A cell is the basic unit of life. Cells vary tremendously in size — from the tiniest bacteria to enormously large single cells. This is one of the most popular biology GK questions asked in competitive exams.
The smallest known cells in the world are certain species of the bacterium Mycoplasma, which lack a cell wall. They are about 0.1 to 0.3 micrometres in diameter — roughly 1000 times smaller than a human egg cell.
The female ovum (egg cell) is the largest cell in the human body.
Smallest human cell: The male sperm cell (specifically its head) is considered the smallest human cell.
The Ostrich egg is the largest single cell in the world.
Longest cell in the human body: While the ovum is the largest by volume/diameter, the neurons (nerve cells) can be the longest cells. Motor neurons that run from the spinal cord to the toes can be over 1 metre long.
Yes, barely. The human ovum (egg cell) is approximately 0.1 mm in diameter, which is right at the limit of human visual resolution. Under good lighting conditions, it can technically be seen without a microscope, making it unique among human cells.
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