NEET BIOLOGY

Detailed explanation-1: -But some cells, such as skin cells or blood cells are dividing all the time. When cells become damaged or die the body makes new cells to replace them. This process is called cell division. One cell doubles by dividing into two.

Detailed explanation-2: -The epidermis is continually renewed from stem cells, with a turnover time, in humans, of the order of a month. Stem cells, by definition, are not terminally differentiated and have the ability to divide throughout the lifetime of the organism, yielding some progeny that differentiate and others that remain stem cells.

Detailed explanation-3: -About 330 billion cells are replaced daily, equivalent to about 1 percent of all our cells. In 80 to 100 days, 30 trillion will have replenished-the equivalent of a new you.

Detailed explanation-4: -During mitosis one cell? divides once to form two identical cells. The major purpose of mitosis is for growth and to replace worn out cells.

Detailed explanation-5: -We can connect this lifetime to the fact calculated in the vignette on “How many cells are there in an organism?” that there are about 3×1013 red blood cells to infer that about 100 million new red blood cells are being formed in our body every minute!