Question

Ageing is due to accumulation of harmful protein. The theory is
A. Free radical
B. Cross linking
C. Error catastrophe
D. All the above

Answer 1

Hint: Ageing is a physiological process of a series of changes an organism undergoes towards the decline in the physical and biological functions. The change is in the cellular a well as molecular level. It is a gradual process which starts at adulthood.

Complete Answer:
There are several theories which describe the reason for the occurrence of aging.
1. Free radical theory - It says that aging happens due to the accumulation of reactive oxygen species which causes damage. The ageing is the result of oxidative damage.
2. Cross linking theory - It is also called the glycosylation theory. The accumulation of cross linked protein slows down the body’s physiological process and leads to damage of cells and tissues. This results in aging.
3. Error catastrophe theory - It says that the accumulation of errors in the essential cellular molecules that leads to catastrophic level which does not permit cellular survival. This error leads to synthesis of harmful proteins.

Hence, the correct answer is C. Ageing is due to accumulation of harmful protein. The theory is error catastrophe theory.

Note: The ageing is majorly caused due to oxidative stress, glycosylation, mutations, accumulation of proteins. It leads to gradual damage to the structure and function of the cells, tissues and organs. Bacteria, some plants, simple animals and fungi are biologically immortal.