Which vitamin can be synthesized by the human skin on exposure to sunlight? MCQ with Answer and Explanation

Explanation:
Mitochondria are known as the powerhouse of the cell because they are the site of aerobic respiration and ATP production. They are semi-autonomous because they possess their own circular DNA, RNA, and 70S ribosomes, allowing them to synthesize some of their own proteins and replicate independently of the nucleus.

Explanation:
Rennin (chymosin) is a proteolytic enzyme found in the gastric juice of young mammals; it curdles milk by converting soluble caseinogen into insoluble casein, slowing its passage and allowing pepsin to digest it. Pepsin is the main adult protease, trypsin is pancreatic, and lipase digests fats. Rennin is now produced biotechnologically for cheese making.

Explanation:
The chemical evolution theory, also known as the biochemical theory of the origin of life, was proposed independently by Alexander Oparin (1924) and J.B.S. Haldane (1929). They proposed that life originated from pre-existing non-living organic molecules (like RNA, proteins, lipids) through a series of complex chemical reactions in the primitive reducing atmosphere of Earth.