Question

1. Why is estrogen associated with carrier proteins in the blood?

A. Carrier proteins are necessary to import estrogen into cells.

B. Estrogen has only limited solubility in the bloodstream.

C. Estrogen is very unstable in the blood.

D. The carrier proteins bind with estrogen to receptors.

2. Which characteristic is NOT one attributed to a second messenger?

A. intracellular signaling molecules

B. molecules that can easily pass across membrane bilayers
C. molecules that can act as allosteric effectors for signaling proteins

D. molecules that can be rapidly converted between active and inactive forms

E. molecules that are synthesized in response to receptor/signal interactions

3. Homoserine is:
A. a precursor of both methionine and threonine.

B. a precursor of serine.
C. derived from homocysteine.
D. derived from serine.

E. derived from threonine.

Answer 1