Cell Biology Chapter 20

Which type of junction involves a connection to the actin cytoskeleton?

adherens junctions

Hemidesmosomes are important for...

attaching epithelial cells to the extracellular matrix.

Which of the following statements about cancer is FALSE?

A mutation in even a single cancer-critical gene is sufficient to convert a normal cell into a cancer cell.

Which of the following types of mutation would convert a photo-oncogene into a oncogene?

A mutation that greatly increases the amount of the proto-oncogene protein.

Which of the following genetic changes cannot convert a photo-oncogene into an oncogene?

A mutation that introduces a stop codon immediately after the codon for the initiator methionine.

Which of the following statements about tumor suppressor genes is FALSE?

Cells with one functional copy of a tumor suppressor gene will usually proliferate faster than normal cells.

Which of the following statements about collagen is FALSE?

Collagen synthase organizes the mature collagen molecules into ordered collagen fibrils.

A genetic test to detect predisposition to cancer would likely examine the APC gene for involvement in which types of cancer?

Colorectal only.

A metastasis is...

a secondary tumor in a different part of the body that arises from a cell from the primary tumor.

induced pluripotent stem cells (iPS)...

can be created by the expression of a set of key genes in most somatic cell types, including cells derived from adult tissues.

An adult hemopoietic stem cell found in the bone marrow...

can undergo self-renewing division for the lifetime of a healthy animal.

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

excessive cell division

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

excessive cell division

A cell can crawl through a tissue because of the transmembrane ___ proteins that can bind to fibronectin outside of the cell.

integrin

A basal lamina...

is a thin layer of extracellular matrix underlying an epithelium.

A malignant tumor is more dangerous than a benign tumor because...

its cells invade other tissues.

Plasmodesmata...

permit small molecules to pass from one cell to another.

When a terminally differentiated cell in an adult body dies, it can typically be replaced in the body by a stock of...

proliferating precursor cells.

Ras is a GTP-binding protein that is often defective in cancer cells. A common mutation found in cancer cells causes Ras to behave as though it were bound to GTP all the time, which will cause cells to divide inappropriately. From this description, the normal Ras gene is _______. (a) a tumor suppressor. (b) an oncogene. (c) a proto-oncogene. (d) a gain-of-function mutation.

proto-oncogene

Which type of junctions contributes the most to the polarization of epithelial cells?

tight junctions

Both multicellular plants and animals have...

tissues composed of multiple different cell types.

The artificial introduction of three key ___ into an adult cell can convert the adult cell into a cell with the properties of ES cells.

transcription factors

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

Genes involved in control of the cell cycle.

Which of the following statements about interns is FALSE?

Integrins use adaptor proteins to interact with the microtubule cytoskeleton.

Which of the following function does the product of the normal p53 gene carry out?

It inhibits the cell cycle.

Which of the following statements is FALSE?

Proteoglycans are a major component of compact connective tissues but are relatively unimportant in watery tissues such as the jellylike substance in the interior the eye.

Which of the following is NOT an example of a connective tissue?

The layer of photoreceptors in the eye.

Why are BRCA1 and BRCA2 considered to be tumor-suppressor genes?

Their normal products participate in repair of DNA damage.

Which of the following statements correctly describes a characteristic of tumor-suppressor genes?

They encode proteins that help prevent uncontrolled cell growth.

Which of the following processes do normal protocols-oncogenes exhibit?

They stimulate normal cell growth and division.