N5 1.2 Transport Across Membranes Flashcards

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Components of cell membranes

Back

Proteins and Phospholipids

Front

Membrane proteins

Back

One type of molecule that makes up the cell membrane.

Involved in active transport where they require energy to move molecules and ions against the concentration gradient.

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Selectively permeable

Back

cell membrane controls the size of molecules that can pass through

Front

Concentration Gradient

Back

The difference in concentration between two solutions or cells

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Passive transport

Back

The movement of molecules from a region of higher concentration to a region of lower concentration.

Requires NO energy.

e.g. Diffusion & Osmosis

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Diffusion

Back

The movement of molecules down a concentration gradient from an area of higher concentration to an area of lower concentration.

Example of Passive transport as it requires no energy. 

Front

Examples of substances that enter animal cells by diffusion are

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Glucose and Oxygen

(which are required for respiration)

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Example of a substance that leaves animal cells by diffusion is

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Carbon dioxide (waste product of respiration)

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Osmosis

Back

The movement of water molecules from a higher to a lower water concentration through a selectively permeable membrane.

Example of Passive transport as it requires no energy. 

Front

Animal cells bursting

Back

An animal cell placed in a solution with a higher water concentration compared to its cytoplasm (such as pure water) will gain water by osmosis, swell up and burst.