Transport across cell membranes Flashcards

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1
Q

What are membranes made of?

A

Phosopholipids and proteins.

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2
Q

What is diffusion?

A

The movement of substances from a high concentration to a low concentration down a concentration gradient.

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3
Q

What kind of process is diffusion (energy)?

A

A passive process which requires no energy.

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4
Q

Why is diffusion important to living cells?

A

It is the way that substances are moved from cell to cell and between cells and their surroundings.

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5
Q

What is: The movement of substances from a high concentration to a low concentration down a concentration gradient?

A

Diffusion.

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6
Q

What is: OSMOSIS?

A

The movement of water from a high water concentration to a low water concentration through a selectively permeable membrane.

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7
Q

What happens in an animal cell during osmosis if there is a higher water concentration (hypotonic solution)?

A

Water enters by osmosis and the cell burts.

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8
Q

What happens in an animal cell during osmosis if there is a lower water concentration (hypertonic solution)?

A

The cell shrinks and wrinkles. Water is lost by osmosis.

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9
Q

Why does osmosis effect plant cells differently?

A

Because of the presence of a cell wall.

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10
Q

What happens in an plant cell during osmosis if there is a higher water concentration (hypotonic solution)?

A

Water enters by osmosis. The vacuole swells and the cell is turgid.

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11
Q

What happens in an plant cell during osmosis if there is a lower water concentration (hypertonic solution)?

A

Lose water by osmosis. The vacuole shrinks and the membrane pulls away from the cell wall. The cell is plasmolysed.

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12
Q

What is: The movement of water from a high water concentration to a low water concentration through a selectively permeable membrane?

A

Osmosis

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13
Q

Explain what kind of cell this happens to: Water enters by osmosis and the cell burts.

A

In an animal cell if there is a higher water concentration (hypotonic solution).

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14
Q

Explain what kind of cell this happens to: The cell shrinks and wrinkles. Water is lost by osmosis.

A

In an animal cell if there is a lower water concentration (hypertonic solution)

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15
Q

Explain what kind of cell this happens to: Water enters by osmosis. The vacuole swells and the cell is turgid.

A

In an plant cell if there is a higher water concentration (hypotonic solution)

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16
Q

Explain what kind of cell this happens to: Lose water by osmosis. The vacuole shrinks and the membrane pulls away from the cell wall. The cell is plasmolysed.

A

In an plant cell if there is a lower water concentration (hypertonic solution)

17
Q

What is: ACTIVE TRANSPORT

A

The movement of molecules against a concentration gradient from a region of low concentration to a region of high concentration.

18
Q

What does active transport need to make it happen?

A

ATP (energy)

19
Q

What do proteins do in the membrane?

A

In the membrane proteins act as carriers and transport the molecules (and ions) across the membrane.

20
Q

What is an example of active transport?

A

In nerve cells, sodium is pumped out and potassium is pumped in.

21
Q

What is: The movement of molecules against a concentration gradient from a region of low concentration to a region of high concentration?

A

Active Transport

22
Q

In the membrane what act as carriers and transport the molecules (and ions) across the membrane?

A

Proteins

23
Q

What is this an example of: In nerve cells, sodium is pumped out and potassium is pumped in?

A

Active Transport