Cell Death and Renewal Flashcards
1
Q
- Humans possess about _______ different cell types.
a. 100
b. 200
c. 500
d. 1000
e. 2000
A
b. 200
2
Q
- In adult organisms, cell death must be balanced by cell
a. growth.
b. differentiation.
c. renewal.
d. migration.
e. All of the above
A
e. All of the above
3
Q
- The distinct series of changes that characterizes programmed cell death is called
a. necrosis.
b. sepsis.
c. apoptosis.
d. execution.
e. lysis
A
c. apoptosis.
4
Q
- During development, 50% of neurons die; those that survive are those that
a. generated axons.
b. received epithelial growth factor.
c. made correct connections with their target cells.
d. did not receive an extracellular cell death signal.
e. lacked the cell death pathway proteins.
A
d. did not receive an extracellular cell death signal
5
Q
- 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
A
e. All of the above are part of apoptosis
6
Q
- Cells that die as the result of acute injury undergo
a. lysis.
b. sepsis.
c. apoptosis.
d. execution.
e. narcolepsy
A
d. execution.
7
Q
7. 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
A
c. gain; phosphatidylserines
8
Q
- 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
A
d. caspase.
9
Q
- Ced-9 functions directly to _______ Ced- _______.
a. inhibit; 3
b. inhibit; 4
c. stimulate; 3
d. stimulate; 4
e. stimulate; 6
A
b. inhibit; 4
10
Q
- 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.
A
d. Apaf-1, caspase-9, and cytochrome c.
11
Q
- Effector caspases cleave
a. nuclear lamins.
b. cytoskeletal proteins.
c. DNase inhibitor.
d. only other caspases.
e. a, b, and c
A
e. a, b, and c
12
Q
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
A
d. cytochrome c
13
Q
- 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.
A
c. all antiapoptotic.
14
Q
- 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.
A
c. forming oligomers in the mitochondrial outer membrane that release cytochrome c.
15
Q
15. 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
A
c. p53.
16
Q
- Grim and Reaper act by _______ the activity of _______.
a. stimulating; inhibitors of apoptosis (IAPs)
b. inhibiting; inhibitors of apoptosis (IAPs)
c. inhibiting; apoptosomes
d. inhibiting; caspase-3
e. stimulating; Bad
A
b. inhibiting; inhibitors of apoptosis (IAPs)
17
Q
17. 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
A
a. PI 3-kinase/Akt
18
Q
- Which of the following is phosphorylated by Akt?
a. Bad
b. p53
c. FOXO
d. All of the above
e. None of the above
A
a. Bad
19
Q
- Most cells in adult animals are in the _______ stage of the cell cycle.
a. G1
b. G2
c. S
d. G0
e. M
A
d. G0
20
Q
- Fibroblasts are stimulated to exit G0 and proliferate by _______ growth factor.
a. fibroblast
b. platelet-derived
c. epithelial
d. stem cell
e. epidermal
A
b. platelet-derived
21
Q
- 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
A
d. All of the above
22
Q
- 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.
A
d. cells deprived of oxygen.
23
Q
- 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
A
c. all blood cells and macrophages.
24
Q
- 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
A
b. at the bottom of
25
Q
- 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
A
d. transit-amplifying
26
Q
- 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
A
c. satellite cells.
27
Q
- 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.
A
c. trophoblast cells.
28
Q
28. 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.
A
b. LIF.
29
Q
29. Of the offspring that result from the reproductive cloning of mammals by somatic nuclear transfer, \_\_\_\_\_\_\_ are viable. a. 1–3% b. 10% c. 15–20% d. 25% e. 50%
A
a. 1–3%
30
Q
- Apoptosis, or programmed cell death, occurs in all of the following cases except
a. virus-infected cells.
b. in cells damaged by injury.
c. in cells with potentially cancer-causing mutations.
d. during the elimination of tissue between the digits in the formation of human fingers.
A
b. in cells damaged by injury.
31
Q
- 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
A
d. All of the above
32
Q
- 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
A
c. They predominantly break up Golgi membranes, which in turn release other caspases
to cleave nuclear lamins and cytoskeleton proteins.
33
Q
- The Bcl-2 family of proteins is divided into three functional groups which contain and
share as many as four Bcl-2 homology domains (BH domains). Which of the following is
common to all member of the Bcl-2 family?
a. BH1
b. BH2
c. BH3
d. BH4
A
c. BH3
34
Q
- 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.
A
c. When activated, Bax and Bak form oligomers in the outer membrane of mitochondria,
leading to the release of cytochrome c.
35
Q
- Inhibitors of apoptosis (IAPs) regulate caspases. Which of the following statements
about IAPs is false?
a. IAPs were discovered in virus-infected insect cells as viral proteins that inhibited
apoptosis of the host cell in response to viral infection.
b. IAPs target caspases for ubiquitination and degradation in the proteasome.
c. IAPs are activated through the p53 pathway.
d. IAPs directly interact with caspases
A
c. IAPs are activated through the p53 pathway.
36
Q
- 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
A
b. p53
37
Q
- 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.
A
d. PI 3-kinase phosphorylates PIP2 to form PIP3.
38
Q
- 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. All of the above
A
d. All of the above
39
Q
- 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
A
b. Neurons
40
Q
- 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.
A
c. Stem cells in organs can only differentiate into the tissue in which they are located.
41
Q
- 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
A
d. All of the above
42
Q
- Which of the following cells cannot develop from hematopoietic stem cells?
a. Macrophages
b. Platelets
c. B lymphocytes
d. Satellite cells
A
d. Satellite cells
43
Q
15. 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
A
d. All of the above
44
Q
- 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
A
a. Embryonic stem cells
45
Q
- 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)
A
b. LIF (leukemia inhibitory factor)
46
Q
- 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
A
b. Somatic cell nuclear transfer was first carried out in frogs in the 1950s.
47
Q
- Which of the following diseases represents an ideal target for therapeutic cloning?
a. Diabetes
b. Parkinson’s disease
c. Spinal cord injury
d. All of the above
A
d. All of the above
48
Q
- What is the best rationale for the use of therapeutic cloning to replace defective cells
or tissues in a patient?
a. The transplanted cells are identical to those of the recipient who donated the adult
nucleus, so complications of immune rejection are avoided.
b. Embryos do not have to be destroyed, so ethically there is little controversy.
c. It is a very efficient process for generating the tissues that need to be replaced.
d. We already know how to fully differentiate the embryonic stem cells into all the major
cell types.
A
a. The transplanted cells are identical to those of the recipient who donated the adult
nucleus, so complications of immune rejection are avoided.
