Chapter 3 - Organisation and the Digestive System

Question 1

Define the word tissue.

Answer 1

• A group of cells with similar structure and function working together.

Question 2

Define organ.

Answer 2

• Collection of tissues performing specific functions.

Question 3

Give 2-3 examples of organ systems.

Answer 3

• Respiratory system
• Digestive system
• Nervous system

Question 4

What is the digestive system?

Answer 4

• An organ system where several organs work together to digest/absorb food.

Question 5

Where is food mainly digested?

Answer 5

• Stomach and small intestine

Question 6

Which organ produces bile?

Answer 6

• The liver produces bile

Question 7

Explain the structure and function of carbohydrates.

Answer 7

• Carbohydrates are simple sugars
• Contains glucose and sucrose
• Provides long-term energy

Question 8

Explain the structure and function of lipids.

Answer 8

• Made from fatty acids and glycerol
• Important energy source

Question 9

Explain the structure and function of proteins.

Answer 9

• Made from a chain of amino acids.
• Builds/repairs cell/tissues

Question 10

State which colour the iodine test for starch and the Benedict’s test for sugars turn when both are present.

Answer 10

Iodine test - Yellow-red solution turns Blue-Black in presence of starch.
Benedict’s test - Blue solution turns Brick-Red on heating.

Question 11

What colour does blue Biuret reagent turn in the presence of protein?

Answer 11

• Purple

Question 12

State which test is used to test for lipids and describe the gas produced.

Answer 12

• Ethanol test
• Gives a cloudy white layer in presence of lipids

Question 13

What is the role of a catalyst?

Answer 13

• To increase the rate of reaction without chemical change.

Question 14

Define metabolism.

Answer 14

• The sum of all reactions in a cell/body

Question 15

What are enzymes and active sites?

Answer 15

• An enzyme is a biological catalyst.
• An active site is where the substrate binds to.

Question 16

Explain the lock and key theory.

Answer 16

• Substrate fits into active site.
• Enzyme and substrate bind.
• Rapid reaction takes place.
• Substrate splits into products and breaks away.

Question 17

What can effect enzyme activity?

Answer 17

• Temperature and pH

Question 18

How does pH affect enzyme action?

Answer 18

• It affects the shape of the active site so that the substrate no longer fits in. The chains holding the active site are lost.

Question 19

How does temperature affect enzyme action?

Answer 19

• Denatures the enzyme, changing the active sites’ shape.

Question 20

State which enzyme breaks down carbohydrates and where it is made.

Answer 20

• Amylase
• Made in salivary glands and pancreas

Question 21

State which enzyme breaks down protein and where it is produced.

Answer 21

• Protease
• Stomach, pancreas, small intestine

Question 22

Give the enzyme which breaks down fats and where it is produced.

Answer 22

• Lipase
• Pancreas and small intestine

Question 23

How does hydrochloric acid make digestion efficient?

Answer 23

• It gives the stomach a low pH for protease to work efficiently.