Genetics : Cell Division

Study concepts, example questions & explanations for Genetics

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Example Questions

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Example Question #31 : Cell Division

Mutations in genes encoding cell cycle regulatory components may contribute to all of the following except __________?

Possible Answers:

cancer

loss of cycle control

proto oncogene

genomic instability

Correct answer:

proto oncogene

Explanation:

Mutations can lead to lack of regulation, which overall, leads to genomic instability providing opportunities for uncontrolled growth — for example, cancer from the loss of cell cycle control. Proto oncogenes are normal genes that promote and regulate cell growth. Mutations to the proto oncogene itself could lead to oncogenes, which are cancer promoting.

Example Question #32 : Cell Division

A __________ is a normal gene that promotes regulated cell growth and proliferation, while a __________ is a mutated or over expressed gene that promotes cancer.

Possible Answers:

carcinogen, mutagen

mutagen, carcinogen

oncogene, proto oncogene

proto oncogene, oncogene

Correct answer:

proto oncogene, oncogene

Explanation:

Proto oncogenes promote proteins via proliferation with regulation. Oncogenes promote cell proliferation without regulation, leading to genomic instability, which can lead to cancer. A mutagen is a physical or chemical substance that can increase the frequency of mutations. A carcinogen is a substance that is directly involved in causing cancer.

Example Question #33 : Cell Division

p53 is a famous __________, which aids in blocking cell cycle progression and preventing cancer.

Possible Answers:

checkpoint

proto oncogene

tumor suppressor 

oncogene

Correct answer:

tumor suppressor 

Explanation:

p53 is a famous tumor suppressor, which blocks cell cycle progression preventing damaged/mutated DNA from being duplicated. Proto oncogenes are normal genes that regulate cell growth and proliferation. Oncogenes are mutated proto oncogenes that lead to unregulated cell proliferation. The checkpoints are in the S, G1, G2/M phases.

Example Question #34 : Cell Division

Which of the following describes a centromere?

Possible Answers:

the center of a daughter cell after mitosis

the center of an individual chromosome

the last stage of cell division 

the fiber spindle connecting individual chromosomes during mitosis

Correct answer:

the fiber spindle connecting individual chromosomes during mitosis

Explanation:

The correct answer here is the fiber connecting the chromosomes in the initial stages of mitosis. Remember that during mitosis, 1 pair of chromosomes becomes 2 new pairs. This requires the pair to split initially, duplicate, then break off into the new cells. The last stage of cell division is called anaphase, not a centromere. A centromere is the middle of a pair of chromosomes, not the individual chromosome. If you chose the daughter cell, remember that centromeres are not describing the new cell itself, but the connection between chromosomes inside the cell. 

Example Question #31 : Cell Division

How are gametes produced?

Possible Answers:

RNA replication

mitosis

crossing over

meisosis

Correct answer:

meisosis

Explanation:

The correct answer here is meiosis. Some of the options look challenging because you could assume RNA or DNA replication would result in gametes. However, the term gamete singularly refers to a sex-germ cell that is the direct result of meiosis. We can cancel out mitosis because that is specifically to replicate non sex related cells. 

Example Question #35 : Cell Division

What best describes spindle fibers?

Possible Answers:

act as the primer in RNA creation 

the fibers that help move/rearrange chromosomes during the later stages of mitosis

 

only present during mieosis, not mitosis

connect individual chromosomes to make a pair

Correct answer:

the fibers that help move/rearrange chromosomes during the later stages of mitosis

 

Explanation:

The correct answer is that they are the fibers that help move the chromosomes towards a certain side of the cell during mitosis. If you chose the option about connecting a pair of chromosomes, remember that this is called a centromere and is also vital in mitosis. If you chose that the spindle fibers are only necessary in meiosis, remember that even in mitosis, fibers are needed to separate the individual chromosomes to form a new cell. Fibers do not act as the primer in RNA production  

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