Cycles of Cell Cycle
General Mitosis
Interphase
Cancer
100
What major events take place during the cell cycle?
Cell parts are duplicated, DNA is duplicated, cell parts and DNA are divided between the two future cells, cell divides
100
How many phases make up mitosis?
5
100
Name the molecules involved in checkpoint regulation.
cyclin, cyclin-dependent kinase (cdk), cdk inhibitor, and a target protein.
100
Cancer is caused by ______________.
Accumulation of DNA mutations.
200
What is the longest phase in the cell cycle?
Interphase
200
True or False: Cytokinesis is included in the phases of mitosis.
False
200
Why is it not a problem to break down cyclins regularly although it is needed to lift a checkpoint?
Reason 1: We need regular closing of the checkpoints
Reason 2: Even the cyclins are broken down, they can be reassembled by enzymes.
200
In the video which featured Gleevec, what was the result of the damaged DNA in a cancerous cell?
The damaged DNA resulted in a faulty mRNA. The faulty mRNA resulted in the production of a type of cdk known as tyrosine kinase which promotes the bypassing of checkpoints.
300
The cell cycle results in two genetically _________ cells.
Identical
300
Why is it risky to target telophase in chemotherapy?
During telophase, the nuclei are rebuilt. Chemotherapy can impact normal cells too so if the nucleus isn't rebuilt, the chromosomes are far more prone to damage in normal cells too.
300
Why do cyclins have a variety of molecular shapes?
Different cyclins regulate different checkpoints so the structure needs to be different in order to be sensitive to different cell conditions. Therefore, the cdk molecules will have a variety of molecular shapes.
300
Why was Gleevec an effective form of treatment for chronic myelogenous leukemia?
Gleevec contains the cdk inhibitor which blocks tyrosine kinase from binding to cyclins. Tyrosine kinase is unique to the cancerous cells.
400
Why does the S phase taking a longer time than the other portions of interphase?
The DNA double helix has to separate into separate strands, and each separate strand serves as a template for a new strand with the correct corresponding base.
400
Why is mitosis easier to observe in the root of an onion?
Growth is more extensive in the root portion of an onion plant.
400
What kind of graph (cyclin amount versus time) would you expect during the time interval just before the G1 phase ends ending at the beginning of the S phase? In the answer, y represents cyclin amount, x represents time.
400
Why are there so many immature white blood cells inside a leukemia patient?
Since the cell division is not regulated properly, there is less quality control of the cells before division occurs. Without sufficient checkpoint regulation, interphase takes less longer, mitosis and cytokinesis occurs a lot more often, resulting in more cells.
500
In addition to repairing damaged, worn, and aging cells, what is another possible function of the cell cycle?
As a form of reproduction for simple multicellular organisms.
500
Earlier in the cell cycle section, I mentioned that mitosis can be used as a form of reproduction. What is a potential disadvantage?
Mitosis produces genetically identical cells. If a major disease targeted an organism, since there is no genetic diversity, the whole population is at risk.
500
Why are higher glucose levels (up to a certain point) likely to support interphase favorably?
Glucose can be used in cellular respiration to produce ATP. ATP is broken down into ADP and P and the P binds to the target protein which signals the lifting of a checkpoint restriction.
500
In the immunotherapy portion of the cancer documentary, why were the doctors careful about strengthening the patient's immune system?
Although the doctors wanted to strengthen the patient's immune system, if they went too far, the patient's immune system could attack its own healthy cells.