The Digestive System

Question 1

What is intracellular digestion?

Answer 1

Digestion that takes place inside cells
eg during phagocytosis

Question 2

What is extracellular digestion?

Answer 2

Digestion that takes place outside cells
eg bacteria, fungi and in the digestive tract

Question 3

Label the diagram:

Answer 3

Question 4

What do salivary glands do?

Answer 4

Found in mouth
Secrete saliva containing enzyme amylase which hydrolysed starch into maltose

Question 5

What is the path food takes for digestion?

Answer 5

1. Mouth (buccal cavity)
2. Oesophagus (tube taht carries food from the mouth to stomach)
3. Stomach (muscular sac)
4. Muscle in stomach wall contracts and churns the contents known as a chyme
5. Food passes through ileum
6. Undigested food passes into large intestine where water is absorbed
7. Faeces stored in reaction and removed via anus in the process of egestion

Question 6

Why do the cells lining the stomach produce hydrochloric acid?

Answer 6

Acid provides optimum pH for protease enzymes in the stomach to hydrolyse proteins

Question 7

What happens in small intestine (ileum) and how is it adapted for food absorption?

Answer 7

• Pancreatic secretion containing bile and pancreatic enzymes hydrolyse carbohydrates, lipids and proteins (carbohydrases, lipases and proteases)
• inner walls of ileum are folded into villi which have a large surface area which is further increased by millions of tiny projections called microvilli. These are adapted for absorbing the products of digestion into the bloodstream

Question 8

What is physical digestion?

Answer 8

• This is when large food particles are broken down the the action of the teeth.
• Increases surface area for chemical digestion
• Churning of muscles in stomach is also physical digestion

Question 9

What is chemical digestion?

Answer 9

Specific enzymes carrying out hydrolysis reaction using water to break chemical bonds