Chapter 7: human Nutrition

Question 1

What is a balanced diet?

Answer 1

A diet that contains all essential nutrients (carbohydrates, fats, proteins, vitamins, mineral salts, fibre and water) in the correct amounts for growth, repair and as an energy source.

Question 2

Importance of carbohydrate and source

Answer 2

Used as a source of energy in respiration in cells.
Pasta, rice and potatoes

Question 3

Importance of protein and source

Answer 3

Fish, meat and lentils

to build and repair muscles and bones and to make hormones and enzymes.

Question 4

Importance of fat and source

Answer 4

insulation, storing energy, waterproofing, structure and protection around delicate organs

full-fat milk, cheese, butter, cream

Question 5

Importance of vitamin C and D and source

Answer 5

Vitamin D is found in dairy products, eggs and fish oil. It helps the uptake of calcium during digestion and is also a factor in maintaining healthy bones.
Vitamins C citric fruits. protect cells and maintain healthy connective tissue, blood vessels, bones and cartilage.

Question 6

Importance of calcium and iron and source

Answer 6

Calcium is needed for healthy bones and teeth and is found in dairy products and fish.

Iron is required to make the protein haemoglobin found in red blood cells. Iron is found in red meat and some green vegetables.

Question 7

Importance of fiber and source

Answer 7

fibre is important for health as it aids digestion, helps control blood sugar levels, and reduces cholesterol levels.

Found in vegetables, fruit and whole grains

Question 8

Importance of water

Answer 8

Water is important for all living organisms as many substances are able to dissolve in it (it is a solvent)

Question 9

Vitamin D deficiency

Answer 9

Cause rickets

Question 10

Vitamin c deficiency

Answer 10

Scurvy

Question 11

main organs of the digestive system

Answer 11

alimentary canal: mouth, oesophagus, stomach, small intestine (duodenum and ileum) and large intestine (colon, rectum, anus)
associated organs: salivary glands, pancreas, liver and gall bladder

Question 12

Ingestion

Answer 12

the taking of substances, e.g. food and drink, into the body

Question 13

digestion

Answer 13

the breakdown of food

Question 14

absorption

Answer 14

the movement of nutrients from the intestines into the blood

Question 15

assimilation

Answer 15

uptake and use of nutrients by cells

Question 16

egestion

Answer 16

the removal of undigested food from the body as faeces

Question 17

Describe physical digestion

Answer 17

the breakdown of food into smaller pieces without chemical change to the food molecules

Question 18

What does physical digestion do?

Answer 18

physical digestion increases the surface area of food for the action of enzymes in chemical digestion

Question 19

Types of human teeth

Answer 19

incisors, canines, premolars and molars

Question 20

structure of human teeth

Answer 20

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enamel, dentine, pulp, nerves, blood vessels and cement, and understand that teeth are embedded in bone and the gums

Question 21

Describe the function of the stomach in physical digestion

Answer 21

The stomach’s muscular walls contract to mechanically break down food

Question 22

Role of bile

Answer 22

Bile emulsifies fatty acids and lipids, breaking large chains into smaller droplets. This increases the surface area for enzymes (lipase) to act on, therefore increasing the rate of digestion/the breakdown of fats.

Question 23

Describe chemical digestion

Answer 23

the break down of large insoluble molecules into small soluble molecules

Question 24

the role of chemical digestion

Answer 24

producing small soluble molecules that can be absorbed

Question 25

Describe the digestion of starch in the digestive system:

Answer 25

(a) amylase breaks down starch to maltose
(b) maltase breaks down maltose to glucose on the membranes of the epithelium lining the small intestine

Question 26

Break down of protein and lipids

Answer 26

proteases break down protein to amino acids
lipase breaks down fats and oils to fatty acids and glycerol

Question 27

Describe the digestion of protein by proteases in the digestive system:

Answer 27

(a) pepsin breaks down protein in the acidic conditions of the stomach
(b) trypsin breaks down protein in the alkaline conditions of the small intestine

Question 28

Where is amylase secreted and act?

Answer 28

Secreted
the salivary glands and the pancreas
Act
Small intestine and mouth

Question 29

Where are protease and lipase secreted and act?

Answer 29

Secreted
Protease- stomach, pancreas and small intestine
Lipase- pancreas
Act
Protease- stomach and duodenum
Lipase- duodenum ( first part of small intestine)

Question 30

Function of Hydrochloric Acid in gastric juice

Answer 30

killing harmful microorganisms in food and providing an acidic pH for optimum enzyme activity

Question 31

What is bile?

Answer 31

is an alkaline mixture that neutralises the acidic mixture of food and gastric juices entering the duodenum from the stomach, to provide a suitable pH for enzyme action

Question 32

Where are nutrients absorbed?

Answer 32

the small intestine is the region where nutrients are absorbed

Question 33

Importance of villi and microvilli

Answer 33

increasing the internal surface area of the small intestine so they can absorb the maximum amount of nutrients.

Question 34

Describe the structure of a villus

Answer 34

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Question 35

Describe the structure of a villus

Answer 35

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Question 36

Describe the roles of capillaries and lacteals in villi

Answer 36

The capillaries within the villi absorb most nutrients, while the lacteals, a part of the lymphatic system, absorb fatty acids and glycerol from dietary fats.

Question 37

Where is water absorbed?

Answer 37

most water is absorbed from the small intestine but that some is also absorbed from the colon