6 Animal nutrition

Question 1

Define a balanced diet

Answer 1

A diet that includes all the nutrients our cells and tissues use.

Question 2

What is included in a balanced diet

Answer 2

Protein - broken down to make amino acids. These are used to form other proteins needed by cells.
Carbohydrates - broken down to simple sugars for use in respiration.
Fats - Helps maintain body temperature. Also a store of energy supply molecules for respiration.
Vitamins and minerals - needed in small amounts for correct functioning of body.
Fibre - made up of cell wall of plants. Sources - leafy vegetables, and unrefined grains.
Important in preventing constipation.
Water - necessary for all life processes.

Question 3

Role of vitamin C

Answer 3

For healthy skin, teeth, gums and lining of blood vessels.
Food source - citrus fruits, green vegetables, potatoes.
Deficiency disease - scurvy: bleeding gums, wounds not healing properly.

Question 4

Role of vitamin D

Answer 4

For strong bones and teeth.
Food source - fish, egg, liver, cheese, and milk.
Deficiency disease - rickets: softening of bone.

Question 5

Role of calcium

Answer 5

Needed for strong teeth and bones, involved in clotting of blood.
Food source - milk and eggs.
Deficiency disease - rickets: softening of bone.

Question 6

Role of iron

Answer 6

Needed to make haemoglobin in red blood cells.
Food source - red meats, liver and kidneys, leafy green vegetables.
Deficiency disease - anaemia: reduction in number of red blood cells, makes you tired and short of breath.

Question 7

Deficiency disease for protein

Answer 7

Kwashiorkor. Causes: children were breast-fed and then weaned. Symptoms include: swelling of feet and abdomen, wasting muscles, thinning hair and loss of teeth.

Question 8

Deficiency disease of all-energy containing foods

Answer 8

Marasmus. Short for age, very low body fat and muscle. Can be fatal due to dehydration, leading to heart problems and infections.

Question 9

Define Ingestion

Answer 9

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

Question 10

Define Digestion

Answer 10

The breakdown of large, insoluble food molecules into small, water soluble molecules using mechanical and chemical processes.

Question 11

Define Absorption

Answer 11

Movement of digested food
molecules through the wall of the intestine into the blood.

Question 12

Define Assimilation

Answer 12

The movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.

Question 13

Define Egestion

Answer 13

Passing out of food that has not been digested, as faeces, through the anus.

Question 14

Function of Mouth

Answer 14

Teeth and tongue break down food into smaller pieces.

Question 15

Function of Salivary glands

Answer 15

Produces liquid saliva, moistens food so it can be easily swallowed and contains enzyme amylase to begin breakdown of starch.

Question 16

Function of Oesophagus

Answer 16

Each lump of swallowed and chewed food, called a bolus, is moved from mouth to stomach via the oesophagus, by waves of, muscle called peristalsis.

Question 17

Function of Stomach

Answer 17

Acid and protease enzymes are secreted to start protein digestion; movements of the muscular wall churn up food into a liquid.

Question 18

Function of Liver

Answer 18

Cells in the liver make bile; amino acids not used for making proteins are broken down to form urea, which passes to the kidneys for excretion; excess glucose is removed from the blood and stored as glycogen in liver cells.

Question 19

Function of Gall bladder

Answer 19

Stores bile from the liver; the bile is passed along the bile duct into the small intestine, where it neutralises the stomach acid in the chyme.

Question 20

Function of Pancreas

Answer 20

Secretes digestive enzymes in an alkaline fluid into the small intestine.

Question 21

Function of Small intestine

Answer 21

Secretions from gallbladder and pancreas enter the first part of the small intestine to complete the process of digestion; digested food molecules and water are absorbed in the second part of the small intestine.

Question 22

Function of the Large intestine

Answer 22

Water is absorbed from the remaining material.

Question 23

Function of the Anus

Answer 23

Faeces are egested through a sphincter.

Question 24

What are the two types of digestion?

Answer 24

Mechanical digestion: occurs mainly in the mouth, food is broken down physically into smaller pieces without chemical change.
Chemical digestion: breakdown of large insoluble molecules into smaller molecules using chemicals such as enzymes.

Question 25

Location and function of Incisors

Answer 25

At front of mouth, chisel-shaped, for biting off food (particularly good with plant material).

Question 26

Location and function of Canines

Answer 26

Four of them, pointed, pierce and hold food, particularly meat, so that it can be chewed.

Question 27

Location and function of Premolars

Answer 27

Cutting off of tough foods, such as meat, and grinding of plant material on small grinding surface.

Question 28

Location and function of Molars

Answer 28

At back of mouth, have large grinding surfaces for chewing, particularly plant material.

Question 29

Describe Dental Decay

Answer 29

Enamel is very hard, but vulnerable to attack by acids (Naturally present in fruits and other foods, bacteria living in spaces between teeth, in crevices on tooth surface, and at edge of gums also makes acids. Bacteria grows on the food particles as it respires, forming plaque. This plaque allows easier growth of bacteria. Acids corrode tooth enamel and expose softer dentine underneath. This can cause pain when the nerves in the pulp cavity are affected by acid, heat or cold. Links between tooth and its socket can weaken, causing it to fall off.

Question 30

What are some methods of Tooth care

Answer 30

Brushing teeth: Toothpaste is alkaline so neutralises acids, contains antibacterial substances, usually contains mild abrasive that helps remove plaque, may contain fluoride, helps strengthen enamel and reduce acidic damage.
Flossing.
Reducing amount of sugary food eaten.

Question 31

Explain the role of Bile in digestion

Answer 31

Bile is a substance produced by cells in liver. Stored in gallbladder until needed and then passed along bile duct into small intestine. Bile is important in digestion of fats. Fats do not mix well with aqueous mixtures so remain as large droplets. Bile emulsifies fats, breaking them up into smaller droplets so that the surface area increases and rate of digestion is much faster.

Question 32

What are the Digestive enzymes

Answer 32

Group of enzymes that are produced in the cells lining parts of the digestive system and are secreted into the alimentary canal to mix with food.

• Carbohydrases that break down carbohydrates (E.g. Amylase).
• Proteases.
• Lipases.

Question 33

Where Amylase is produced, its substrate and its final product

Answer 33

Produced in salivary glands and pancreas. Its substrate is starch and the final product is glucose.

Question 34

Where Protease is produced, its substrate and its final product

Answer 34

Produced in stomach wall and pancreas. Its substrates are proteins and the final products are amino acids.

Question 35

Where Lipase is produced, its substrate and its final product

Answer 35

Fatty acids and Glycerol.

Question 36

Role of Hydrochloric acid in digestion.

Answer 36

Special cells in the lining of stomach secrete hydrochloric acid into stomach to create right acid conditions for enzymes. Also helps kill microorganisms taken in with the food. This is because low pH denatures enzymes so they cannot function properly. In small intestine, the enzymes from pancreas work best in slightly alkaline conditions. Bile is used to neutralise the acid entering duodenum and make digesting food slightly alkaline.