AP BIO Cell Cycle and Signaling Test review

Figure 1. The average amount of time spent by a particular type of eukaryotic cell in each phase of the cell cycle Based on Figure 1, what percent of the time required to complete a full cycle do the cells typically spend in interphase? A) 5% percent B) 35% percent C) 50% percent D) 95% percent

D) 95% percent

Researchers studying cell cycle regulation in budding yeast have observed that a mutation in the CDC15 gene causes cell cycle arrest in telophase when the yeast cells are incubated at an elevated temperature. Which of the following statements best predicts the effect of the cell cycle arrest on proliferating yeast cells? A) The yeast cells will transition out of G0 but will fail to complete the G1 phase B) The yeast cells will initiate mitosis but will fail to complete the G2 phase. C) The yeast cells will replicate their chromosomes but will fail to complete cytokinesis. D) The yeast cells will replicate their organelles but will fail to complete the S phase.

C) The yeast cells will replicate their chromosomes but will fail to complete cytokinesis.

Glycogen synthetase kinase 3 beta is a protein kinase that has been implicated in many types of cancer. Depending on the cell type, the gene for glycogen synthetase kinase 3 beta (GSK3β)can act either as an oncogene or as a tumor suppressor. Which of the following best predicts how GSK3β mutations can lead to the development of cancer? A) Cells with inactive GSK3β fail to trigger apoptosis. B) Cells with inactive GSK3β fail to proceed past the G2/M checkpoint. C)Cells with overactive GSK3β are more likely to repair DNA damage. D)Cells with overactive GSK3β have longer cell cycles.

D)Cells with overactive GSK3β have longer cell cycles.

A group of researchers cultured yeast cells in a nutrient-rich environment and a nutrient-poor environment and observed the duration of the stages of their cell cycles. The results of their study are summarized in Table 1. The cell cycle of yeast cells grown in the nutrient-poor environment is approximately what percent of the cell cycle of yeast cells grown in the nutrient-rich environment? a) 168 b) 127 c) 179 d) 160

a) 168

Cancer cells behave differently than normal body cells. For example, they ignore signals that tell them to stop dividing. Which of the following conditions will most likely cause a normal body cell to become a cancer cell? a) The environment already contains cancer cells. b) The environment has an abundance of nutrients. c) The environment lacks signals that would otherwise tell the cell to stop dividing. d) The environment contains mutagens that induce mutations that affect cell-cycle regulator proteins.

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