2 Transport and Exchange in Animals

Question 1

Diffusion

Answer 1

The net movement of particles from an area of high concentration to an area of low concentration.

Question 2

What affects diffusion? (4)

Answer 2

• Distance - further distance, slower rate fo diffusion
• Concentration - higher concentration, faster rate of diffusion
• Temperature - higher temperature, faster rate of diffusion
• Surface area - larger surface area, faster rate of diffusion

Question 3

Osmosis

Answer 3

The movement of 𝘄𝗮𝘁𝗲𝗿 molecules from an area of high concentration to an area of low concentration through a partially permeable membrane.

Question 4

Active Transport (5)

Answer 4

The movement of substances against a concentration gradient, from an area of 𝗹𝗼𝘄 concentration to an area of 𝗵𝗶𝗴𝗵 concentration through a semi-permeable membrane. The process requires energy from respiration.

Question 5

What is special about cells that carry out active transport?

Answer 5

The cells contain large numbers of mitochondria to do respiration.

Question 6

Enzymes

Answer 6

Proteins that act as biological catalysts, which catalyse (speed up) chemical reactions in cells without being used up themselves.

Question 7

Lock and Key Theory

Answer 7

• The chemical which reacts is the substrate (key)
• Substrate fits into enzyme’s active site (lock)
• Theory is an example of how models are used in science to explain observations

Question 8

Denatured

Answer 8

• Caused by high temperatures and extremes of pH
• Causes the enzyme to change shape
• Enzyme doesn’t work because the substrate can’t fit into active site

Question 9

Digestive Enzymes:
• Protease
• Lipase
• Carbohydrase

Answer 9

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• Produced in pancreas, activated in small intestine
• Digests proteins

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• Produced in pancreas
• Digests lipids (fats and oils)

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• Produced in