Question

question 16
2.5 points
cell division is usually kept under control by.
a apoptosis.
b a single checkpoint in cytokinesis.
c several checkpoints in the cell cycle and by apoptosis.
d suicide checkpoints.
e cell cycle repair mechanisms.
question 17
2.5 points
which of the following can cause cancer?
a uv rays
b viruses
c chemicals
d all of the choices can cause cancer.
question 18
2.5 points
the type of mutation where a single letter in a sequence is changed that results in changing the codon into a stop codon and terminates the protein:
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Explanation:

• Question 16: Cell division is regulated by multiple checkpoints in the cell - cycle (G1, G2, M checkpoints) and apoptosis which can eliminate abnormal cells.
• Question 17: UV rays can cause DNA damage leading to cancer. Viruses like human papillomavirus can integrate into the host genome and cause cancer. Chemicals such as tobacco - related chemicals are known carcinogens.
• Question 18: A nonsense mutation occurs when a single - base substitution changes a codon into a stop codon, prematurely terminating protein synthesis.

Answer:

• Question 16: C. several checkpoints in the cell cycle and by apoptosis.
• Question 17: D. All of the choices can cause cancer.
• Question 18: Nonsense mutation.