Lec 42

Question 1

Cell necrosis

Answer 1

Injured cell ruptures and damages neighboring cells

Question 2

Apoptosis

Answer 2

Cells that are no longer needed are dismantled

Question 3

Preparation for apoptosis

Answer 3

Procaspases are present but inactive in the cell

Bcl2 protects mitochondria

DNases are inactive in nucleus

Phosphatidylserines are hidden in membrane

Question 4

Step 1 of apoptosis

Answer 4

The trigger

Question 5

Triggers for apoptosis

Answer 5

Damage to mitochondria

Damage to DNA

Absence of survival signals

Death signal from a T cell (type of WBC)

Question 6

Survival signalsT

Answer 6

Many neurons are released to a target cell

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

Question 7

T cells

Answer 7

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

contact dependent signalling

Question 8

Activation of procaspases

Answer 8

A signal comes along and makes active caspases which cause apoptosis

Question 9

Procaspases are activated by

Answer 9

Proteolysis

cutting of certain pieces and rearrangement of others

Question 10

Adaptor protein

Answer 10

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

Question 11

Healthy mitochondria

Answer 11

Healthy inner and outer membrane

Cytochrome c is inside the mitochondria

Question 12

If mitochondria is damage

Answer 12

cytochrome c is released to signal apoptosis

Procaspases are brought together and made into caspases

Question 13

DNA damage leads to

Answer 13

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

Question 14

UV can cause

Answer 14

DNA damage

Question 15

Absence of survival signals leads to

Answer 15

no Bcl2 is made

Cyt c released

same as before

Question 16

T cells have

Answer 16

Fas ligands which attach to Fas receptor on infected cells

Question 17

Death signal from a T cell leads to

Answer 17

Fas ligands attaching to Fas receptor

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

Question 18

Caspase cascade

Answer 18

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

Chain reaction

Question 19

Caspases also

Answer 19

Cleave target proteins

Question 20

Cell destruction

Chromosome destruction

Answer 20

Caspases indirectly activate DNase by destroying its inhibitor

Destroying the chromosomes

DNase chops between every histone (about every 200bp)

Question 21

Experiment apoptosis

Answer 21

Adding DNA repair enzymes and fluorescently labelled DNA nucleotides

Them binding to the apoptosis cells makes them fluoresce

Experiment called TUNEL

Question 22

Madagascar Laceleaf

Answer 22

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

Question 23

Nuclear envelope being dismantled

Answer 23

Caspases directly destroy Nuclear Lamins

cells then round up and become apoptotic bodies

Question 24

Caspases target

Answer 24

Everything (nucleus and everything the cell is connected to)

Question 25

What happens to the little of pieces of cells (apoptotic bodies)

Answer 25

Phagocytosis by either neighbor cells or macrophages

Question 26

Non-professional phagocytes

Answer 26

Neighboring cells

Question 27

Professional phagocytes

Answer 27

Macrophages

Question 28

Phosphatidylserine

Answer 28

Move to outer side of membrane from the inner
to tell other cells to consume the apoptotic bodies

Question 29

Scramblase

Answer 29

Scramble Phosphatidylserine

Question 30

Flipase

Answer 30

Flip Phosphatidylserine

Question 31

Phosphatidylserine moving to the outside is done by

Answer 31

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

Question 32

Why chop up DNA

Answer 32

To make apoptosis irreversible

To make apoptotic bodies safe to eat (destroy viruses)