Introduction

Question 1

define senescence

Answer 1

the decline of fitness components of an individual with increasing age, owing to internal deterioration

Question 2

define the rate of aging and life expectancy

Answer 2

rate of aging is unchanged for thousands of years whereas life expectancy can be affected by a number of things

Question 3

what are 3 non-aging organisms

Answer 3

bristlecone pine, bacteria, red sea urchin

Question 4

what are the 2 modern biological theories of aging

Answer 4

the programmed theory and damage theory

Question 5

describe the mutation accumulation evolutionary theory of aging

Answer 5

an early mutation causes a strong force of selection but late acting mutations occur after genes have been passed on to offspring so late onset diseases are more common

Question 6

describe the antagonistic pleiotropy evolutionary theory of aging

Answer 6

some genes may have beneficial effects in early life but negative effects later in life and benefits outweigh the positives. e.g. testosterone which controls sex drive, sperm production and muscle mass but can lead to prostate issues in later life

Question 7

describe the disposable soma evolutionary theory of aging

Answer 7

organisms have a limited amount of energy that has to be divided between reproductive activities and non reproductive activities and so bodies degrade once past the reproductive peak

Question 8

describe the rate of living mechanistic theory of aging

Answer 8

duration of life is dependant on exhaustion of a fixed quantity of a vital substance at a rate proportional to the metabolic rate

Question 9

describe the hayflicks limit mechanistic theory of aging

Answer 9

a cell is able to divide a limited number of times- 50-70 times before death= hay flicks limit

Question 10

describe the mitochondrial free radical mechanistic theory of aging

Answer 10

cells produce free radicals which can cause damage to macromolecules- lifespan inversely proportional to metabolic rate

Question 11

how can genes involved in aging be determined

Answer 11

select for and isolate mutants which outlive their life expectancy/with altered rates of aging and map, clone and sequence the genes

Question 12

which models are used in studying aging and why

Answer 12

c.elegans, drosophila, yeast, mice and rats
they have short life spans, easily maintained, less complex genome than humans, model organisms can be genetically engineered

Question 13

why is c.elegans particularly good aging model

Answer 13

each cell has been mapped from embryonic stage to later life, the nervous system is well studied and you can see signs of waging incl: wrinkly skin, reduced movement, reduced feeding, reduced fertility