Plasma Membrane

Front

What is the plasma membrane?

Back

The plasma membrane is a biological membrane that separates and protects the interior of all cells from the external environment. It is composed of a phospholipid bilayer with embedded proteins.

Front

What is the function of channel proteins in the plasma membrane?

Back

Channel proteins facilitate the transport of specific molecules across the plasma membrane by forming pores that allow substances to pass through.

Front

What is the function of carrier proteins in the plasma membrane?

Back

Carrier proteins bind to specific molecules and change shape to shuttle them across the plasma membrane.

Front

What is the phospholipid bilayer?

Back

The phospholipid bilayer is a double layer of phospholipids that makes up the plasma membrane, with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward.

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What role do cholesterol molecules play in the plasma membrane?

Back

Cholesterol molecules help to stabilize the fluidity of the plasma membrane, making it less permeable to very small water-soluble molecules that might otherwise pass freely through.

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What is a concentration gradient?

Back

A concentration gradient is the difference in the concentration of a substance across a space, which drives the movement of molecules from areas of higher concentration to areas of lower concentration.

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What is selective permeability?

Back

Selective permeability is a property of the plasma membrane that allows certain molecules to pass through while blocking others, thus maintaining the internal environment of the cell.

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What are integral proteins?

Back

Integral proteins are proteins that are embedded within the phospholipid bilayer and can span the entire membrane, playing key roles in transport and communication.

Front

What are peripheral proteins?

Back

Peripheral proteins are proteins that are attached to the exterior or interior surfaces of the plasma membrane and are not embedded within the lipid bilayer.

Front

What is the fluid mosaic model?

Back

The fluid mosaic model describes the structure of the plasma membrane as a mosaic of various components (lipids, proteins, carbohydrates) that are able to move fluidly within the layer.