Death

Question 1

What is the biochemical view of ageing?

Answer 1

That it is a highly regulated process that may determine reproductive life

Question 2

What is the biological view of ageing?

Answer 2

That it is merely a consequence of having passed reproductive age

Question 3

What is mitochondria the site of?

Answer 3

Oxidative metabolism

Question 4

What are free radicals of oxygen?

Answer 4

Very reactive molecules which can react with every cellular component e.g. DNA, proteins and lipids

Question 5

How are free radicals of Oxygen formed?

Answer 5

They are byproducts of oxidative phosphorylation (i.e. aerobic respiration) in the mitochondria

Question 5

How are free radicals of Oxygen formed?

Answer 5

They are byproducts of oxidative phosphorylation (i.e. aerobic respiration) in the mitochondria

Question 6

What can free radicals of oxygen cause?

Answer 6

Mutations

Question 7

What is true of the leak of free radicals?

Answer 7

The rate is proportional to metabolism (almost)

Question 8

What do free radicals act as a signal for?

Answer 8

They act as a signal to increase the expression of more respiratory chain enzymes.

This adds balance and a lower probability of free radicals escaping

Question 9

What happens if the increase of respiratory chain enzymes cannot fix the problem of free radicals?

Answer 9

The mitochondria are stimulated to divide, and the % of impaired mitochondria become more important.

= clonality

Question 10

What is the metabolic rate of Drosophilia (fruit flies) linked to?

Answer 10

Ambient temperature

A 10°C rise in temperature = metabolic rate doubles = lifespan halves

Question 10

What is the metabolic rate of Drosophilia (fruit flies) linked to?

Answer 10

Ambient temperature

A 10°C rise in temperature = metabolic rate doubles = lifespan halves

Question 11

What is true of Salvelinus fontinalis (brook trout) lifespan/metabolic rate?

Answer 11

Lifespan not normally >6 years

However – populations transferred to cold, resource poor lakes live at leats 24 years = delayed maturation

Question 12

What is an example of an ‘immortal’ cell?

Answer 12

Cancer

Question 13

What is the Warburg effect?

Answer 13

Cancer cells tend not to use their mitochondria.

Question 14

What is true of neuronal mortality?

Answer 14

Neurons (and the information contained in the synapses they make) may be irreplaceable

Question 15

What is the hay flick limit?

Answer 15

The number of times that normal human embryonic cells can divide before they succumb to senescence (death).

40-60 times

Question 16

What percentage of neutrons die before we are bon?

Answer 16

80%

Question 17

What ways doing cells die>

Answer 17

Apoptosis, autphagy and necosis

Question 18

What is apoptosis?

Answer 18

Programmed cell death – highly regulated natural process

Question 19

How many cells die via apoptosis?

Answer 19

c. 10 billion cells/day
c. 416 million/hour

Question 20

What is autophagy in terms of cell death?

Answer 20

Self-eating cells – highly regulated catabolic process

Question 21

What is necrosis in terms of cell death?

Answer 21

Unregulated

No chemical/ immune signals

Acute cellular injury

Question 22

What causes cells to die via autophagy?

Answer 22

Periods of stress

e.g. nutrient scarcity and ATP is needed for apoptosis

Question 23

What is the role of apoptosis?

Answer 23

Removal of damaged or old cells

Removal of cells that are not needed

Removal of cells that have lost control

Question 24

What is the role of caspases in apoptosis?

Answer 24

They are a family of cysteine proteases that serve as primary effectors during apoptosis to dismantle most cellular structure.