Flashcards- Ch 7 Passive Transport

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Selectively permeable

Back

Property of biological membranes which allows some substances to pass more easily than others.

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Function of channel proteins

Back

Move molecules across the membrane that the membrane is impermeable to; May provide a hydrophilic tunnel through the membrane; May physically bind to a substance to move it across

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Specificity of channel proteins

Back

Channel proteins are specific for the substance they move.

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Movement across the cell membrane can be passive

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Passive transport means the cell does not have to expend energy; molecules are moving down their concentration gradient (from high to low concentration)

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Movement across the cell membrane can be active

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Active transport is an energy-requiring process where a transport protein pumps a molecule across a membrane against its concentration gradient.

Front

Diagram showing passive and active transport across a cell membrane

Back

The diagram illustrates passive transport as moving with the concentration gradient and active transport as moving against it, requiring energy.

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Passive Transport: Simple Diffusion

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The net movement of a substance down a concentration gradient, resulting from random molecular movement. It continues until equilibrium is reached and is not selective. Example: O₂ and CO₂ move through phospholipids based on size and nonpolar vs. polar properties.

Front

discuss the image as an example of diffusion

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Illustrates the process of simple diffusion where molecules move across a semi-permeable membrane, from high to low concentration until equilibrium is reached. In this diagram the net movement would be down.

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Facilitated diffusion

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Involves the diffusion of solutes across a membrane (from high to low concentration) with the help of transport proteins. No energy is needed.

Front

True or False: Channels in facilitated diffusion are selective to what they transport.

Back

TRUE