Animal Nutrition

Question 1

Balanced diet

Answer 1

A balanced diet contains all the essential nutrients (Ex: Carbohydrates, Proteins, and fats), in the correct amounts and proportions.

Question 2

how age, gender and activity affect the dietary needs of humans including during pregnancy and whilst breast-feeding

Answer 2

Amount of nutrients needed by people in different gender and age groups vary, it also depends on physical activity. Pregnant and breastfeeding women require more nutrients, as they must be able to feed their baby as well as themselves.

Question 3

Nutrients and their importance

Answer 3

Carbohydrates: (pasta, Rice, Potatoes)
-Used as a source of energy in respiration in cells.
Fats: (Cheese, Meat, Butter)
-Insulation, energy, waterproofing, structure and protection under delicate organs
Protein: (Meat, Fish, Eggs)
-Broken down into amino acids in digestion and absorbed in the blood and are used in cells to produce new proteins by Protein synthesis, where they are used as enzymes in reactions and for structure. Used for signaling hormones, carrying other molecules (haemoglobin which carries oxygen in the blood).
Vitamin C & D: (Citrus fruits and some vegetables) (Dairy products, fish oil)
-Used in synthesis of proteins that help make up the skin, ligaments and blood vessels. Also used to repair tissues. Vitamin D, helps uptake calcium during digestion, Factor in maintaining healthy bones.
Mineral salts (calcium and Iron): (dairy products and fish)
-Calcium needed for healthy bones and teeth, plays role in blood clotting. Iron (found in red meat and some green vegetables) is present in hemoglobin, plays important role in transporting oxygen around body in blood for cells to use in respiration.
Fibre (roughage): (Vegetables, Fruits and whole grains).
-Fibre not digested thus helps with constipation, as it moves food through stomach and intestine.
Water: 80% from drinks, 20% from food.
-water moves in blood via osmosis during digestion and into cells, acts as solvent so reactions can occur. helps maintain constant temperature in body, due to high specific heat capacity, and is a metabolite.

Question 4

Describe the effects of malnutrition in relation to starvation, constipation, coronary heart disease, obesity and scurvy

Answer 4

Lack of diet leads to malnutrition. Outcomes:

• Starvation: Caused by eating too little food, leads to weight loss, organ damage, muscle atrophy, then death.
• Constipation: Lack of fibre, leads to pain, stomach ache, inability to defecate.
• CHD: caused by build up of cholesterol in the artery, which limits blood flow to the heart, and causes heart attacks. Cholesterol is a result of too much saturated fat in the diet, coming from food high of fat, fatty meats.
• Obesity: Caused by eating too much food, leads to diabetes, high blood pressure, strokes, and heart disease.
• Scurvy: Caused by lack of vitamin C, leads to bleeding under gums, premature stopping of bone growth in children, leading to stunned growth, very dry hair and skin.

Question 5

causes and effects of vitamin D and iron deficiencies

Answer 5

Vitamin D
-Causes: Lack of vitamin D in diet
-Effects: Rickets, Bones become soft and deformed, common to younger children, causing stunned growth.
Iron
-Causes: Blood loss, lack of iron in diet.
-Effects: Anaemia, where there is not enough RBC, so tissues dont get enough oxygen delivered to them.

Question 6

Explain the causes and effects of protein-energy malnutrition, e.g. kwashiorkor and marasmus

Answer 6

-Kwashiorkor and Marasmus: Caused by protein-energy malnutrition, result of having a protein or calorie deficiency over a long period of time, Kwashiorkor, occurs due to severe protein deficiency, and carbohydrates- based diet, developed by older children. whereas marasmus is common with young children and babies.

Question 7

Ingestion

Answer 7

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

Question 8

Mechanical digestion

Answer 8

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

Question 9

Chemical digestion

Answer 9

the breakdown of large, insoluble molecules into small, soluble molecules

Question 10

Absorption

Answer 10

the movement of small food molecules and ions through the wall of the intestine into the blood

Question 11

Assimilation

Answer 11

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

Question 12

Egestion

Answer 12

the passing out of food that has not been digested or absorbed, as faeces, through the anus

Question 13

Diarrhoea

Answer 13

the loss of watery faeces

Question 14

treatment of diarrhoea

Answer 14

oral rehydration therapy: giving a drink containing water with a small amount of salt and sugar dissolved it.

Question 15

cholera

Answer 15

Is a disease caused by a bacterium. Although most bacteria are killed in acidic conditions of the stomach, some pass through the small intestine where they stick to the intestinal walls. Here the cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water into the gut, causing diarrhoea, dehydration and loss of salts from blood

Question 16

main regions of the alimentary canal and associated organs

Answer 16

• Mouth and salivary glands: Food mechanically digested in mouth by teeth, salivary glands secrete saliva that contains carbohydrates enzyme, which begin chemical digestion in stomach
• Oesophagus: Allows food to pass from mouth to stomach by peristalsis.
• Stomach: Protease enzyme breaks down protein in chemical digestion, food is also churned to break it even more in mechanical digestion. HCL acid present to maintain an optimum pH for enzyme action and kills bacteria in extreme acidic conditions. Which denatures enzymes within them.
• Small intestine: Consists of duodenum and ileum, in duodenum, acidity of stomach is neutralized and protease, lipase, and amylase enzyme are secreted to break down molecules. The ilium is final part of the small intestine, where products of digestion are absorbed into the blood.
• Pancreas: Secrete pancreatic juice into small intestine. It contains lipase, protease and amylase enzyme to break down food so it can be absorbed.
• Liver: Makes bile, which is secreted into small intestines. It neutralizes the acidic conditions from stomach (bile is alkaline) to provide suitable pH for enzymes to work at. Also emulsifies fat, increasing their surface area, so enzymes can digest them more quickly.
• Gall bladder: Bile made in liver, stored in gall bladder before being secreted into small intestine.
• Large intestine: Indigestible food passes through the large intestine, large intestine consist of colon, rectum, and anus. Remaining salts and water absorbed here (Most absorbed in small intestine).

Question 17

Functions of the regions of the alimentary canal, in relation to ingestion, digestion, absorption, assimilation and egestion of food

Answer 17

Once food is ingested, it undergoes chemical and mechanical digestion to break the food. Mechanical digestion food into smaller pieces without chemical change to the food molecules, occurs in mouth. Chemical digestion breakdown of large, insoluble molecules into small, soluble molecules, with the use of enzymes so that the products can be absorbed. Absorption which is the movement of small food molecules and ions through the wall of the intestine into the blood occurs, these molecules travel around the body where they are assimilated into cells and used in metabolic reactions. Food that is not absorbed or digested is egested as faeces.

Question 18

types of human teeth

Answer 18

Incisors: Chisel shaped for biting off food
Canines: Canines are similar to incisors
Premolars: Have wide surfaces for grinding food.
Molars: Like premolars, are used for grinding.
(2123): 2 incisors, 1 canine, 2 premolars, 3 molars
-Adults 32 permanent teeth
-Children have 20 teeth

Question 19

structure of human teeth

Answer 19

Enamel: Very hard, covers tooth & protects tissue inside
Dentine: Found underneath enamel, less hard than enamel thus decays more easily if enamel is worn away.
Pulp: Central part of the tooth, made up of soft tissue, which contains blood vessels and nerves.
Cement: Covers root of tooth and stabalises it.
gums: keep teeth in place and provide a barrier against bacteria.

Question 20

causes of dental decay

Answer 20

Dental decay occurs due to bacteria coating the teeth. when bacteria respire, using sugars from food, they produce acidic substance. It dissolves the enamel on the outer layer of the teeth and the inside of dentine, leading to tooth decay.

Question 21

proper care of teeth in terms of diet and regular brushing

Answer 21

To avoid tooth decay, the teeth should be regularly brushed to remove bacteria and sugary foods and drinks should be limited.

Question 22

significance of chemical digestion in the alimentary canal in producing small, soluble molecules that can be absorbed

Answer 22

Chemical digestion Is important, to allow food to be broken down into small molecules so that it can be absorbed and used in the body.

Question 23

functions of enzymes:

Answer 23

• Amylase breaks down starch to simpler sugars: it breaks down starch into maltose and then maltose into glucose, Maltase is a membrane-bound enzyme found in membranes of epithelial cells in the small intestine. Amylase found in small intestine and saliva
• Protease breaks down protein to amino acids: pepsin and trypsin are proteases. Pepsin work in the stomach, whereas trypsin in the small intestine. These enzymes have different optimum pH, since in the stomach conditions are very acidic (1.5), whereas in small intestine pH is 6-7. These enzymes will stop working in wrong pH as they will become denatured.
• Lipase breaks down fats to fatty acids and glycerol: it is secreted into small intestine.

Question 24

role of bile in neutralising the acidic mixture of food and gastric juices entering the duodenum from the stomach

Answer 24

• It provides the alkaline conditions needed in the small intestine, to provide a suitable pH for enzyme action

Question 25

role of bile in emulsifying fats

Answer 25

to increase the surface area for the chemical digestion of fat to fatty acids and glycerol by lipase

Question 26

small intestine

Answer 26

the region for the absorption of digested food

Question 27

significance of villi and microvilli in increasing the internal surface area of the small intestine

Answer 27

Villi and microvilli increase the internal surface area of the small intestine, to increase the amount of absorbed nutrients.

Question 28

the Function and structure of a villus

Answer 28

• The function of a villi is the absorption of digested nutrients into the blood.
• made up of epithelia cells, have microvilli, blood capillaries, have lacteals

Question 29

roles of capillaries and lacteals in villi

Answer 29

Capillaries:
-Transports glucose and amino acids away from the small intestine in the blood.
Lacteals: Absorb fatty acids (lipids)
- Transports fatty acids and glycerol away from the small intestine in the lymph.

Question 30

Water absorption

Answer 30

Water is absorbed in both the small intestine and the colon, but that most absorption of water happens in the small intestine