Cell Membrane & Transport Flashcard

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What is the cell membrane?

Back

The cell membrane is a biological barrier that separates the interior of a cell from its external environment, composed mainly of a phospholipid bilayer with embedded proteins.

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What is passive transport?

Back

Passive transport is the movement of molecules across the cell membrane without the use of energy, typically moving from an area of high concentration to an area of low concentration.

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What is active transport?

Back

Active transport is the movement of molecules across the cell membrane against their concentration gradient, requiring energy, often in the form of ATP.

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What is diffusion?

Back

Diffusion is the process by which small molecules move from an area of high concentration to an area of low concentration until equilibrium is reached.

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What is facilitated diffusion?

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Facilitated diffusion is a type of passive transport that uses protein channels to help larger or polar molecules cross the cell membrane.

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What is endocytosis?

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Endocytosis is the process by which cells engulf large molecules or particles by wrapping them in a portion of the cell membrane, forming a vesicle.

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What is exocytosis?

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Exocytosis is the process by which cells expel materials by vesicles fusing with the cell membrane, releasing their contents outside the cell.

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What role do protein pumps play in active transport?

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Protein pumps are integral membrane proteins that use energy to transport ions or molecules against their concentration gradient.

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What is the function of cholesterol in the cell membrane?

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Cholesterol helps to stabilize the cell membrane and regulate its fluidity, making it less permeable to very small water-soluble molecules.

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What is osmosis?

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Osmosis is the diffusion of water molecules across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.