Tag: biology

• Ageing is a complex process that varies as to how it affects different people and even different organs. Most gerontologists (people who study aging) feel that aging is due to the interaction of many lifelong influences. These influences include heredity, environment, culture, diet, exercise and leisure, past illnesses, and many other factors.
• Morphological changes during aging include the number of taste bud decreases, Decreased rate of cardiovascular functions and The reduction in the number of nephrons.
• So, the correct answer is 'All the above'.

According to immunity theory, 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 ‘Degeneration of thymus’.

• Ageing is a complex process that varies as to how it affects different people and even different organs. Most gerontologists (people who study aging) feel that aging is due to the interaction of many lifelong influences. These influences include heredity, environment, culture, diet, exercise and leisure, past illnesses, and many other factors.
• Lipofuscin (age pigment) is a brown-yellow, electron-dense, autofluorescent material that accumulates progressively over time in lysosomes of postmitotic cells, such as neurons and cardiac myocytes. It causes ageing by the degradation of phospholipid of the plasma membrane.
  
• So, the correct answer is 'degradation of phospholipid of plasma membrane'.

• The thymus gland secretes a peptide hormone called Thymosin. Thymosin plays a major role in the differentiation of T-lymphocytes, which provide cell-mediated immunity. In addition, thymosins also promote the production of antibodies to provide humoral immunity.
• The thymus gland is degenerated in old individuals resulting in a decreased production of thymosins. As a result, the immune responses of old persons become weak.
• Hence Thymosin hormone controls the biological clock of ageing by promoting immunity in adult and by degeneration in older individuals.
  
• So, the correct answer is 'Thymosin'.

• Scab is a collection of dried blood cells and serum and sits on top of the skin surface.
• The outermost layer of our skin is composed of epithelial cells. As wounds heal, epithelial cells regenerate across the wound surface from the edges to close the wound. 
  
• The Epidermal growth factor induces the epithelial cells below the scab to undergo mitosis and facilitates closure of the wound.
• So, the correct answer is 'Epidermal growth factor'.

When ageing is progressing in the human body, different types of oxidising enzymes activity increases because of decreased rate of metabolism.

So, the correct option is ‘Malate dehydrogenase’.