Tag: biology

A. Actin - plays an important role in embryogenesis, the healing of wounds and the invasivity of cancer cells.

B. Myosin – plays an important role in muscle contractions and  a variety of movements of nonmuscle cells, including cell division,

C. Collagen – plays a significant role in ageing.

D. Elastin - plays an important role in the biomechanical function of vital body tissues and organs such as the heart, lungs, skin and the vocal folds.

So, the correct option is ‘Collagen’.

A. Somatic mutation theory - posits that the accumulation of mutations in the genetic material of somatic cells as a function of time results in a decrease in cellular function.

B. Programmed senescence theory - refers to the idea that senescence in humans and other organisms is purposely caused by evolved biological mechanisms in order to obtain an evolutionary advantage.

C. wear and tear theory - asserts that the effects of ageing are caused by progressive damage to cells and body systems over time. Essentially, our bodies "wear out" due to use. Once they wear out, they can no longer function correctly.

D. Immunological theory - asserts that the process of human ageing is, in fact, a mild and generalized form of the prolonged auto-immune phenomenon.

So, the correct option is ‘Programmed senescence theory’.

Ageing starts with the disappearance of thymus according to immunity theory . Thymic involution (shrinking of the thymus with age) is believed to be the main age-related change in the immune system, and this alteration begins after puberty.

So, the correct option is ‘thymus gland’.

Increase in the age of the persons is called ageing. In this, loss or decrease of physical, physiological, behavioural activities takes place. The decrease in wear and tear, neurohormonal changes, the rate of metabolism, somatic mutations take place. Replacement of organs does not take place in ageing.

So, the correct option is ‘Epimorphosis’.

Immunity theory is the widely accepted theory for ageing. The immune system is programmed to decline its functions over time, and this fact is the main cause of aging. Thymic involution (shrinking of the thymus with age) is believed to be the main age-related change in the immune system, and this alteration begins after puberty.

So, the correct option is ‘Non functioning of thymus gland’.

A. Error and damage theories - emphasize environmental assaults to living organisms that induce cumulative damage at various levels as the cause of aging.

B. Hormonal theory - hormones or reduced production of hormones might cause aging has also led some to believe that they could be an anti-aging elixir. 

C. Immunological theory - asserts that the process of human aging is, in fact, a mild and generalized form of prolonged auto-immune phenomenon.

D. Programmed senescence theory - refers to the idea that senescence in humans and other organisms is purposely caused by evolved biological mechanisms in order to obtain an evolutionary advantage.

So, the correct option is ‘Error and damage theories’.

Extensor muscles. Attached to the back of the spine, these muscles allow us to stand and lift objects. They include the large muscles in the lower back (erector spinae), which help hold up the spine, and gluteal muscles.

The stapedius muscle, which is innervated by the facial nerve (cranial nerve VII), is the smallest of all skeletal muscles.