Human nutrition

Question 1

A balanced diet

Answer 1

contains the correct amount and proportion of carbohydrates, proteins, fats, vitamins, minerals, water, fiber (roughage).

Question 2

Principal and dietary sources are:

Answer 2

• carbohydrates
• fats and oils
• proteins
• vitamin C and D
• mineral ions
• iron
• fibre ( roughage)
• water

Question 3

carbohydrates

Answer 3

Needed for: energy.
Sources: Potatoes, wheat(often made into bread or pasta), rice and maize.

Question 4

fats and oils

Answer 4

Needed for: energy, to make cell membrane. Stored under skin in adipose tissue to reduce heat loss from body to air. Provide mechanical protections for organs like kidney by forming a layer around them. Sources: cooking oil, meat, dairy product and oily fish.

Question 5

proteins

Answer 5

Needed for: to build new cells for growth, to make hemoglobin, insulin, and antibodies.
Sources: meat, fish, eggs, dairy products, peas, beans, nuts, and seeds.

Question 6

Vitamin C:

Answer 6

Needed for: to make the stretchy protein collagen found in skin and other tissues. Help tissue in good repair.
Source: citrus fruit, such as oranges, lime and raw vegetables.

Question 7

Vitamin D:

Answer 7

Needed for: helps calcium to be absorbed for making bones and teeth.
Sources: oily fish, liver, red meat, egg yolk, sun

Question 8

Calcium:

Answer 8

Needed for: bones and teeth and blood clotting.
Source: Milk and other daily products, bread.

Question 9

iron:

Answer 9

Needed for: making hemoglobin the red pigment in blood, which carries oxygen.
Source. liver, red meat, egg yolk, dark green vegetables.

Question 10

fibre (roughage)

Answer 10

Needed for: Absorb and remove, toxins, prevent constipation.
Source: all plant food such as fruits and vegetables.

Question 11

water

Answer 11

Needed for: An important solvent. Metabolic reaction can only take place in
a solution. Plasma is mostly water. Cytoplasm is mostly water. To dissolve
enzymes and nutrients in alimentary canal.
Source: By drinking fluid and some fruits.

Question 12

Vitamin C deficiency causes scurvy

Answer 12

which causes pain in joints and muscles and
bleeding from gums and other places. This used to be a common disease for sailors who had no fresh vegetables during long voyages.

Question 13

Vitamin D deficiency causes

Answer 13

rickets, in which the bones become soft and deformed;
this disease was common in young children in industrial areas, who rarely got out
into the sunshine.

Question 14

Calcium deficiency results in

Answer 14

brittle bones and teeth; poor blood clotting.

Question 15

Iron defficiency causes

Answer 15

anaemia, in which there are not enough red blood cells so the
tissues do not get enough oxygen delivered to them.

Question 16

Ingestion

Answer 16

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

Question 17

digestion

Answer 17

the breakdown of food

Question 18

absorption

Answer 18

the movement of nutrients from the intestines into the blood

Question 19

assimilation

Answer 19

uptake and use of nutrients by cells

Question 20

egestion

Answer 20

the removal of undigested food from the body as faeces.

Question 21

Oesophagus

Answer 21

Food travels down the oesophagus into the stomach.

Question 22

Stomach:

Answer 22

Contains strong muscular walls. Muscles relax and contract to mix food enzyme and mucus.
Goblet cells in the walls secret mucus.
Digest protein.
Produce hydrochloric acid. Hydrochloric acid lowers the pH to about 2, which is the optimum pH for protease in the stomach. After the Stomach, the food moves into the duodenum.

Question 23

Small intestine:

Answer 23

Duodenum:
Mix food with bile and pancreatic juice.
Absorption of minerals, and other nutrients begins in the duodenum.
Ileum:
Absorb digested nutrients into blood.
Absorb water.

Question 24

Large intestine:

Answer 24

Colon:
absorb remaining water
Rectum:
Store faeces.

Question 25

Salivary gland secrete

Answer 25

saliva in mouth, which contains the enzyme amylase, that
starts the digestion of a starch.

Question 26

Pancreas secretes

Answer 26

digestive juices, which helps in digestion of fat

Question 27

Liver produces bile

Answer 27

It is stored in gallbladder. Bile increase the pH of acidic food
from the stomach. And emulsifies fat.

Question 28

More water is absorbed in small intestine than

Answer 28

large intestine.

Question 29

Physical digestion

Answer 29

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

Question 30

Physical digestion increases the

Answer 30

surface area of food for the action of enzymes in
chemical digestion.

Question 31

The tooth is embedded in the

Answer 31

gum

Question 32

Incisors

Answer 32

chisel shaped for biting off pieces of food.

Question 33

Canines

Answer 33

very similar to incisors in humans.

Question 34

Premolars

Answer 34

have wide surfaces for grinding food.

Question 35

Molars, like premolars, are used for

Answer 35

grinding

Question 36

Muscular walls of the stomach, mix the

Answer 36

food, enzyme and mucus together in the process of churning.

Question 37

Chemical digestion

Answer 37

break down of large insoluble molecules into small soluble
molecules

Question 38

The role of chemical digestion

Answer 38

producing small soluble molecules that can be
absorbed.

Question 39

Amylase breaks down

Answer 39

starch to maltose. It is secreted by salivary glands in mouth
and by pancreas in duodenum

Question 40

Maltase breaks down

Answer 40

maltose to glucose. Maltase is secreted by the cells in the
lining of the small intestine on the membranes of the epithelium lining of the small intestine.

Question 41

Pepsin breaks down

Answer 41

protein in acidic conditions and is secreted by the walls of the
stomach

Question 42

Trypsin breaks down

Answer 42

rotein in alkaline conditions and is secreted by the pancreas
in the duodenum.

Question 43

Lipase breaks down

Answer 43

fats and oils to fatty acids and glycerol. It is secreted by the
pancreas in the duodenum.

Question 44

The function of hydrochloric acid in gastric juice is to

Answer 44

kill harmful microorganisms in food and provide an acidic pH for optimum enzyme activity

Question 45

Bile

Answer 45

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

Question 46

Small intestine is the

Answer 46

region where nutrients are absorbed.

Question 47

Most water is absorbed from the small intestine but some is also absorbed from the

Answer 47

colon

Question 48

Villi and microvilli increase the

Answer 48

internal surface area of the small intestine and help in
faster absorption of dissolved nutrients.

Question 49

Villi

Answer 49

are tiny projections on the internal wall of the small intestine. The cell membrane on the surface of each villus is folded to form many tiny microvilli. Villi contains lacteal and blood capillaries.

Question 50

Capillaries in villi

Answer 50

absorb glucose, amino acids, fatty acids, glycerol, vitamins, mineral ions and water. These blood capillaries join to form hepatic portal vein, which takes all of these substances to the liver.

Question 51

The fatty acids and glycerol pass

Answer 51

into the lacteals. The contents of the lacteals are eventually emptids into the blood.