Briefly describe the structure of a eukaryotic plasma membrane, identifying at least two component macromolecules and describing what their basic function is within the membrane.
The plasma membrane is the boundary which separates the living cell from its nonliving surroundings. Being a thin semi membrane layer, it surrounds cytoplasm and the other components of the cell. This structure keeps the contents of a cell separate from the environment surrounding it (Shmoop Editorial Team,2008).
The eukaryotic plasma membrane is a phospholipid bilayer with proteins and cholesterol embedded in it. With this in mind, I would like to describe about proteins and cholesterol.
Proteins act as pumps, receptors, channels, enzymes or structural components.
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Cholesterol molecules are primarily affect the rigidity of the plasma membrane. At lower temperatures, when the membrane would like nothing more than to freeze in place, cholesterol helps the membrane loosen up. At higher temperatures, though, cholesterol raises the melting point of the membrane, preventing it from smooshing into a mushy paste (Shmoop Editorial Team, 2008).
Summarise the manner in which small molecules are permitted to pass through the membrane ensuring you explain the difference between passive, facilitated, active, and coupled transport by comparing and contrasting them.
The plasma membrane surrounding animal cells is where the exchange of substances inside and outside of cells takes place. That is to say, some substances can pass through a border, such as a cell membrane. The reason why some substances are able to allowed to pass through is due to act of the proteins.
Some of the proteins that are stuck in the plasma membrane help to form openings (channels) in the membrane. Through these channels, some substances such as hormones or ions are allowed to pass through. Transporting substances across the plasma membrane can require that the cell use some of its energy. If energy is used, the transport is called active. If molecules can pass through the plasma membrane without using energy, the molecules are using passive transport (How Cell Substances Transport through the Plasma Membrane, n.d.,