Question 1

Muscle cells differ from nerve cells mainly because they

Accepted Answer

Muscle cells and nerve cells both contain the same genetic information, but they differ in which genes they express. This is due to differences in regulation of gene expression, rather than differences in the genes themselves.

Question 2

Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror-image duplication of posterior parts. This is evidence that the product of the bicoid gene

Accepted Answer

The absence of bicoid mRNA results in the absence of anterior larval body parts and mirror-image duplication of posterior parts, indicating that the product of the bicoid gene normally leads to the formation of head structures.

Question 3

In colorectal cancer, several genes must be mutated in order to contribute to a cell developing into a cancer cell, supporting Knudsen's hypothesis. Which of the following kinds of genes would you expect to be mutated?

Accepted Answer

Genes involved in the control of the cell cycle are critical for preventing cells from dividing uncontrollably, which is a hallmark of cancer. Mutations in these genes can allow cells to bypass normal checkpoints and continue dividing, contributing to the development of colorectal cancer.

Question 4

The cancer-causing forms of the Ras protein are involved in which of the following processes?

Accepted Answer

Ras proteins are involved in relaying signals from growth factor receptors to the nucleus, which influences cell growth and division. Mutations in Ras can lead to uncontrolled cell growth and cancer.

Question 5

Which of the following is characteristic of the product of the p53 gene?

Accepted Answer

The answer of Which of the following is characteristic of...

Question 6

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Accepted Answer

Proto-oncogenes normally help regulate cell division, but if they mutate or become overactive, they can turn into oncogenes that promote uncontrolled cell growth and division leading to cancer.

Question 7

In animals, embryonic stem cells differ from adult stem cells in that

Accepted Answer

Embryonic stem cells have the ability to differentiate into more cell types than adult stem cells. This is because embryonic stem cells have not yet undergone specialization into specific cell types, while adult stem cells have already committed to a specific lineage. Therefore, embryonic stem cells have greater potential for differentiation and are considered more versatile than adult stem cells.

Question 8

Which of the following statements describes proto-oncogenes?

Accepted Answer

Proto-oncogenes are normal genes that encode proteins that promote cell growth and division. However, if mutated or expressed at high levels, they can become oncogenes and contribute to cancer development.

Question 9

Cell differentiation always involves

Accepted Answer

Cell differentiation involves the production of tissue-specific proteins such as muscle actin. This is essential for cells to carry out specific functions in different tissues and organs of the body. The other options (B, C, D, and E) may be involved in some form of cell differentiation but are not always necessary.

Question 10

Apoptosis involves all but which of the following?

Accepted Answer

Apoptosis does not involve lysis of the cell. Instead, it is a controlled process of programmed cell death. The other options are all potential components of apoptosis.

Question 11

Tumor-suppressor genes

Accepted Answer

Tumor-suppressor genes can encode proteins that promote DNA repair or cell-cell adhesion, which helps prevent the development of cancer. They are not overexpressed in cancerous cells, are not cancer-causing genes, and do not stimulate the cell cycle.

Question 12

BRCA1 and BRCA2 are considered to be tumor-suppressor genes because

Accepted Answer

BRCA1 and BRCA2 are tumor-suppressor genes because their normal products participate in repair of DNA damage. Mutations in these genes can result in a loss of this repair function, leading to an increased risk of developing breast, ovarian, and other types of cancer.

Question 13

Forms of the Ras protein found in tumors usually cause which of the following?

Accepted Answer

Forms of the Ras protein found in tumors usually cause growth factor signaling to be hyperactive, leading to uncontrolled cell division and tumor growth.

Question 14

A genetic test to detect predisposition to cancer would likely examine the APC gene for involvement in which type(s) of cancer?

Accepted Answer

The APC gene is most commonly associated with inherited predisposition to colorectal cancer. Mutations in this gene can also increase the risk for other cancers such as stomach, small intestinal, and pancreatic cancer, but these are less commonly linked to APC mutations compared to colorectal cancer.

Quiz 16: Development, Stem Cells, and Cancer