Epidermal growth factor (EGF) signals through a receptor, tyrosine kinase. EGF signaling promotes cell division by increasing nuclear concentrations of CyclinD through both the MEK and AKT signaling pathways as shown in the diagram. Use the EGF Pathway passage to answer the questions.

1. Which of these BEST describes how the signal is transduced from the EGF receptor to the Ras protein?
A.
Ras is phosphorylated.
B.
Ras is dephosphorylated.
C.
Ras binds to a GTP molecule.
D.
Ras hydrolyzes a GTP molecule.

2. High concentrations of nuclear CyclinD is required for entry into S phase. Which of these events MOST likely occur upon entry into S phase?
A.
CyclinD is synthesized.
B.
CyclinD is degraded.
C.
DNA is polymerized.
D.
DNA is depolymerized.

3. A drug that inhibits the kinase activity of AKT would MOST likely have which of the following effects?
A.
Increased GSK-3b activity and increased CyclinD synthesis.
B.
Increased GSK-3b activity and decreased CyclinD synthesis.
C.
Decreased GSK-3b activity and increased CyclinD synthesis.
D.
Decreased GSK-3b activity and decreased CyclinD synthesis.