The first living things on Earth, single-celled micro-organisms or microbes lacking a cell nucleus or cell membrane known as prokaryotes, seem to have first appeared on Earth almost four billion years ago, just a few hundred million years after the formation of the Earth itself.
Phagocytosis of microbes by macrophages is enhanced by both the binding of antibodies to the surface of microbes & antibody-mediated opsonization of microbes
What is the function of phagocytosis?
Phagocytosis is the cellular process through which particles bigger than 0.5 m in diameter, such as bacteria, foreign substances, and apoptotic cells, are ingested and eliminated.
- Phagocytosis is found in many different types of cells and is hence an important step for tissue homeostasis.
- However, only specialized cells known as professional phagocytes are capable of high-efficiency phagocytosis.
- Among these specialized cells are macrophages, neutrophils, monocytes, dendritic cells, and osteoclasts.
Phagocytosis occurs in four stages:
I identification of the particle to be swallowed,
ii) activation of the internalization process,
iii) development of a specialized vacuole known as a phagosome,
iv) maturation of the phagosome to turn it into a phagolysosome.
Hence, the correct option is A
Learn more about phagocytosis here,
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Question:
What is eye lens?
Answer:
lens, in anatomy, a nearly transparent biconvex structure suspended behind the iris of the eye, the sole function of which is to focus light rays onto the retina.
Question:
How is its shape and size cchange.
Answer:
The Lens Changes Shape to Focus Near Objects. Light rays from objects that are close to the eye are not parallel.
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