Transport across cell membranes

What does the cell membrane consist of?

phospholipids and proteins

What is the cell membrane?

It is selectively permeable

What is passive transport?

Passive transport is the movement of molecules of a substance down a concentration gradient and does not require additional energy.

Examples of passive transport?

diffusion and osmosis

Different ________________ of substances exist between _______ and their ______________

- concentrations
- cells
- environment

What is diffusion?

the movement of molecules down a concentration gradient from a higher to a lower concentration.

If oxygen is the substance required by the cell. What is the waste product?

Carbon dioxide

If carbon dioxide is the substance required by the cell. What is the waste product?

Oxygen

If glucose is the substance required by the cell. What is the waste product?

Urea

What is osmosis?

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

When placed in a solution animals cells can either?

Burst or Shrink

When placed in a solution plant cells can either?

Become turgid or plasmolysed

If an animal cell is placed in a solution with a higher water concentration compared to their contents, What will happen?

They will gain water by osmosis, swell up and burst.

If an animal cell is placed in a solution with a lower water concentration compared to their contents, What will happen?

They will lose water by osmosis and shrink.

If a plant cell is placed in a solution with a high water concentration compared to their contents, What will happen?

They will gain water by osmosis and swell up until their cytoplasm and cell membrane are pushing against their cell wall. They are said to be turgid.

If a plant cell is placed in a solution with a low water concentration compared to their contents, What will happen?

They will lose water by osmosis. Their cell membranes will peel away from their cell walls and they are said to be plasmolysed.

What is active transport?

active transport is a type of transport that requires energy for
membrane proteins to move molecules and ions against the concentration gradient.