Question

!!! One Medal Question !!!
- Describe the composition of the plasma membrane

Answer 1

it controls which substances are to enter or leave the cell, transfers chemical messages from the outside of the cell to the inside and keeps the cell contents in place.

the cell membrane is composed of mainly lipids and protein. Because it is mostly lipids, it only allows lipid soluble substances such as oxygen, carbon dioxide and steroids to go through. water soluble substances , such as glucose, amino-acids ion and water need the help of these various proteins for transport.

structure-
two layers of phospholipid molecules self assemble so that their water-soluble/ hydrophilic heads form the surface and interior of the membrane, and other water-insoluble.hydrophobic tails face each other

it also contains cholesterol molecules which are embedded in the animal cell membranes only . they help make the membrane ( along with phospholipids) impermeable to water soluble substances. cholesterol also stabilizes the membrane.
other integral proteins serve as channel proteins and selectively transports ions for the cell through facilitated diffusion.
gobular proteins are peripheral ( they are associated with the surface of the cell) may be enzymes or glycoproteins that helps with identification and recognition.

Answer 2

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