Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physiology > Oncogenes and apoptosis > Flashcards

Oncogenes and apoptosis Flashcards

1
Q

what is apoptosis?

A

Physiologica cell death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name 4 situations when the apoptosis of cells occurs

A

Redundant cells
Damaged cells
Obsolete cells
Harmful cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

In what physiologic state is the balance of mitosis and apoptosis equal?

A

Homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In what physiologic state is the rate of mitosis too high compared to apoptosis?

A

Neoplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In what physiologic state is the rate of apoptosis too high compared to mitosis?

A

Degeneration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the difference between apoptosis and necrosis?

A

Apoptosis is a “clean” cell death

necrosis is cell death with inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the steps of apoptosis

A

Cell shrinks
Cell breaks down in to apoptotic bodies
Apoptotic bodies are phagocytosed by neighboring cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Does apoptosis induce inflammation?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the steps of necrosis

A

Cell swells

Plasma membrane of cell breaks and contents flow out

Cell is lysed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 death triggers of apoptosis?

A

Death triggers:
Lack of survival factors, growth factors or hormones

DNA damage

Death ligands and receptors

Oxidative stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What enzyme is used for the initiation of the death receptor pathway?

A

Capase 8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What enzyme is used for the initiation of the mitochondrial pathway?

A

Capase 9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the execution stage of apoptosis

A

Integration capases (8,9) activate capases 3,6 and 7

Capase 3,6,7 activate proteases and endonucleases that cleave cytoskeleton and DNA, respectively

Cleavage of cytoskeleton and DNA leaves fragments tagged for phagocytosis by macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the chopping machine of the apoptosis pathway?

A

Capase 3,6,7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the Fas-FasL Death receptor pathway

A

Fas ligand binds to Fas receptor and associates with Fas Associated Death Domain and procapase 8 to form the Death Inducing Signaling complex

Capase 8 is released from DISC

Capase 8 activates capase 3,6,7 to execute apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the mitochondrial death pathway via Bax

A

Fas ligand binds to Fas receptor and associates with Fas Associated Death Domain and procapase 8 to form the Death Inducing Signaling complex

Capase 8 is released from DISC

Capase 8 activates capase 3,6,7 to execute apoptosis

Transcription of Bax: apoptosis signaling molecule

Bax enters creates pore in mitochondrial membrane

cytochrome c enters cytoplasm and associates with apoptosis protease activating factor and procapase 9

Capase 9 is released from apoptosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What leads to transcription of p53?

A

Moderate cell damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the function of p53?

A

Tumor suppressor

Induction of Bax transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is apoptosis associated with bcl2?

A

bcl2 is an anti-apoptotic molecule

20
Q

What 3 functions does the Fas-FasL pathway participate in?

A

Inflammation
Termination of immune response (autocrine suicide T-cells)
Cancer cells express FasL to promote cytotoxic T-cells

21
Q

What is autocrine suicide & juxtracrine fratricide?

A

During inflammatory conditions, cells express FasL which causes autocrine suicide or juxtracrine fraticide

22
Q

Describe the pathway of juxtracrine fraticide

A

DISC complex forms on cell

Capase 8 is activated and FasL is activated to go to adjacent cell

23
Q

How does failure of the FasL-Fas system lead to autoimmune diseases?

A

Lymphocytes fail to die

Rampant Ab production

24
Q

What is a proto-oncogene?

A

Genes that code for the signaling of molecules that are involved in regulation of cell growth and prevention of apoptosis

25
What are oncogenes?
Mutated or overexpressed proto-oncogenes Cause cancer
26
What causes the mutation of proto-oncogenes to oncogenes?
Spontaneous development | Retro-viruses
27
Name 2 tumor suppressor genes
p53, pRB
28
Describe how the accumulation of multiple mutations leads to cancer
Loss of 2 plasma-membrane bound signaling molecules Mutation of ras (cell growth gene) leads to alternative cell growth Alternative cell growth forms adenoma 2 more plasma-membrane signaling molecules are lost More proliferation of alternative cells homozygous loss of p53 Invasive carcinoma
29
Why is the proto-oncogene RAS important?
Intrinsic GTPase activity turns RAS (transcription) off
30
What happens if the proto-oncogene RAS is mutated to the oncogene RAS
oncogene RAS lacks GTPase activity Cannot terminate proliferation signals Cancer
31
What is the function of p53 on a cell with minor damage? Major damage?
If damage was minor, p53 halts cell cycle until DNA is repaired If damage was major, p53 halts cell cycle and induces apoptosis via BAX
32
What is the result of p53 being inhibited?
Cell cycle does not halt and damaged DNA is proliferated May cause carcinomas
33
Name the growth factor oncogene. Type of cancer?
sis, human cancer
34
Name the growth factor receptor oncogene. Type of cancer?
erb B, canine mammary carcinomas
35
name the signal transduction protein oncogene. Type of cancer?
ras, src | many cancers
36
Name the nuclear transcription factor oncogene. Type of cancer?
myc, jun, fos | Human and animal cancers
37
Name the cell cycle regulator oncogene. Type of cancer?
Cyclin D | Breast cancer
38
Name the tumor suppressor gene oncogenes. Type of cancers?
pRB, p53 Retinoblastomas Osteosarcomas
39
Name the anti-apoptosis oncogene. Type of cancer?
bcl-2 | Leukemia
40
Which oncogenes were discovered due to their presence in retoviruses?
sis, erb B, ras, src, myc, fos, jun
41
Retroviruses cause the transformation of cells. Why is this important in cancer?
Normal cells inhibit growth after contacting neighboring cells Transformed cells do not inhibit growth after contacting neighboring cells
42
What is unique about retroviruses?
Reverse transcription (DNA from RNA)
43
Describe how retroviruses infect hosts
Viruses binds to membrane and capsid is endocytosed Capsid dissolves and viral RNA is transcribed into viral DNA viral DNA is integrated in to host's DNA host genome will transcribe and translate viral RNA viral RNA is assembled in to a capsid enveloped in transcribed viral envelopes are exocytosed by the cell
44
What is the rous sarcoma virus?
Virus carries large portion of host genome and relies on helper viruses for own replication If passenger gene is an oncogene, can cause cancer
45
Describe how a virus containing the oncogene RAS would cause cancer
Viral RNA is transcribed to DNA Oncogene RAS is transcribed Oncogene RAS cannot turn off cell signal proliferation

Physiology (45 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions