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Cell and Molecular Biology > Module 7: The Cell Cycle Part 2 (Cytokinesis, Meiosis, Control of Cell Division and Cell Growth, Cell Death) > Flashcards

Module 7: The Cell Cycle Part 2 (Cytokinesis, Meiosis, Control of Cell Division and Cell Growth, Cell Death) Flashcards

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1
Q

The final stage of the cell cycle, where the cytoplasm divides into two daughter cells.

A

Cytokinesis

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2
Q

When cells undergo mitosis without cytokinesis, they become __, containing multiple nuclei in a single cytoplasm.

A

multinucleated

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3
Q

What marks the beginning of cytokinesis on the cell surface?

A

appearance of a pucker or cleavage furrow

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4
Q

What structure is responsible for the physical separation of the cytoplasm?

A

contractile ring

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5
Q

The separation of sister chromatids during anaphase triggers the assembly of…

cytokinesis

A

contractile ring

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6
Q

Which proteins accumulate in the contractile ring during cytokinesis as the sister chromatids separate in anaphase? (2)

A
  • Actin
  • myosin II
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7
Q

What protein is responsible for the local formation of actin filaments in the contractile ring which facilitates the assembly of parallel arrays of linear, unbranched actin filaments?

cytokinesis

A

Formin

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8
Q

Overlapping arrays of __ and __ contract to generate the force that divides the cytoplasm in two.

cytokinesis

A

-actin; and
- myosin II filaments

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9
Q
  • a structure that persists as a tether between the two daughter cells and contains the remains of the __.
  • a large protein structure derived from antiparallel interpolar microtubules of the spindle midzone, tightly packed together within a dense matrix material.

cytokinesis (main answer, blank-2)

A

Midbody
- central spindle

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10
Q
  • a small GTPase of the Ras superfamily that plays a critical role in cell division.
  • controls the assembly and function of the contractile ring at the site of cleavage.
  • promotes actin filament formation, myosin II assembly, and ring contraction at the cell cortex.
  • activates formins and multiple protein kinases, including Rho-associated protein kinase (Rock).
A

RhoA

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11
Q
  • Cytokinesis must occur only after the two sets of chromosomes are __ from each other.
  • The __ must be placed between the two sets of daughter chromosomes.
  • The correct timing and position depend on the __.
A
  • fully segregated
  • site of division
  • mitotic spindle
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12
Q
  • During anaphase, the spindle generates signals that initiate __ at a position midway between the spindle poles.
  • The correct timing involves the __ of __, which depends on cyclin destruction in metaphase and anaphase.
A
  • furrow formation
  • dephosphorylation
  • Cdk substrates
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13
Q
  • the first model that explains how the mitotic spindle specifies the site of division
  • Astral microtubules carry furrow-inducing signals.
A

Astral Stimulation Model

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14
Q
  • the second model that describes the mitotic spindle’s role in specifying the site of division
  • The spindle midzone, or central spindle, generates a furrow-inducing signal that specifies the site of furrow formation at the cell cortex.
A

Central Spindle Stimulation Model

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15
Q
  • third model that outlines the mitotic spindle’s mechanism in specifying the division site
  • The astral microtubules promote local relaxation of actin-myosin bundles at the cell cortex, with minimal relaxation at the spindle equator, thus promoting cortical contraction.
A

Astral Relaxation Model

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16
Q
  • Higher-plant cells are enclosed by a semirigid (1)__.
  • The cytoplasm is partitioned by the construction of a new cell wall called the (2)__, which forms between the two daughter nuclei.
  • The formation of the (2)__ begins in (3)__ and is guided by the (4)__, which contains microtubules derived from the mitotic spindle.

cytokinesis in plants

A

1) cell wall
2) cell plate
3) late anaphase
4) phragmoplast

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17
Q
  • Each daughter cell must inherit __ essential cell components, including membrane-enclosed organelles.
  • Organelles can arise only by the growth and division of __.
  • __ and __ are usually present in large enough numbers to double during each cell cycle.

cytokinesis in plants

A
  • all
  • preexisting organelles
  • Mitochondria
  • chloroplasts
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18
Q

What organelles?
- The __ is cut into two during cytokinesis.
- The __ is reorganized and fragmented during mitosis.

cytokinesis in plants

A
  • Endoplasmic reticulum (ER)
  • Golgi apparatus
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19
Q

A cell division is when cells divide to produce two daughter cells that differ in size, cytoplasmic contents, or both.

A

Asymmetric cell division

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20
Q

The mother cell must first segregate __ to one side and then position the plane of division so that the appropriate daughter cell inherits these components.

A

cell fate determinants

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21
Q

When cells undergo multiple rounds of nuclear division without intervening cytoplasmic division, it leads to the formation of a __, where many nuclei share a common cytoplasm.

A

syncytium

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22
Q

In which organism does the first 13 rounds of nuclear division occur without cytoplasmic division?

A

Drosophila (fruit fly) embryo

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23
Q

What is the advantage of multiple nuclear divisions without cytoplasmic division in early development?

A

greatly speeds up early development

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24
Q

During __, membranes are created around each nucleus in one round of coordinated cytokinesis.

A

cellularization

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25
Q

Name three types of cells that may undergo polyploidy or large cell formation. (3)

A
  • megakaryocytes
  • hepatocytes
  • heart muscle cells
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26
Q

Generates genetically distinct offspring by mixing the genomes of two parents and reducing the chromosome number by half.

A

Meiosis

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27
Q

contain two homologs of each chromosome, one from each parent.

A

diploid cells

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28
Q

carry only a single copy of each chromosome, typical of gametes (sperm and egg).

A

haploid cells

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29
Q

When sperm and egg fuse, they form a __, a diploid cell with a complete set of chromosomes.

A

zygote

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30
Q

Meiosis produces __ (how many?) __ (what kind of cell?) daughter cells, each carrying a maternal or paternal chromosome copy.

A
  • four
  • haploid
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31
Q

Duplication of chromosomes occurs in preparation for division.

What phase?

A

S Phase

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32
Q

Meiosis involves __ successive rounds of __.

A
  • two
  • chromosome segregation
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33
Q

During meiosis I, what pair up and are segregated into two cells?

A

Homologous chromosomes (paternal and maternal)

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34
Q

No further DNA replication occurs, and sister chromatids are pulled apart and segregated.

A

Meisois II

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35
Q

Homologs __ and __ physically during meiosis, to ensure the maternal and paternal homologs are bi-oriented on the first meiotic spindle.

A
  • recognize
  • associate
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36
Q

A prolonged phase where homologous chromosomes begin pairing through interactions at specific pairing sites.

A

meiotic prophase I

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37
Q

A four-chromatid structure formed during meiosis I when homologous chromosomes pair up.

A

bivalent

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38
Q

Homolog pairs are locked together during meiosis through __, which stabilizes the bivalent structure.

A

homologous recombination

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39
Q
  • The exchange of DNA between chromatids, where a segment of a chromatid becomes continuous with a segment of its homolog.
  • They ensure accurate segregation of homologs and contribute to genetic diversity in offspring.
A

crossover

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40
Q

During meiosis, paired homologs are brought into close __ , aligning their structural axes (__).

A
  • juxtaposition
  • axial cores

juxtapstn-placing two opposing elements close together or side by side

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41
Q

A protein assembly that binds to a double-strand break in a chromatid, matches it to the DNA sequence in the nearby homolog, and helps reel in the partner chromosome.

A

recombination complex

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42
Q

The initial stage in homolog pairing, which leads to synapsis—the tight linking of homolog axial cores.

A

presynaptic alignment

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43
Q

__ form part of the __ mediates the tight linkage of homologous axial cores during synapsis

A
  • Transverse filaments
  • synaptonemal complex
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44
Q

A protein structure that stabilizes paired homologs during meiosis by tightly linking their axial cores.

A

synaptonemal complex

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45
Q

What are the five sequential stages of meiotic prophase? (5)

A

1) Leptotene
2) Zygotene
3) Pachytene
4) Diplotene
5) Diakinesis

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46
Q

Homologs condense and pair, and genetic recombination begins.

Prophase I

A

Leptotene

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47
Q

The synaptonemal complex begins to assemble at sites where homologs are closely associated, and recombination events occur.

Prophase I

A

Zygotene

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48
Q

The assembly of the synaptonemal complex is complete, and homologs are fully synapsed along their entire lengths.

Prophase I

A

Pachytene

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49
Q

The disassembly of synaptonemal complexes, accompanied by the condensation and shortening of chromosomes.

Prophase I

A

Diplotene

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50
Q

Segregation of homologs begins as chromosomes prepare for metaphase I.

Prophase I

A

Diakinesis

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51
Q
  • the visible connections between nonsister chromatids of homologous chromosomes, resulting from individual crossover events during meiosis.
  • stabilize homologous pairs (bivalents) and help ensure accurate segregation of homologs during meiosis I.
A

Chiasmata

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52
Q

Three features of meiosis I that distinguish it from mitosis:
1. Both __ in a homolog attach to the __ spindle pole in meiosis I.
2. __ generate a strong physical linkage between homologs, enabling their bi-orientation at the spindle equator.
3. Cohesion is removed during __ only from the __, not from the regions near the __ where kinetochores are located.

A
  1. sister kinetochores; same
  2. Crossovers
  3. anaphase I; chromosome arms; centromeres
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53
Q

A kinetochore-associated protein called __ protects centromeric cohesins by recruiting a phosphatase to remove phosphates, preventing separase activity.

A

shugoshin

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54
Q

Two primary functions of crossing-over during meiosis:
1. ___ for proper segregation during meiosis I.
2. Contributes to __ in gametes.

A
  • Holds homologs together
  • genetic diversity
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55
Q

Each pair of homologs is linked by about __ crossovers, with at least __ crossover forming between members of each homolog pair.

Crossing-over regulation in human homologs

A
  • 2-3
  • 1
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56
Q

DNA regions accessible to crossovers.

A

crossover “hot spots”

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57
Q

Regions like heterochromatin near centromeres and telomeres where crossovers are rare.

A

crossover “cold spots”

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58
Q

The presence of one crossover event inhibits another from forming nearby.

A

crossover interference

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59
Q
  • Errors in chromosome segregation during meiosis significant because errors, such as (1)__, can lead to gametes lacking or having extra chromosomes, causing disorders like (2)__(__).
  • (1)__ is also a major cause of (3)__ and (4)__ in humans.
A

1) nondisjunction
2) Down syndrome (trisomy 21)
3) spontaneous abortion (miscarriage)
4) mental retardation

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60
Q

Unique about meiotic arrest in human females:
- Meiosis I arrests in the diplotene stage for years, resuming only at __.
- Meiosis II is completed only after __.

A
  • ovulation
  • fertilization
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61
Q
  • What fundamental processes determines organ and body size? (3)
  • How are these processes regulated?
A
  • Cell growth
  • cell division
  • cell survival
  • By intracellular and extracellular signals.
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62
Q

Secreted proteins, proteins bound to the surface of cells, or components of the extracellular matrix.

A

extracellular signal molecules

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63
Q

Signal molecules that stimulate cell division and G1/S-Cdk activity.

A

Mitogens

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64
Q

Signal molecules that promote cell survival by suppressing apoptosis.

A

survival factors

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65
Q

A factor that has activities such as stimulating cell growth, division, or survival.

A

Growth factor

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66
Q

What is the relationship between cell growth and cell proliferation?

A

Cell growth = cell proliferation

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67
Q

What process do extracellular signal molecules activate apart from growth and survival?

A

Apoptosis

68
Q

The rate of proliferation in unicellular organisms depend on the __.

A

availability of nutrients

69
Q

Organisms that divides only when the organism needs more cells.

A

multicellular organisms

70
Q

What type of signals do cells receive to stimulate division that are stimulatory extracellular signals?

A

mitogens

71
Q

The first mitogen identified, which stimulates fibroblasts in culture to proliferate when provided with serum not when provided with plasma

A

platelet-derived growth factor (PDGF)

72
Q

What types of cells does PDGF stimulate to divide? (3)

A
  • Fibroblasts
  • smooth muscle cells
  • neuroglial cells
73
Q

A growth factor that acts on epidermal cells and many other cell types, including epithelial and nonepithelial cells.

A

epidermal growth factor (EGF)

74
Q

Only induces the proliferation of red blood cell precursors.

A

erythropoietin

75
Q

Inhibitory extracellular signal proteins that inhibit proliferation.

A

transforming growth factor-β (TGFβ)

76
Q

In the absence of a __, Cdk inhibition is maintained (G1), leading to a __ (specialized nondividing state).

A
  • mitogenic signal
  • G0 state
77
Q

The cell-cycle control system is completely dismantled, and gene expression for Cdks and cyclins is permanently turned off, and cell division rarely occurs.

A

terminally differentiated G0 state

78
Q

What can some cells do when damaged, such as liver cells?

A

Withdraw from and re-enter the cell cycle.

79
Q

Mitogens control the rate of cell division by acting in the __ phase of the cell cycle.

A

G1

80
Q

Signaling pathway initiated by a mitogen?
Mitogen
→ monomer __
→ activation of __ cascade
→ promote cell-cycle entry to __
→ increase expression of genes encoding __(__)

A
  • GTPase Ras
  • MAP kinase
  • nucleus
  • G1 cyclin (G1-Cdk)
81
Q

The activation of the MAP kinase cascade lead to the production of __, such as __, which promote cell-cycle entry.

A
  • transcription regulatory proteins
  • Myc
82
Q

It increases the expression of genes encoding G1 cyclins (G1-Cdk).

A

Myc

83
Q

They bind to specific DNA sequences in the promoters of genes required for S-phase entry.

A

E2F proteins

84
Q

An interaction between __ and members of the __ family inhibits E2F-dependent gene expression in the absence of mitogenic stimulation.

A
  • E2F
  • retinoblastoma protein (Rb)
85
Q

What results to spontaneous chemical reactions in DNA, errors in DNA replication, exposure to radiation, or certain chemicals?

A

DNA damage

86
Q

The cell-cycle control responds to DNA damage and arrests the cycle at the __ and __.

A
  • Start
  • G2/M transitions
87
Q

The signaling pathway activated by DNA damage are __ and __, which phosphorylate __ and __, leading to the stabilization of __.

A
  • ATM
  • ATR
  • Chk1
  • Chk2
  • protein p53
88
Q

stimulates transcription of the gene encoding p21 (a CKI protein), which binds G1/S-Cdk and S-Cdk complexes to inhibit their activities and block entry into the cell cycle.

A

p53

89
Q

In undamaged cells, p53 is highly unstable and present at very low concentrations due to __, which acts as a ubiquitin ligase targeting p53 for destruction.

A

Mdm2

90
Q

__ and __ phosphorylate the Cdc25 family of protein phosphatases.

A
  • Chk1
  • Chk2
91
Q

When a replication fork fails during DNA replication, low levels of DNA damage occur, and accumulation of genetic damage in cells lacking the DNA damage response increases the frequency of __.

A

cancer-promoting mutations

92
Q

Mutations in the __ are found in half of all human cancers, allowing cancer cells to accumulate mutations more readily.

A

p53 gene

93
Q

a defect in ATM, making individuals very sensitive to X-rays and leading to increased rates of cancer.

DNA damage

A

Ataxia telangiectasia

94
Q

It is the phenomenon where many human cells divide a limited number of times before undergoing a permanent cell-cycle arrest.

A

replicative cell senescence

95
Q

undergo changes that result in progressive shortening with each cell division when telomerase is not produced.

A

Telomeres

96
Q

synthesizes telomeres and promotes the formation of protein cap structures that protect chromosome ends.

A

Telomerase

97
Q

When cells do not produce telomerase, their telomeres become __ with every cell division, and their protective protein caps progressively __.

A
  • shorter
  • deteriorate
98
Q

Exposed chromosome ends are sensed as __, activating a __ arrest.

A
  • DNA damage
  • p53-dependent cell-cycle
99
Q

Most cancer cells have regained the ability to produce __, allowing them to maintain telomere function as they proliferate.

A

telomerase

100
Q

Genes that, when mutated or overexpressed, contribute to the development and progression of cancer.

A

cancer-promoting genes

101
Q

A mutation in __ can lead to a permanently overactive form, resulting in constant stimulation of Ras-dependent signaling pathways.

A

GTPase Ras

102
Q

The overexpression of __ stimulates excessive cell growth and proliferation.

A

Myc

103
Q

a cyclin-dependent kinase inhibitor protein that, when produced excessively, inhibits Mdm2, leading to increased p53 levels.

A

Arf

104
Q

Increased p53 levels can lead to __ or __.

A

cell-cycle arrest or apoptosis

105
Q

__, which involves the accumulation of proteins and other macromolecules, accompanies cell division.

A

Cell growth

106
Q

Cell growth is the accumulation of proteins and other macromolecules by increasing the rate of __ and decreasing the rate of __ of proteins and macromolecules.

A
  • synthesis
  • degradation
107
Q

Activates the kinase TOR, which stimulates metabolic processes in the cell.

A

phosphoinositide 3-kinase (PI 3-kinase)

108
Q

What are two targets activated by TOR to stimulate protein synthesis?

A
  • S6 kinase (S6K)
  • eIF4E (translation initiation factor).
109
Q
  • In yeasts, the rate of cell division is governed by the rate of cell growth, with division occurring only when growth achieves a __.
  • In yeast, what primarily regulates the rate of cell growth and division?
A
  • minimal threshold
  • Levels of extracellular nutrients
110
Q

Programmed cell death, characterized by specific morphological changes and the formation of apoptotic bodies.

A

Apoptosis

111
Q

Apoptotic bodies are removed and engulfed by __.

A

macrophages

112
Q

Cell death in response to an acute insult, where cells swell, burst, and spill their contents, causing an inflammatory response.

A

Cell necrosis

113
Q

A form of programmed cell death triggered by a specific regulatory signal from other cells.

A

Necroptosis

114
Q

maintained by cells dying at the same rate as they are produced.

apoptosis

A

Tissue size

115
Q

Sculpts hands and feet by causing the cells between spade-like structures to die, separating individual digits.

A

Cell death

116
Q

During the transformation of a tadpole into a frog, the cells of the __ die through __ as the structure is no longer needed in the frog.

A
  • tail
  • apoptosis
117
Q

In cell death, the __ process in development eliminates cells that are abnormal, misplaced, nonfunctional, or potentially dangerous to the animal.

A

quality-control

118
Q

__ and __ must be tightly regulated to ensure that they are exactly in balance, maintaining proper tissue size and function.

A
  • Cell death
  • cell division
119
Q

In this, cells may kill themselves by undergoing apoptosis to prevent further harm.

A

damages (DNA damage)

120
Q

Apoptosis is triggered by specialized __ known as caspases.

A

intracellular proteases

121
Q

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

apoptosis

A

Caspases

122
Q

begin the apoptotic process by forming dimers upon an apoptotic signal, leading to protease activation.

apoptosis

A

Initiator caspases

123
Q
  • are cleaved by initiator caspases to become active, leading to a proteolytic cascade that kills the cell.
  • They amplify apoptosis through a proteolytic cascade that degrades cellular components, ensuring cell death.

apoptosis

A

Executioner caspases

124
Q

Its cleavage leads to the irreversible breakdown of the nuclear lamina

Apoptosis

A

Lamin

125
Q

Cleavage of __ frees the DNA-degrading endonuclease CAD, which cuts up the DNA in the cell nucleus.

apoptosis

A

iCAD

126
Q

self-amplifying and irreversible

apoptosis

A

caspase cascade

127
Q

What are the two pathways that trigger apoptosis? (2)

A
  • extrinsic pathway
  • intrinsic mitochondrial pathway
128
Q
  • are transmembrane proteins with an extracellular ligand-binding domain, a single transmembrane domain, and an intracellular death domain.
  • belong to the TNF receptor family.

apoptosis

A

Death receptors

129
Q

The ligands for death receptors are __, such as __ and __ ligand.

apoptosis

A
  • homotrimers
  • TNF
  • Fas
130
Q

Activation of Fas:
Binding of Fas ligand
→ __ domains on cytosolic tails bind __ proteins
→ __ proteins bind __
→ form the __(__)
→ activate __.

apoptosis

A
  • death
  • intracellular adaptor
  • adaptor
  • initiator caspases
  • death-inducing signaling complex (DISC)
  • executioner caspases
131
Q

an inhibitory protein that helps prevent inappropriate activation of the extrinsic apoptosis pathway.

A

FLIP

132
Q

It is triggered by stresses or developmental signals inside the cell, leading to the release of mitochondrial proteins into the cytosol.

apoptosis

A

intrinsic or mitochondrial pathway

133
Q

After mitochondrial proteins are released into the cytosol, they activate a __ in the cytoplasm, leading to apoptosis.

A

caspase proteolytic cascade

134
Q

released into the cytosol and binds to Apaf1 (apoptotic protease activating factor-1), leading to the formation of an apoptosome.

A

Cytochrome c

135
Q

Cytochrome c is released into the cytosol and binds to __(__), leading to the formation of an apoptosome.

A

Apaf1 (apoptotic protease activating factor-1)

136
Q
  • a wheel-like heptamer formed by the oligomerization of Apaf1 after binding with cytochrome c.
  • recruits initiator caspase-9 proteins, which activate the caspase cascade.
A

apoptpsome

137
Q

The apoptosome recruits __, which activate the caspase cascade.

A

initiator caspase-9 proteins

138
Q

a major class of intracellular regulators of the intrinsic apoptosis pathway, controlling the release of cytochrome c and other mitochondrial proteins into the cytosol.

A

Bcl2 family

139
Q

What are the two types of Bcl2 family proteins? (2)

A
  • Antiapoptotic
  • pro-apoptotic proteins
140
Q

Name two antiapoptotic Bcl2 family proteins. (2)

A
  • Bcl2
  • BclXL
141
Q

What are the two categories of pro-apoptotic Bcl2 family proteins? (2)

A
  • Effector Bcl2 family proteins
  • Bh3-only proteins.
142
Q

What triggers the activation of the intrinsic pathway of apoptosis?

A

apoptotic stimulus

143
Q

After the intrinsic pathway is activated, what aggregate to form oligomers in the mitochondrial outer membrane, leading to the release of cytochrome c?

apoptosis

A

Bcl2 family proteins

144
Q

Which proteins are the main effectors of the intrinsic pathway?

apoptosis

A
  • Bax (in the cytosol)
  • Bak (in the mitochondrial outer membrane)
145
Q

They are located on the cytosolic surface of the outer mitochondrial membrane and prevent inappropriate release of intermembrane proteins by binding to and inhibiting pro-apoptotic Bcl2 family proteins.

A

anti-apoptotic proteins (like Bcl2 and BclXL)

146
Q
  • promote apoptosis mainly by inhibiting anti-apoptotic Bcl2 family proteins, enabling the aggregation of Bax and Bak on the mitochondria.
  • triggers the instrincic pathway by enabling Bax and Bak aggregation on the mitochondrial surface, they trigger the release of intermembrane mitochondrial proteins that induce apoptosis.
A

BH3-only proteins

147
Q

In response to DNA Damage, the tumor suppressor protein __ accumulates and activates the transcription of genes encoding __, such as __ and __, which trigger the intrinsic pathway.

A
  • p53
  • BH3-only proteins
  • Puma
  • Noxa
148
Q
  • proteins that prevent apoptosis by binding and inhibiting activated caspases; they were first identified in insect viruses.
  • contain one or more __ domains, which enable them to bind and inhibit activated caspases.
A

inhibitors of apoptosis (IAPs)
- BIR (baculovirus IAP repeat)

149
Q
  • In Drosophila, this contain an IAP-binding domain that binds to the BIR domain of IAPs, preventing them from inhibiting caspases and promoting apoptosis.
  • It is also released from the mitochondrial intermembrane space upon activation of the intrinsic pathway, blocking IAPs in the cytosol and promoting apoptosis.

Give 3 of this

A

Anti-IAPs
- Reaper
- Grim
- Hid

150
Q

can inhibit apoptosis, promoting cell survival.

A

Extracellular signals

151
Q

are produced in excess, and they compete for limited amounts of survival factors; those that receive enough survival signals live, while others die.

A

Nerve cells/Neurons

152
Q

In the developing nervous system, the number of surviving neurons is automatically adjusted to be appropriate for the number of __ they connect with.

A

target cells

153
Q
  • What binds to cell-surface receptors, activating intracellular signaling pathways that suppress the apoptotic program?
  • They regulate members of the __ family of proteins.
  • They stimulate the synthesis of __ proteins.
  • They inhibit the function of __ proteins such as Bad.
  • They phosphorylate and inactivate __ like Hid, enabling IAP proteins to suppress apoptosis.

apoptosis

A
  • survival factors
  • Bcl2
  • anti-apoptotic Bcl2
  • pro-apoptotic BH3-only
  • anti-IAP proteins
154
Q

During cell death, Apoptotic cells and their fragments remain intact and are efficiently __ by neighboring cells.

A

phagocytosed

155
Q

Chemical changes on the surface of the apoptotic cell recruit __ trigger the recruitment of phagocytic cells to apoptotic cells

A

phagocytic cells

156
Q

normally resides in the inner leaflet of the lipid bilayer, flips to the outer leaflet in apoptotic cells, signaling for phagocytosis.

A

Phosphatidylserine

157
Q

Healthy cells express __ that interact with __ on macrophages, blocking phagocytosis of healthy cells.

Macrophages distinguish between healthy and apoptotic cells

A
  • signal proteins
  • inhibitory receptors
158
Q

Both __ and __ apoptosis can lead to various diseases, including cancer and autoimmune disorders.

A
  • excessive
  • insufficient
159
Q

Cells die by necrosis as a result of ischemia during __ or __.

A
  • heart attacks
  • strokes
160
Q

Inactivation of the genes encoding the __ or the __ can prevent normal lymphocyte death, leading to accumulation and autoimmune diseases.

A
  • Fas death receptor
  • Fas ligand
161
Q

__ apoptosis in tumors allows cancer cells to regulate their apoptotic program abnormally, contributing to tumor growth.

A

Decreased

162
Q

A chromosome translocation causing excessive production of the Bcl2 protein is associated with B cell lymphoma, inhibiting apoptosis.

A

Bcl2 gene

163
Q

The regulation of apoptosis affects sensitivity to __ by inhibiting __, cancer cells can decrease their sensitivity to anticancer drugs, making treatment less effective.

A
  • anticancer drugs
  • apoptosis
164
Q

What percentage of human cancers involve mutations in the gene encoding the tumor suppressor protein p53?

A

50%

165
Q

Mutated __ can no longer promote apoptosis or cell-cycle arrest in response to DNA damage, allowing cancer cells to survive and proliferate despite DNA damage.

A

p53

166
Q

drugs that are small chemicals that interfere with the function of __, promoting cell death.

A

anti-apoptotic Bcl2 family proteins

Cell and Molecular Biology (20 decks)

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