Cell Cycle (Cell Death)

Question 1

The development and maintenance of multicellular organisms depend not only on cell growth and cell division but also on ____ _____

Answer 1

Cell Death

Question 2

cells die at the same rate as they are produced

Answer 2

maintenance of tissue size

Question 3

programmed cell death; “falling off”

Answer 3

Apoptosis

Question 4

rapidly engulfs the cell and fragments before they can spill their contents.

Answer 4

Macrophages

Question 5

-cells that die in response to an acute insult.
-swell and burst, spilling their contents eliciting inflammatory response

Answer 5

cell necrosis

Question 6

a form of programmed cell death that is triggered by a specific regulatory signal from other cells

Answer 6

necroptosis

Question 7

cell death help sculpt hands and feet during _________ ___________.

Answer 7

embryonic development

Question 8

also functions as a quality-control process in development, eliminating cells that are abnormal, misplaced, nonfunctional, or potentially dangerous to the animal.

Answer 8

Apoptosis

Question 9

must be tightly regulated to ensure that they are exactly in balance

Answer 9

cell death and cell division

Question 10

cell can kill themselves by undergoing apoptosis

Answer 10

damages (DNA damages)

Question 11

triggered by members of a family of
specialized intracellular proteases

Answer 11

Apoptosis

Question 12

have a cysteine at their active site and cleave their target proteins at specific aspartic acids

Answer 12

caspases

Question 13

begin the apoptotic process; apoptotic signal -> assembly of large protein complexes -> dimers -> protease activation

Answer 13

initiator caspases

Question 14

initiator caspases activate ___________ ________

Answer 14

executioner caspases

Question 15

inactive dimers; cleaved by an initiator caspase at a site in the protease domain -> rearranged to active form ->amplifying proteolytic cascade-> kill the cell

Answer 15

executioner caspases

Question 16

-cleavage -> irreversible breakdown of nuclear lamina
-a protein that normally holds a DNA-degrading endonuclease (iCAD) in an inactive form; its cleavage frees the endonuclease (CAD) to cut up the DNA in the cell nucleus

Answer 16

lamins

Question 17

self-amplifying and irreversible

Answer 17

caspase cascade

Question 18

How is the initiator caspase first activated in response to an apoptotic signal?

Answer 18

-extrinsic pathway and intrinsic and intrinsic
-mitochondrial pathway

Question 19

Is signaled from outside the cell

Answer 19

intrinsic pathway

Question 20

Is signaled from mitochondria inside the cell

Answer 20

mitochondrial pathway

Question 21

transmembrane proteins; extracellular ligand-binding domain, a single transmembrane domain, and an intracellular death domain

Answer 21

death receptors

Question 22

The receptors are homotrimers and belong to the _____ ________ ______ ________ family.

Answer 22

tumor necrosis factor (TNF) receptor

Question 23

TNF has eight members, which includes?

Answer 23

-a receptor for TNF itself
-Fas death receptor

Question 24

ligands are also ___________

Answer 24

homotrimers

Question 25

activation of Fas

Answer 25

binding of Fas ligand -> death domains on the cytosolic tails bind intracellular adaptor proteins -> bind initiator caspases -> death-inducing signaling complex (DISC) -> activate executioner caspapses

Question 26

help prevent the inappropriate activation of the extrinsic pathway of apoptosis.

Answer 26

inhibitory proteins-FLIP

Question 27

depends on the release into the cytosol of mitochondrial proteins

Answer 27

intrinsic or mitochondrial pathway

Question 28

released proteins activate a caspase proteolytic cascade in the cytoplasm, leading to _________

Answer 28

apoptosis

Question 29

released into the cytosol -> binds to an adaptor protein called _____ (apoptotic protease activating factor-1) -> oligomerize into a wheel-like heptamer called ______ -> recruit initiator _____-_ proteins

Answer 29

cytochrome c - Apaf1 - apoptosome - caspase-9

Question 32

major class of intracellular regulators of the intrinsic pathway

Answer 32

Bcl2 family

Question 32

suppress apoptosis; controlling the release of cytochrome c and other intermembrane mitochondrial proteins into the cytosol

Answer 32

Bcl2 family

Question 33

classes of mammalian Bcl2 family proteins

Answer 33

1. Anti-apoptotic Bcl2 family proteins 2. Pro-apoptotic Bcl2 family effectors

Question 34

anti-apoptotic

Answer 34

bcl2 and BclXL

Question 35

Pro-apoptotic

Answer 35

effector Bcl2 family proteins and Bh3-only proteins

Question 36

activation of intrinsic pathway

Answer 36

apoptotic stimulus

Question 37

Bcl2 family aggregate to form oligomers in the mitochondrial outer membrane

Answer 37

activation of intrinsic pathway

Question 38

apoptotic stimulus → activated _____ pathway → ____ family aggregate to form oligomers in the mitochondrial outer membrane → release of ____ _

Answer 38

intrinsic Bcl2 cytochrome c

Question 39

main effector of intrinsic pathway

Answer 39

Bax (cytosol) and Bak (mitochondrial outer membrane)

Question 40

cytosolic surface of the outer mitochondrial membrane; help prevent inappropriate release of intermembrane proteins

Answer 40

Anti-apoptotic: Bcl and BclXL

Question 41

-to promote apoptosis mainly by inhibiting anti-apoptotic Bcl2 family proteins -enables the aggregation of Bax and Bak on the surface of mitochondria, which triggers the release of the intermembrane mitochondrial proteins that induce apoptosis.

Answer 41

BH3-only proteins

Question 42

DNA damage -> tumor suppressor protein __ accumulates and activates the transcription of genes that encode the BH3-only proteins ____ and _____ ->trigger the ___ pathway

Answer 42

p53 Puma and Noxa intrinsic

Question 43

cell employs multiple ______ __________ to ensure that these proteases are activated only when appropriate

Answer 43

robust mechanisms

Question 44

-Another lone of defense against inappropriate caspase activation is provided by caspase inhibitor proteins called -first identified in certain insect viruses (baculoviruses), which encode IAP proteins to prevent a host cell that is infected by the virus from killing itself by apoptosis.

Answer 44

inhibitors of apoptosis (IAPs)

Question 45

destruction for proteosomes

Answer 45

polyuquitylate caspases

Question 46

IAP-binding domain which binds to the BIR domain of IAPs, preventing the domain from binding to a caspase

Answer 46

anti-IAPS (Drosophila)-Reaper, Grim, and Hid

Question 47

are released from the mitochondrial intermembrane space when the intrinsic pathway of apoptosis is activated, blocking IAPs in the cytosol and thereby promoting apoptosis.

Answer 47

Anti-IAPs

Question 48

inhibit apoptosis

Answer 48

extracellular survival factors

Question 49

nerve cells are produced in excess in the __________ _______ ______

Answer 49

developing nervous system

Question 50

receive enough signal survival signals live, while others die.

Answer 50

compete for limited amounts of survival factors

Question 51

the number of surviving _______ is automatically adjusted so that it is appropriate for the number of target cells they connect with

Answer 51

neurons

Question 52

bind to cell-surface receptors, which activate intracellular signaling pathways that suppress the apoptotic program, usually by regulating the expression or activity of members of the Bcl2 family of proteins.

Answer 52

survival factors

Question 53

thereby enabling IAP proteins to suppress apoptosis

Answer 53

phosphorylating and inactivating anti-IAP proteins such as Hid

Question 54

the apoptotic cell and its fragments do not break open and release their contents, but instead remain intact as they are efficiently eaten or ____________ by neighboring cells.

Answer 54

phagocytysed

Question 55

chemical changes on the surface of the apoptotic cell recruit __________ _____

Answer 55

phagocytic cells

Question 56

located exclusively in the inner leaflet of the lipid bilayer, but it flips to the outer leaflet in apoptotic cells

Answer 56

phosphatidylserine

Question 57

healthy cells express signal proteins on their surface that interact with inhibitory receptors on macrophages that block phagocytosis

Answer 57

macrophages do not phagocytose healthy cells

Question 58

cells die by necrosis as a result of ischemia

Answer 58

heart attacks or strokes

Question 59

inactivate the genes that encode the Fas death receptor or the Fas ligand

Answer 59

conditions where too few cells die by apoptosis

Question 60

accumulate in spleen and lymph -> autoimmune disease

Answer 60

prevent normal death of some lymphocytes

Question 61

tumors, cancer cells regulate their apoptotic program abnormally

Answer 61

decreased apoptosis

Question 62

-chromosome translocation causes excessive production of the Bcl2 protein; B cell lymphoma -development of cancer by inhibiting apoptosis; decrease the cells' sensitivity to anticancer drugs

Answer 62

Bcl2 gene

Question 63

-gene encoding the _____ __________ ______ ___ is mutated in about 50% of human cancers -can no longer promotes apoptosis or cell-cycle arrest in response to DNA damage -enables the cancer cells to survive and proliferate even when their DNA is damaged

Answer 63

tumor suppressor protein p53

Question 64

small chemical that interfere with the function of anti-apoptotic Bcl2 family proteins

Answer 64

drugs that stimulate apoptosis

Question 65

spade-like structures →individual digits separate only as the cells between them die

Question 66

cells die when the structure they form is no longer needed →

Answer 66

tadpole to frog; tail is not needed in the frog

Question 67

two major classes of apoptotic caspases

Answer 67

initiator caspases and executioner caspases.

Question 68

initiator caspases - begin the apoptotic process;apoptotic signal →

Answer 68

triggers the assembly of large protein

Question 69

begin the apoptotic process; apoptotic signal → assembly of large protein complexes →

Answer 69

caspases associate to form dimers

Question 70

begin the apoptotic process; apoptotic signal → assembly of large protein complexes → dimers →

Answer 70

protease activation

Question 71

executioner caspases - inactive dimers; cleaved by an initiator caspase at a site in the protease domain →

Answer 71

rearranged to active form

Question 72

Inactive dimers; cleaved by an initiator caspase at a site in the protease domain → rearranged to active form →

Answer 72

amplifying proteolytic cascade

Question 73

inactive dimers; cleaved by an initiator caspase at a site in the protease domain → rearranged to active form → amplifying proteolytic cascade →

Answer 73

kill the cell

Question 74

a protein that normally holds a ___-______ ______ in an inactive form; its cleavage frees the ________ to cut up the DNA in the cell nucleus

Answer 74

DNA- degrading endonuclease (iCAD) endonuclease (CAD)

Question 75

proteins that are cleaved by caspases during apoptosis

Answer 75

- nuclear lamins - a protein that normally holds a DNA- degrading endonuclease (iCAD) in an inactive form - components of the cytoskeleton and cell– cell adhesion proteins

Question 76

inhibit apoptosis mainly by binding to and inhibiting pro-apoptotic Bcl2 family proteins

Answer 76

anti-apoptotic