and his or her metabolism?
DNA regulates metabolic pathways directly
enzymes encoded by genes regulate metabolic pathways
structural proteins encoded by genes regulate metabolic pathways
8) Which of the following regulatory mechanisms is described incorrectly?
feedback inhibition: product inhibits its own production
enzyme modification: enzyme gains or loses a functional group
competitive inhibitor: binds to the active site of the enzyme
All are correct
substrate availability: more substrate increases enzyme activity (until it reaches saturation)
9) How does the body react to rapid weight loss?
Hunger increases and the metabolic rate goes down.
Hunger increases and the metabolic rate goes up.
Hunger decreases and the metabolic rate goes up.