In a healthy cell, which of the following proteins will be activated in order to suppress cell division if the cell is not ready or should not divide? Select one: a. p53 b. cdk c. cyclin d. seperase e. mitogen

Let us have an example, imagine that the cell is a car. For the car to work properly there are factors that need to be consider like the gas pedal and a brake pedal. If the gas pedal works normally it helps the cell to divide. But when the gas pedal gets stuck, it can cause uncontrolled cell division leads to cancer formation. How about if the brake pedal gets stuck, and the car cannot slow down, accident happens and causes cell death. Guide Questions: 1. Gas pedal that works normally and helps the cell to divide can be compare to what kind of gene? Is it oncogene, proto-oncogene or tumor suppressor gene? Explain your answer. 2. Gas pedal that gets stuck and causes uncontrolled cell division leads to cancer is what kind of gene? Is it oncogene, proto-oncogene or tumor suppressor gene? Explain your answer. 3. Brake pedal that gets stuck causes car accident and even death can be compare to what kind of gene? Is it oncogene, proto-oncogene or tumor suppressor gene? Explain your answer.

A scientist is analyzing the effects of a newly discovered cellular compound. She obtains two samples of diploid cells (2n), each with the same number of cells, and places sample 1 in a saline solution and sample 2 in a saline solution containing the newly discovered compound. She then incubates the cells for 24 hours. A bar graph of the results is shown below.   Explain how the compound most likely affected the cell’s progression through the cell cycle, and predict  the relative number of cells found in each sample when the results were observed. Support your claims with evidence from the experiment.

Overexpression of the Myc protein is a common feature of many types of cancer cells, contributing to their excessive cell growth and proliferation. By contrast, when Myc is overexpressed in most normal cells, the result is not excessive proliferation, but cell-cycle arrest or apoptosis.Which one of the following statements provides the most likely explanation for why overexpression of Myc can have such different outcomes in normal cells and in cancer cells?   A.  Normal cells contain checks and balances that prevent Myc-induced proliferation. B.  In normal cells, Myc protein acts as a mediator in cell-cycle arrest and apoptosis. C.  The target protein for Myc-induced proliferation is missing from most normal cells. D.  In normal cells, when Myc is overexpressed, the excess Myc protein precipitates.

Which of the following statements about the cell cycle is TRUE?   a. The protein APC blocks cells from entering anaphase   b. CDKs are degraded after each cell cycle phase by the addition of a ubiquitin chain to the proteins   c. A kinase is a protein that adds a ubiquitin chain to other proteins Cyclin activity is necessary, but not always sufficient, for CDK activation   d. Cyclin proteins must be degraded before Cdk proteins can be activated

Give two examples of events that can regulate the cell cycle externally.

The major stages of the cell cycle are (in order) Group of answer choices a. G, S1, M, S2 b. S1, S2, G, M c. G1, S, G2, M d. S1, M1, G, M2 e. G1, M, G2, S

List and briefly describe three major cell cycle checkpoints. For each checkpoint, predict the consequences if the checkpoint fails to work properly.

Many common medications function by interrupting the normal operation of certain signal transduction pathways. Which of the following describes a possible mechanism by which a certain medication may interrupt a signal transduction pathway? A A medication enters the target cell and triggers apoptosis by causing the release of di- gestive enzymes from cell lysosomes. B A medication interacts with the phospholipid bi-layer of the cell membrane and in- creases its permeability. с D A medication binds to membrane-bound glucose proteins and acts as an allosteric in- hibitor that prevents the intake of glucose by the cell. A medication diffuses through the membrane of a target cell and inhibits an enzyme that normally synthesizes a second messenger.

A scientist studying a group of somatic cells notices that when the cell cycle is complete, half of the daughter cells have no chromosomes and the other half have 92 chromosomes. In what phase of mitosis did an error most likely occur? Explain.