AP Biology Unit 4 practice questions: Cell Communication and Cell Cycle
8 original multiple-choice questions on AP Bio Unit 4, cell communication and cell cycle. Answer each one in your browser and read the explanation, then review the key ideas below.
Question 1 of 8
In many signaling pathways, cyclic AMP (cAMP) acts as a
Question 2 of 8
Mitosis in a diploid cell produces
Question 3 of 8
A mutation disables the protein p53, so damaged cells pass the cell-cycle checkpoints. The most likely result is
Question 4 of 8
Steroid hormones such as testosterone usually bind to
Question 5 of 8
During which phase of the cell cycle is DNA replicated?
Question 6 of 8
Which is an example of positive feedback?
Question 7 of 8
Apoptosis is
Question 8 of 8
Cyclins and cyclin-dependent kinases (CDKs) mainly
Key ideas in Unit 4
- Cell signaling has three stages: reception, transduction and response. Second messengers such as cAMP amplify signals.
- Nonpolar signals like steroid hormones cross the membrane and bind intracellular receptors.
- Feedback: negative feedback restores a set point; positive feedback amplifies a change.
- The cell cycle is interphase (G1, S, G2) plus mitosis and cytokinesis; checkpoints, cyclins and CDKs control it.
- Apoptosis removes cells in an orderly way; failed regulation (for example, a broken p53) can lead to cancer.
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