Chapter 18 Study Questions

Question 1

2. In adult organisms, cell death must be balanced by cell
   a. growth.
   b. differentiation.
   c. renewal.
   d. migration.
   e. All of the above

Answer 1

c. renewal.

Question 2

necrosis.
b. sepsis.
c. apoptosis.
d. execution.
e. lysis.

Answer 2

e. lysis.

Question 3

Which of the following events is not part of apoptosis?

a. Fragmenting of chromosomal DNA
b. Fragmenting of the nucleus
c. Fragmenting of the cell
d. Lysis of cell fragments and release of their contents
e. All of the above are part of apoptosis.

Answer 3

d. Lysis of cell fragments and release of their contents

Question 4

. Cells that die as the result of acute injury undergo

a. lysis.
b. sepsis.
c. apoptosis.
d. execution.
e. narcolepsy

Answer 4

a. lysis.

Question 5

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

a. loss; carbohydrates
b. loss; phosphatidylserines
c. gain; phosphatidylserines
d. gain; phosphatidylethanolamines
e. gain; carbohydrates

Answer 5

c. gain; phosphatidylserines

Question 6

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

a. serine protease.
b. chymotrypsin.
c. ubiquitin-targeted protease.
d. caspase.
e. calcium-activated protease.

Answer 6

d. caspase.

Question 7

Ced-9 functions directly to _______ Ced- _______.

a. inhibit; 3
b. inhibit; 4
c. stimulate; 3
d. stimulate; 4
e. stimulate; 6

Answer 7

b. inhibit; 4

Question 8

An apoptosome is a complex containing multiple subunits of

a. Apaf-1.
b. Apaf-1 and caspase-9.
c. Apaf-1 and caspase-3.
d. Apaf-1, caspase-9, and cytochrome c.
e. Apaf-1, caspase-9, cytochrome c, and caspase-3

Answer 8

d. Apaf-1, caspase-9, and cytochrome c.

Question 9

. Effector caspases cleave

a. nuclear lamins.
b. cytoskeletal proteins.
c. DNase inhibitor.
d. only other caspases.
e. a, b, and c

Answer 9

e. a, b, and c

Question 10

12. Many stimuli that trigger cell death release the molecule _______ from mitochondria to bind to Apaf-1.

a. ATP synthase
b. citric acid
c. ubiquinone
d. cytochrome c
e. succinate

Answer 10

d. cytochrome c

Question 11

. Members of the Bcl-2 family of proteins are

a. all caspases.
b. all proapoptotic.
c. all antiapoptotic.
d. either antiapoptotic or proapoptotic.
e. neither antiapoptotic nor proapoptotic

Answer 11

d. either antiapoptotic or proapoptotic.

Question 12

14. Bax and Bak act by
    a. interacting with Apaf-1 to initiate a proapoptotic signal.
    b. interacting with Ced-9 to initiate a proapoptotic signal.
    c. forming oligomers in the mitochondrial outer membrane that release cytochrome c.
    d. interacting with Apaf-1 to block an apoptotic signal.
    e. interacting with caspase-9 to form an apoptosome.

Answer 12

c. forming oligomers in the mitochondrial outer membrane that release cytochrome c.

Question 13

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

a. Akt.
b. pRB.
c. p53.
d. p15.
e. mTOR.

Answer 13

c. p53.

Question 14

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

a. PI 3-kinase/Akt
b. Hedgehog
c. TNF
d. Wnt
e. BH3

Answer 14

a. PI 3-kinase/Akt

Question 15

. Which of the following is phosphorylated by Akt?

a. Bad
b. p53
c. FOXO
d. All of the above
e. None of the above

Answer 15

d. All of the above

Question 16

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

a. G1
b. G2
c. S
d. G0
e. M

Answer 16

d. G0

Question 17

Fibroblasts are stimulated to exit G0 and proliferate by _______ growth factor.

a. fibroblast
b. platelet-derived
c. epithelial
d. stem cell
e. epidermal

Answer 17

b. platelet-derived

Question 18

Which of the following adult cell types is arrested in G0? 
a.	Fibroblasts 
b.	Endothelial cells 
c.	Liver cells 
d.	All of the above 
e.	None of the above 
Textbook Reference

Answer 18

d. All of the above

Note liver is the only only one that stays unless surgery

Question 19

. VEGF is secreted by

a. platelets.
b. injured endothelial cells.
c. injured smooth muscle cells.
d. cells deprived of oxygen.
e. cells deprived of VEGF

Answer 19

d. cells deprived of oxygen.

Question 20

. Hematopoietic stem cells can give rise to

a. erythrocytes.
b. erythrocytes and lymphocytes.
c. all blood cells and macrophages.
d. all blood cells, macrophages, and skin cells.
e. all blood cells, macrophages, skin cells, and lung cells

Answer 20

c. all blood cells and macrophages

Question 21

. Intestinal epithelial stem cells are located _______ the crypt.

a. at the top of
b. at the bottom of
c. at the sides of
d. throughout
e. next to but are not part of

Answer 21

b. at the bottom of

Question 22

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

a. goblet
b. crypt
c. G0
d. transit-amplifying
e. enteroendocrine

Answer 22

d. transit-amplifying

Question 23

The stem cells of skeletal muscle are called

a. myoblasts.
b. myocytes.
c. satellite cells.
d. myo-stem cells.
e. No stem cells are found in skeletal muscle

Answer 23

c. satellite cells.

Question 24

27. Mammalian embryonic stem cells are cultured from cells taken from
    a. the 4-cell embryo.
    b. the inner cell mass.
    c. trophoblast cells.
    d. amnion cells.
    e. chorion cells.

Answer 24

b. the inner cell mass.

Question 25

Mouse embryonic stem cells can proliferate but remain undifferentiated in the presence of a growth factor called a. Dif. b. LIF. c. EGF. d. Wnt. e. Scf.

Answer 25

b. LIF.

Question 26

. Which of the following events occurs during apoptosis? a. Chromosomal DNA is fragmented. b. Chromatin condenses. c. The cell nucleus breaks up. d. All of the above

Answer 26

d. All of the above

Question 27

Which of the following statements about caspases is false? a. They cleave target proteins after aspartic acid residues. b. They inhibit DNAse which, when activated, fragments nuclear DNA. c. They predominantly break up Golgi membranes, which in turn release other caspases to cleave nuclear lamins and cytoskeleton proteins. d. They contain cysteine residues in the active site.

Answer 27

c. They predominantly break up Golgi membranes, which in turn release other caspases to cleave nuclear lamins and cytoskeleton proteins.

Question 28

Which of the following statements is true in reference to Bax and Bak, two members of the Bcl-2 family? a. Bax and Bak are antiapoptotic proteins that function to repress apoptosis in cells. b. Bax and Bak act as ligands to the apoptosome in activation caspases. c. When activated, Bax and Bak form oligomers in the outer membrane of mitochondria, leading to the release of cytochrome c. d. Bax and Bak directly activate caspase-9.

Answer 28

When activated, Bax and Bak form oligomers in the outer membrane of mitochondria, leading to the release of cytochrome c.

Question 29

The following is a cascade of signal transduction initiating with double-stranded DNA damage and ending with activation of apoptosis by the BH3-only proteins PUMA and Noxa. What protein is missing in the blank? Double-strand DNA damage; Chk2; _______; PUMA/Noxa; Apoptosis a. Apaf-1 b. p53 c. Chk1 d. Bax

Answer 29

b. p53

Question 30

The PI 3-kinase pathway is important in countering apoptosis in healthy cells and promotes cell survival. Which of the following statements about the PI 3-kinase pathway is false? a. PI 3-kinase is activated by a receptor tyrosine kinase. b. PIP3 activates Akt, a serine/threonine kinase. c. Activated Akt phosphorylates and activates Bad. d. PI 3-kinase phosphorylates PIP2 to form PIP3

Answer 30

c. Activated Akt phosphorylates and activates Bad.

Question 31

. TNF and related cytokines can directly induce apoptosis. Which of the following statements about TNF-mediated induction of apoptosis is true? a. TNF binds a trimeric receptor complex on the surface of the cell membrane. b. Upon receptor binding, caspase-8 is activated through an adaptor protein. c. Caspase-8 activates Bid, which in turn activates Bax and Bak and then feeds into the mitochondrial pathway. d. d. All of the above

Answer 31

d. d. All of the above

Question 32

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? a. Fibroblasts b. Neurons c. Endothelial cells d. Epithelial cells

Answer 32

b. Neurons

Question 33

In reference to stem cells, which of the following statements is false? a. Stem cells divide to form one daughter cell that remains a stem cell and a second cell that proliferates and then differentiates. b. Stem cells are a subpopulation of less differentiated self-renewing cells present in most adult tissues. c. Stem cells in organs can only differentiate into the tissue in which they are located. d. Stem cells in tissues are typically found in G0, unless called on to differentiate.

Answer 33

c. Stem cells in organs can only differentiate into the tissue in which they are located.

Question 34

Which of the following represents a viable source of stem cells? a. Umbilical cord blood only b. Bone marrow only c. An embryo only d. All of the above

Answer 34

d. All of the above

Question 35

Which of the following cells cannot develop from hematopoietic stem cells? a. Macrophages b. Platelets c. B lymphocytes d. Satellite cells

Answer 35

d. Satellite cells

Question 36

Bone marrow transplants are used to treat patients with which of the following diseases? a. Aplastic anemia b. Hemoglobin disorders c. Immune deficiencies d. All of the above

Answer 36

d. All of the above

Question 37

Which of the following stem cells have the capacity to give rise to all the differentiated cell types of adult organisms? a. Embryonic stem cells b. Endothelial cells c. Satellite cells d. Epithelial cells

Answer 37

a. Embryonic stem cells

Question 38

. Murine embryonic stem cells are grown in the presence of a growth factor. What growth factor is generally used for this? a. VEGF (vascular endothelial growth factor) b. LIF (leukemia inhibitory factor) c. PDGF (platelet-derived growth factor) d. EGF (epidermal growth factor)

Answer 38

b. LIF (leukemia inhibitory factor)

Question 39

. Which of the following statements about cloning by somatic cell nuclear transfer is false? a. The nucleus of an adult somatic cell is transferred to an enucleated unfertilized egg. b. Somatic cell nuclear transfer was first carried out in frogs in the 1950s. c. In the laboratory, the cloned egg is cultured to an early embryo stage and then transferred to a foster mother. d. The cloned embryo is genetically identical to the foster mother

Answer 39

d. The cloned embryo is genetically identical to the foster mother.