N5 1.2 Transport Across Membranes

What are the components of cell membranes?

• Protein and carbohydrate molecules

• Protein and phospholipid molecules

• Phospholipid and carbohydrate molecules

• DNA and proteins

Label the components of the cell membrane.

a

b

Protein

Phospholipid

What does it mean when cell membranes are described as 'selectively permeable'?

• They allow all substances to pass through freely

• They prevent any substances from passing through

• They control what substances pass through the membrane

What is a concentration gradient?

• The process by which solutions are mixed

• The difference in concentration between two solutions

• The temperature difference between two solutions

How does the difference in concentration between two solutions affect the rate of diffusion?

• The smaller the difference, the faster the diffusion

• The bigger the difference, the slower the diffusion

• The bigger the difference, the faster the diffusion

• The difference does not affect the rate of diffusion

Which of the following are examples of passive transport?

• Active Transport

• Osmosis

• Diffusion

(a)   is NOT a method of molecule movement through membranes.

• Osmosis
• Diffusion
• Active Transport
• Photosynthesis

What is passive transport?

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

• The movement of molecules from a region of higher concentration to a region of lower concentration without using energy.

• The active pumping of molecules against a concentration gradient using ATP.

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

Passive transport requires energy to occur: (a)   .

• Yes, it requires ATP.
• No, it does not require any energy.

What is diffusion?

• The movement of molecules from an area of lower concentration to an area of higher concentration.

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

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