Lec 42 Flashcards

1
Q

Cell necrosis

A

Injured cell ruptures and damages neighboring cells

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2
Q

Apoptosis

A

Cells that are no longer needed are dismantled

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3
Q

Preparation for apoptosis

A

Procaspases are present but inactive in the cell

Bcl2 protects mitochondria

DNases are inactive in nucleus

Phosphatidylserines are hidden in membrane

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4
Q

Step 1 of apoptosis

A

The trigger

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5
Q

Triggers for apoptosis

A

Damage to mitochondria

Damage to DNA

Absence of survival signals

Death signal from a T cell (type of WBC)

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6
Q

Survival signalsT

A

Many neurons are released to a target cell

When one reaches the target, the target releases survival signals indicating that the neurons works

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7
Q

T cells

A

Sees a virus in a an adjacent cell and sends a death signal

contact dependent signalling

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8
Q

Activation of procaspases

A

A signal comes along and makes active caspases which cause apoptosis

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9
Q

Procaspases are activated by

A

Proteolysis

cutting of certain pieces and rearrangement of others

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10
Q

Adaptor protein

A

brings procaspases together and causes proteolysis to all of them to activate them

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11
Q

Healthy mitochondria

A

Healthy inner and outer membrane

Cytochrome c is inside the mitochondria

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12
Q

If mitochondria is damage

A

cytochrome c is released to signal apoptosis

Procaspases are brought together and made into caspases

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13
Q

DNA damage leads to

A

p53 which leads to creation of PUMA

PUMA inhibits Bcl2
Bcl2 protects the mitochondria so its inhibition causes Cytochrome c to be released which leads to caspases like before

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14
Q

UV can cause

A

DNA damage

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15
Q

Absence of survival signals leads to

A

no Bcl2 is made

Cyt c released

same as before

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16
Q

T cells have

A

Fas ligands which attach to Fas receptor on infected cells

17
Q

Death signal from a T cell leads to

A

Fas ligands attaching to Fas receptor

This leads to Procaspases being brought together and the rest is the same

18
Q

Caspase cascade

A

Once one caspase is activated they activated all the other 6 types of procaspases

Chain reaction

19
Q

Caspases also

A

Cleave target proteins

20
Q

Cell destruction

Chromosome destruction

A

Caspases indirectly activate DNase by destroying its inhibitor

Destroying the chromosomes

DNase chops between every histone (about every 200bp)

21
Q

Experiment apoptosis

A

Adding DNA repair enzymes and fluorescently labelled DNA nucleotides

Them binding to the apoptosis cells makes them fluoresce

Experiment called TUNEL

22
Q

Madagascar Laceleaf

A

Grows in streams with water pushing against it

Plant has holes in the leaf to allow it to stand upright which is done by apoptosis

23
Q

Nuclear envelope being dismantled

A

Caspases directly destroy Nuclear Lamins

cells then round up and become apoptotic bodies

24
Q

Caspases target

A

Everything (nucleus and everything the cell is connected to)

25
What happens to the little of pieces of cells (apoptotic bodies)
Phagocytosis by either neighbor cells or macrophages
26
Non-professional phagocytes
Neighboring cells
27
Professional phagocytes
Macrophages
28
Phosphatidylserine
Move to outer side of membrane from the inner to tell other cells to consume the apoptotic bodies
29
Scramblase
Scramble Phosphatidylserine
30
Flipase
Flip Phosphatidylserine
31
Phosphatidylserine moving to the outside is done by
Neither flipase or scramblase Instead exocytosis and endocytosis is done poorly and randomly to scramble the Phosphatidylserines and put some of them of the outside
32
Why chop up DNA
To make apoptosis irreversible To make apoptotic bodies safe to eat (destroy viruses)