Unit 4 AP Biology

Cortisol is a hormone produced in response to stress, including starvation, in humans. Which of the following is most likely an immediate effect of a starvation-induced increase in cortisol secretion?

Increased mobilization of fatty acids from fat cells

Which of the following statements best predicts the effect of a mutation that results in a loss of the glucocorticoid receptor's ligand binding function?

The glucocorticoid receptor will remain associated with the accessory proteins.

Based on Figure 1, what percent of the time required to complete a full cycle do the cells typically spend in interphase?

95%

Based on the model of ferritin synthesis presented in Figure 2, which of the following describes the role of feedback on the control of intracellular iron levels?

An increase in iron levels activates synthesis of ferritin protein. Ferritin protein in turn binds iron, thereby decreasing both free iron levels and ferritin synthesis.

Ethylene causes fruits to ripen. In a signaling pathway, receptors activate transcription factors, which ultimately leads to ripening. Which of the following best supports the claim that ethylene initiates the signal transduction pathway that leads to ripening of fruit?

Loss-of-function mutations in ethylene receptors result in changes to the ripening process.

In mammals, an increase in the concentration of sodium in the blood triggers the release of antidiuretic hormone (ADH) from the pituitary gland. As the concentration of sodium in the blood returns to previous levels, the release of ADH from the pituitary gland is reduced. Based on the information presented, which of the following describes the most likely role of ADH in maintaining blood osmolarity?

ADH promotes an increase in the movement of water into the bloodstream

Damaged tissue releases chemicals that activate platelets and stimulate the formation of blood clots. Which of the following predictions about the activity of platelets best describes a positive feedback mechanism?

Activated platelets release chemicals that activate more platelets.

Which of the following best predicts how GSK3β mutations can lead to the development of cancer?

Cells with inactive GSK3βfail to trigger apoptosis

Which of the following best describes the role of mitosis in the cell cycle?

Distributing replicated chromosomes to daughter nuclei

A researcher claims that the epinephrine signaling pathway controls a catabolic process in muscle cells. Which of the following statements best helps justify the researcher's claim?

Glycogen phosphorylase catalyzes the conversion of glycogen to glucose-1-phosphate.

Which of the following statements accurately uses the information presented to support the hypothesis that interruption of M function in a single body cell can result in cancer?

Growth-factor signaling can trigger mitosis in cells that are in direct contact with other cells.

Based on Figure 1, which of the following statements best describes the epinephrine signaling pathway?

In involves enzymes activating other enzymes.

During mitosis, which of the following normally occurs?

Replicated chromosomes line up on the equatorial plate.

Which of the following conditions will most likely cause a normal body cell to become a cancer cell?

The environment contains mutagens that induce mutations that affect cell-cycle regulator proteins.

DNA replication occurs

during the S phase of the cell cycle

A human cell in prophase of mitosis can be distinguished from a human cell in prophase I of meiosis by the presence of

paired homologous chromosomes in the meiotic cell