Unit 3: Cell ageing Flashcards
What is ageing ?
The collection of changes that render humans/mammals being progressively more likely to die
What are the 3 theories of ageing ?
- Genetics
- Wear and tear
- Environment
Describe the genetic theory of ageing
It says that when we are born our cells are already programmed to die by a certain age. Genes are associated with lifespan
Describe the wear and tear theory of ageing
Organisms have to find a balance between energy put into reproduction and energy put into maintenance. More maintence the longer you live.
Describe the environment theory of ageing
Environmental factors increase vulnerability of disease at an old age. Evidence that dietary restriction can slow down ageing
What is the ‘disposable soma’ theory ?
- That the force of natural selection declines with age
- Antagonistic pleiotropy
- Acquisition of greater longevity comes at a cost
What are the 3 ageing process ?
- Cellular senescence
- Oxidative stress
- Gene expression
What is the hayflick limit ?
The maximum number of times a cell can reproduce itself
What happens to telomeres when cells divide ?
Part of the telomeres is lost from the end of the chromosome (Cut short)
What does telomerase do ?
Allows telomeres to remain at a constant length
Where is telomerase most actively expressed ?
In most cancers, this allows cells to be immortal
What is Werners syndrome ?
Genetic disorder where death occurs prematurely at the average age of 47
What is ROS and where does it come from ?
- Reactive oxygen species
- Originates from exogenous sources such as UV
