chapter 19

Of the offspring that result from the reproductive cloning of mammals by somatic nuclear transfer, _______% are viable.

1-2

Humans possess about _______ different cell types.

200

Which products would result from caspase cleavage of a protein with the amino acid sequence AVEELCSTWYYDLLCHMRTL?

AVEELCSTWYYD + LLCHMRTL

An apoptosome is a complex containing multiple subunits of

Apaf-1, caspase-9, and cytochrome c

Which of the following signaling pathways is not important to stem cell physiology?

Bax

Most cells in adult animals are in the _______ stage of the cell cycle.

G0

Which of the following diseases would not be an ideal target for therapeutic cloning?

HIV

Which of the following is not phosphorylated by Akt?

PI 3-kinase

A major pathway that signals cell survival and inhibits cell death is the _______ pathway.

PI 3-kinase/Akt

Which of the following are the three core transcription factors that can reprogram adult somatic cells into induced pluripotent cells?

Sox2, Oct4, and Nanog

The PI 3-kinase pathway is important in countering apoptosis in healthy cells and promotes cell survival. Which statement about the PI 3-kinase pathway is false?

activated Akt phosphorylates and activates Bad

Hematopoietic stem cells can give rise to

all blood cells and macrophages

A hematopoietic stem cell may give rise to which of the following differentiated cells?

all of the above

Bone marrow transplants are used to treat patients with

all of the above

Effector caspases cleave

all of the above

Which of the following adult cell types is arrested in G 0?

all of the above

TNF and related cytokines can directly induce apoptosis. Which statement about TNF-mediated induction of apoptosis is true?

all of the above statements are true

The distinct series of changes that characterizes programmed cell death is called

apoptosis

Intestinal epithelial stem cells are located _______ the crypt.

at the bottom of

Which of the following transcription factors has the potential to act as an oncogene, resulting in a high risk of cancer?

c-Myc

The gene ced-3 of C. elegans codes for a proteolytic enzyme that is a

caspase

Which of the following events is not associated with apoptosis?

cell cycle re-entry

VEGF is secreted by

cells deprived of oxygen

Many stimuli that trigger cell death release the molecule _______ from the intermembrane space of mitochondria so they can bind to Apaf-1.

cytochrome c

Which of the following is not a key property of stem cells in tissues?

dividing within each tissue to maintain a set number of cells

Members of the Bcl-2 family of proteins are

either antiapoptotic or proapoptotic

Which of the following stem cells can give rise to all the differentiated cell types of adult organisms?

embryonic stem cells

Each of the three cell types in the adult intestinal epithelium is derived from a different stem cell.

false

Injured muscle cells regenerate by division of muscle fibers to form myoblasts that proliferate and fuse to form new muscle fibers.

false

Liver cell injury induces proliferation of liver stem cells.

false

Apoptotic cells produce "eat me" signals, which include _______ of cell surface _______.

gain; phosphatidylserines

Using approaches similar to those of Takahashi and Yamanaka, scientists have now reprogrammed adult fibroblasts to become

heart muscle cells

Ced-9 functions directly to

inhibit Ced-4

Cells that die as the result of acute injury undergo

lysis

Which of the following events is not part of apoptosis?

lysis of cell fragments and release of their contents

During development, 50% of neurons die; those that survive are those that

made correct connections with their target cells

In 2006, Takahashi and Yamanaka demonstrated that somatic cells can be reprogrammed or converted into induced pluripotent stem cells. Subsequent studies in _______ showed that these cells, like embryonic stem cells, are capable of differentiating into virtually all cells.

mice

Some differentiated cells retain the ability to proliferate as needed to repair damaged tissue throughout the life of the organism. Which of the following cell types do not retain this unique ability?

neurons

Bax and Bak act by

oligomerizing in the mitochondrial outer membrane, forming pores that release cytochrome c

The following represents a signal transduction cascade initiated by double-stranded DNA damage and ending with activation of apoptosis by the BH3-only proteins PUMA and Noxa. Double-stranded DNA damage; Chk2; _______; PUMA/Noxa; apoptosis. Which protein belongs in the blank?

p53

The key protein involved in "deciding" whether a cell with DNA damage should delay its cell cycle or undergo apoptosis is

p53

In adult organisms, cell death must be balanced by cell

renewal

The stem cells of skeletal muscle are called

satellite cells

Which statement about stem cells is false?

stem cells in organs can only differentiate into the tissue in which they are located

Which statement about cloning by somatic cell nuclear transfer is false?

the cloned embryo is genetically identical to the foster mother

Mammalian embryonic stem cells are cultured from cells taken from

the inner cell mass

What is the best rationale for the use of therapeutic cloning to replace defective cells or tissues in a patient?

the transplanted cells are identical to those of the recipient who donated the adult nucleus, so complications of immune rejection are avoided

Which statement about caspases is false?

they predominantly break up Golgi membranes, which releases other capsases to cleave nuclear lamins and cytoskeleton proteins

Early experiments by Takahashi and Yamanaka showed that a set of four genes introduced by retroviral expression are capable of transforming somatic cells into induced pluripotent stem cells. The four proteins encoded by these genes were all

transcription factors

The reprogramming of somatic cells into other types of differentiated cells (other than induced pluripotent stem cells) is referred to as

transdifferentiation

Intestinal stem cells may give rise to all of the following terminally differentiated cell types in the intestinal epithelium except _______ cells.

transit-amplifying

When stem cells of the intestinal epithelium and epidermis divide, they give rise to two different cells: one stem cell and one _______ cell.

transit-amplifying

A mutant bcl-2 gene can be an oncogene.

true

As a causal factor in the development of tumors, the inability of cancer cells to undergo apoptosis is as significant as their uncontrolled proliferation.

true

Goblet cells and enteroendocrine cells have the same stem cells as absorptive epithelial cells.

true

If reintroduced into early embryos, embryonic stem cells can give rise to cells in all tissues of a mouse.

true

In normal, nonapoptotic cells, antiapoptotic members of the Bcl-2 protein family bind to proapoptotic members and inhibit their activity.

true

It is relatively easy to isolate and propagate embryonic stem cells.

true

Most differentiated cell types do not themselves proliferate, but they can be replaced by the proliferation of stem cells.

true

Programmed cell death plays an important role in development.

true

Reproductive cloning of humans raises ethical concerns.

true

Satellite cells are located beneath the basal lamina of muscle fibers.

true

The clinical application of adult stem cells is limited by difficulties in isolating and culturing the appropriate stem cell populations.

true

Which of the following is not considered a viable source of stem cells?

tumor cell