Animal Nutrition I

Question 1

What is the definition of nutrition?

Answer 1

Nutrition is the process by which organisms obtain food [1] and energy [2] for growth [3], repair [4], and maintenance of body [5].

Question 2

What is the function of the digestive system?

Answer 2

To break down large and complex food substances into smaller and simple food substances

Question 3

What is the difference between physical digestion and chemical digestion?

Answer 3

1) The identities of food substance remains unchanged in physical digestion. However, in chemical digestion, the identities of the food substance change, and new products are formed.

2) Physical digestion often increases the surface area to volume ratio. Chemical digestion is to allow food substances to enter the bloodstream through intestinal walls.

Question 4

Is emulsification physical digestion?

Answer 4

yes. As there are no new products formed during the process.

Question 5

What is the function of the mucus along the gut?

Answer 5

1) The mucus protects the stomach wall from being damaged by HCL

2) Prevents digestion by pepsin since the stomach wall is made of protein.

3) Provides lubrication as food is churned in stomach

Question 6

What is ingestion?

Answer 6

Ingestion is food taken into the body.

Question 7

What is digestion?

Answer 7

Digestion is large food substances broken down into small soluble substances.

Question 8

What is absorption?

Answer 8

It is the process at which small, soluble substances is being absorbed into the cell

Question 9

What is assimilation?

Answer 9

Assimilation is the process at which substances are used to provide new energy/ make new protoplasm.

Question 10

What is egestion?

Answer 10

It is undigested food removed from the body as waste product.

Question 11

Where does ingestion occur?

Answer 11

Mouth

Question 12

What is the function of the salivary gland and tongue in mouth?

Answer 12

Salivary gland - produce saliva
tongue - aids to mix food with saliva

Question 13

What does saliva consist?

Answer 13

salivary amylase, mucus and water

Question 14

Why does salivary amylase function effectively in the mouth?

Answer 14

This is due to saliva, which provides a neutral environment for it to function properly.

Question 15

Why must food be chewed?

Answer 15

By doing so, food is cut and grind into smaller pieces. This increases surface area to volume ratio and allows enzymes to digest them faster.

Question 16

What is starch digested into by salivary amylase?

Answer 16

Maltose

Question 17

What is peristalsis?

Answer 17

It is the rhythmic- wave- like contraction of muscles of the wall.

Question 18

How is food being pushed down into the stomach in the oesophagus?

Answer 18

The 2 muscles (circular and longitudinal) work antagonistically to bring about the movement of food along the oesophagus via peristalsis, pushing the food along the canal down the stomach with gravity.

Question 19

Is there digestion of carbohydrates in the stomach? Explain.

Answer 19

No.
1) Salivary amylase are denatured in the stomach due to it’s acidic environment.

2) The stomach does not produce any suitable form of amylase for digestion of starch.

3) May cause hydrolysis of salivary amylase protein.

Question 20

Where does protein digestion occur?

Answer 20

Stomach and small intestine.

Question 21

What is the function of the strong muscular walls in the stomach?

Answer 21

The stomach muscular wall contract and relax, causing the peristaltic action (churn) to bring food into close contact with gastric juice.

Question 22

Why does the mucous lining in the stomach have numerous pits?

Answer 22

It is to bear mucous secreting epithelial cells which secretes mucous.

Question 23

what do gastric juice contain?

Answer 23

Hydrochloric acid.
Rennin and Pepsin (enzymes)

Question 24

What is the function of hydrochloric acid in the stomach?

Answer 24

1) HCl converts inactive prorennin and pepsinogen into active pepsin and rennin.

2) Provides acidic environment in stomach such that protease can function efficiently in this optimum condition.

3) kill germs and parasites

4) stop the action of salivary amylase

Question 25

Describe the physical digestion in the stomach.

Answer 25

The churning action [1] by the muscular wall of the stomach causes food to break further into smaller pieces. It also helps food mix with gastric juice which increases surface area to volume ratio[1] to act more efficiently.

Question 26

what does pepsin convert proteins into in the stomach?

Answer 26

polypeptides

Question 27

What does rennin convert caseinogen(soluble) into in the stomach?

Answer 27

casein (insoluble)

Question 28

Why is milk proteins in the form of soluble caseinogen not beneficial?

Answer 28

When milk proteins are in the form of caseinogen, they would pass through the stomach to the small intestine very quickly [1]. This prevents pepsin digestion to take place [1]. Thus, rennin changes caseinogen into an insoluble form to give pepsin sufficient time to digest it. [1]

Question 29

Why is the nature of juices from intestinal glands, pancreatic juice and gall bladder alkaline?

Answer 29

1) Being alkaline, it provides suitable alkaline medium for optimum action of all the enzymes.

2) It neutralises acidic chyme

Question 30

Why is the small intestine 7m long?

Answer 30

This is to allow for maximum absorption [1] and allow time for digestion [1].

Question 31

Where does digestion occur in the small intestine?

Answer 31

Duodenum

Question 32

Where does emulsification occur?

Answer 32

small intestine.

Question 33

Where is bile produced and stored at?

Answer 33

Bile is produced by the liver, and stored at gall bladder

Question 34

Is bile an enzyme? explain.

Answer 34

Bile is not an enzyme as it breaks up fat molecules into fat globules.

Question 35

What is the function of emulsification?

Answer 35

It increases surface area to volume ratio of the fat molecules so that they can be digested by lipase faster, increasing efficiency.

Question 36

Which organ secretes pancreatic juice into duodenum?

Answer 36

pancreas

Question 37

How is pancreatic juice transported to the small intestine?

Answer 37

via the pancreatic duct

Question 38

What does pancreatic juice contain?

Answer 38

Pancreatic amylase, lipase and trypsinogen.

Question 39

What are the end products of carbohydrate digestion?

Answer 39

Simple sugar [glucose, fructose and galactose]

Question 40

What are the 6 enzymes that intestinal juice contain?

Answer 40

Maltase, surcease, lactase, lipase, erepsin and enterokinase.

Question 41

What are the 3 organs associated with the alimentary gut?

Answer 41

pancreas, liver and gall bladder.

Question 42

Name the organs that are responsible for the secretion and production of bile?

Answer 42

Liver - produce bile
Bile duct- transport bile to duodenum
Gall bladder- stores bile