Question 1

Which of the following would NOT lead to cancer?

Accepted Answer

An active proto-oncogene is normal and necessary for regular cell function and growth. It only leads to cancer when it becomes mutated or overly active, at which point it is referred to as an oncogene.

Question 2

When would you need a gene that can stop the cell cycle?

Accepted Answer

A gene that can stop the cell cycle is necessary when a mutation has occurred and the cell needs time to repair it before continuing (A), and when there is no immediate need for more cells (B). This allows the cell to avoid passing on mutations and to regulate its growth according to the organism's needs.

Question 3

What is the difference between mutagens and carcinogens?

Accepted Answer

Not all mutagens cause cancer, but all carcinogens have the potential to cause cancer. Carcinogens are substances that damage DNA and can result in cancer. Mutagens, on the other hand, are agents that cause mutations in DNA, but not all mutations result in cancer. Therefore, B is incorrect (not all carcinogens are mutagens), and A and E are also incorrect. C is partially correct but lacks the distinction between mutagens and carcinogens. So, option D is the correct answer.

Question 4

A proto-oncogene is a gene that

Accepted Answer

A proto-oncogene is a gene that regulates normal cell division by telling the cell when to go through the cell cycle. When mutated, it can become an oncogene, causing the cell to divide uncontrollably and potentially leading to cancer.

Question 5

A mutation in one cancer-related gene is not enough to cause a cell to become cancerous.Why?

Accepted Answer

Cell division is a complex process that relies on multiple proteins and pathways to ensure accurate replication and division. Therefore, a mutation in one cancer-related gene may not be enough to disrupt this balance and cause cancer.

Question 6

What would happen if a proto-oncogene,such as Her2,were mutated?

Accepted Answer

When a proto-oncogene such as Her2 is mutated, it may become an oncogene which can cause cells to divide uncontrollably or continue through the cell cycle without properly stopping at checkpoints. This can result in uncontrolled cell growth and potentially lead to the development of cancer. Option A is not directly related to the mutation of a proto-oncogene, while option C is the opposite of what would happen in the case of an oncogene mutation. Option D is partially correct, but option B is the most accurate and specific.

Question 7

Tumor-suppressor genes can act by making proteins that

Accepted Answer

Tumor-suppressor genes can act by making proteins that repair damaged DNA, stop the cell from dividing when there are problems, induce apoptosis, and cause cell death. Therefore, all of the above choices are correct.

Question 8

What would happen if a tumor suppressor,such as BRCA1,was mutated?

Accepted Answer

If a tumor suppressor like BRCA1 is mutated, it can lead to the inability for DNA to be repaired and it can also allow for the cell cycle to continue without stopping when needed. Therefore, choices A and B are correct. Choice C is not correct because cells would not stop dividing, but rather they may divide uncontrollably leading to the development of tumors. Therefore, the correct answer is D.

Question 9

Permanent activation or overexpression of proto-oncogenes

Accepted Answer

Proto-oncogenes, when permanently activated or overexpressed, can lead to cancer, including breast cancer, by promoting uncontrolled cell division.

Question 10

You isolate cells from a tumor and study them.You observe that the cells continue dividing,even when DNA is damaged,when the cells become crowded,or even when nutrients run low.These observations lead you to suspect that the cells

Accepted Answer

The answer of You isolate cells from a tumor and...

Question 11

Which set of mutations in a cell would you expect to be LEAST tumorigenic?

Accepted Answer

BRCA1 mutations alone are associated with an increased risk of breast and ovarian cancers but are not considered as tumorigenic as mutations affecting multiple tumor suppressor genes such as BRCA1, BRCA2, Her2, and p53 or the combination of BRCA1, BRCA2, and p53 mutations, which are associated with higher cancer risks. The addition of Her2 mutation further increases the risk.

Question 12

BRCA1 and BRCA2 are ___________,p53 is a ___________,and Her2 is a __________.

Accepted Answer

BRCA1 and BRCA2 are tumor-suppressor genes that help repair DNA and suppress tumors. p53 is also a tumor-suppressor gene that plays a crucial role in preventing cancer by repairing DNA or inducing apoptosis. Her2 is a proto-oncogene that can promote cell growth, and when overexpressed, can lead to cancer.

Question 13

Why does cancer affect older individuals more frequently than younger people?

Accepted Answer

Cancer is caused by mutations in genes that control cell growth and division. The longer a person lives, the more opportunities there are for mutations to accumulate in their DNA, either from exposure to environmental factors such as radiation or chemicals, or simply from errors that occur during DNA replication. Therefore, older people have had more time to accumulate mutations from various sources, making them more susceptible to developing cancer.

Question 14

Mutations that cause the cell to divide rapidly,even in the absence of a signal to divide,are usually mutations of

Accepted Answer

Mutations of proto-oncogenes can lead to the overproduction or overactivity of growth-promoting proteins, causing the cell to divide rapidly even without a signal to do so.

Question 15

Predict what would most likely happen in a cell if BRCA1 were mutated.

Accepted Answer

BRCA1 is a tumor suppressor gene that helps repair DNA damage and prevent the development of cancer. When it is mutated, the cell's ability to repair DNA damage is impaired, which increases the likelihood of DNA errors occurring more frequently. This can eventually lead to the development of cancer.

Question 16

Which of the following steps (in order)would most likely lead to tumor formation?

Accepted Answer

The inherited mutated tumor-suppressor gene sets the stage for further mutations in proto-oncogenes. These mutations can turn proto-oncogenes into oncogenes, which promote uncontrolled cell division and can lead to tumor formation. The cell then rapidly divides and spreads, which is the final step in tumor formation.

Question 17

True or False: To get cancer,all you need is a mutation in one essential gene.

Accepted Answer

Cancer is a complex disease that involves multiple genetic mutations and environmental factors. It is not enough to have just one mutation in an essential gene to develop cancer. Multiple mutations are required for cancerous cells to form and multiply.

Question 18

In normal cells,lack of functional tumor suppressors would cause

Accepted Answer

Tumor suppressors are proteins that regulate cell division, repair DNA mistakes, or tell cells when to die (a process known as apoptosis). When these proteins are absent or non-functional, cells can divide uncontrollably, damaged cells can continue to divide, mutations can accumulate, and cancer can develop.

Question 19

A tumor suppressor gene is a gene that

Accepted Answer

A tumor suppressor gene is a gene that tells the cell when to stop the cell cycle. When these genes are mutated or lost, cells may continue to divide uncontrollably and form tumors. Examples of tumor suppressor genes include p53 and RB1.

Question 20

Apoptosis can be described as

Accepted Answer

Apoptosis is a process of programmed cell death that is crucial for tissue homeostasis, development, and the elimination of damaged or potentially harmful cells.

Quiz 10: Mutations and Cancer