Final Exam - Programmed Cell Death and Development

Question 1

What is a caspase?

Answer 1

a cysteine-dependent asparate-directed proteases

Question 2

What is the function of a caspase?

Answer 2

degrade proteins to ensure cellular components are degraded in a controlled and regulated way

Question 3

What are caspases important in?

Answer 3

development and throughout life to maintain homeostasis

Question 4

What are the 2 classes of caspases?

Answer 4

initiator caspases and other

Question 5

What is the function of an initiator capsase?

Answer 5

once activated, they produce a chain reaction (cascade-style chain of events) which activates executioner caspases

Question 6

What do the executioner caspases do?

Answer 6

degrade cellular components which allow the morphological changes to the cell that result in apoptosis

Question 7

What is the function of ‘other’ caspases?

Answer 7

they require a cysteine to be in the active site and will cleave the protein to an aspartic acid residue

Question 8

Discuss the mechanisms of caspase activation.

Answer 8

• Initiator caspase starts out as separate, inactive monomers
• an apoptotic signal acts on adapter proteins, which celaves and dimerizes the initiator caspase
• the activated initiator caspase cleaves executioner caspase to activate it
• downsteam cleavage of other substrates (cascades)
• result is apoptosis

Question 9

What is the extrinsic apoptosis pathway known as?

Answer 9

the death receptor pathway

Question 10

What does the extrinsic pathway use for activation?

Answer 10

a ligand and a receptor

Question 11

What is the extrinsic pathway mediated by?

Answer 11

T-cells

Question 12

Describe an example of the Extrinsic pathway.

Answer 12

• Fas ligand on T-cell binds to Fas death receptor
• Formation of DISC(death-inducing signaling complex) on cell interior
• Activation of caspase 8
• Activationof executioner caspases
• apoptosis

Question 13

What is the intrinsic apoptosis pathway activated by?

Answer 13

-intracellular factors which cause cytochrome C leakage into the cytoplasm from the mitochondria

Question 14

What are the triggering factors of the intrinsic pathway?

Answer 14

• oxidative stress
• hypoxia
• nutrient deprivation

Question 15

What happens when cytochrome C leaks?

Answer 15

• activation of cascade of various factors
• activation of a variety of caspases
• apoptosis

Question 16

What does too little proliferation lead to?

Answer 16

microphthalmia

Question 17

What are the side effects of microphthalmia?

Answer 17

‘small eye’ phenotype; can be genetic, infectious, and environmental

Question 18

What does too much proliferation lead to?

Answer 18

double muscle phenotype

Question 19

What happens with the double muscle phenotype?

Answer 19

myostatin inhibits proliferation for muscle to develop normally

Question 20

What is special about belgian blue cattle?

Answer 20

they have more myocytes than normal

Question 21

What is syndactyly?

Answer 21

the fusion of digits caused by the incomplete apoptosis of interdigital cells between developing digits

Question 22

What is the role of apoptosis in survival?

Answer 22

target cells will get survival signals that inhibit apoptosis

Question 23

Proliferation and apoptosis is needed for survival, what keeps them in check?

Answer 23

factors that inhibit and factors that stimulate