Nutrition in Humans

Question 1

function of carbohydrates

Answer 1

provides energy

Question 2

function of lipids

Answer 2

provide energy, act as an energy store and provide insulation

Question 3

function of VITAMIN A

Answer 3

found in liver. helps to improve vision and keep skin and hair healthy

Question 4

function of VITAMIN C

Answer 4

prevents scurvy. healthy immune system

Question 5

function of VITAMIN D

Answer 5

Found in eggs and sunlight. needed for calcium absorption

Question 6

function of calcium

Answer 6

needed to make bones and teeth

Question 7

function of iron

Answer 7

needed to make haemoglobin for healthy blood

Question 8

function of water

Answer 8

• every bodily function relies on water.

- we need a constant supply to replace water loss through urinating, breathing and sweating

Question 9

function of fibre

Answer 9

aids movement of food through gut

Question 10

how does amount of energy needed vary for different people?

Answer 10

1. activity level= more active needs more energy
2. age= children and teenagers need more energy as they are growing
3. pregnancy= pregnant women need more energy for their babies to develop

Question 11

function of mouth

Answer 11

• salivary glands in mouth produce AMYLASE enzyme in the salvia
• teeth break down food

Question 12

function of oesophagus

Answer 12

muscular tube that connects the mouth and stomach

Question 13

function of liver

Answer 13

where bile is produced

Question 14

function of gall bladder

Answer 14

where bile is stored

Question 15

function of large intestine

Answer 15

aka colon. where excess water is ABSORBED from the food.

Question 16

function of rectum

Answer 16

last part of large intestine. where faeces are stored before being excreted.

Question 17

function of stomach

Answer 17

1. pummels food with its muscular walls
2. produces the protease enzyme PEPSIN
3. produces hydrochloric acid for 2 reasons:
   
   • to kill bacteria
   • to give the optimum pH for the protease enzyme to work (pH 2)

Question 18

function of pancreas

Answer 18

produces protease, amylase and lipase enzymes. releases them into the small intestine

Question 19

function of small intestine

Answer 19

produces protease, amylase and lipase enzymes to complete digestion.
also where nutrients are absorbed of the alimentary canal into the body.

Question 20

how is the small intestine adapted for the absorption of food?

Answer 20

1. very long= so there’s time to break down and absorb all the food before it reaches the end.
2. really big SA for absorption because walls of small intestine are covered in millions of villi.
3. each cell on the surface of a villus has its one microvilli (tiny projections that increase the SA even more)
4. villi have a single permeable layer of surface cells and a very good blood supply to assist quick absorption.

Question 21

how is food moved through the gut?

Answer 21

• PERISTALSIS.
• there is muscular tissue all the way down the alimentary canal.
• it’s job is to squeeze balls of food (boluses) through the gut, otherwise it would get clogged. this squeezing, which is waves of circular muscle contractions, is called peristalsis.

Question 22

what do digestive enzymes do?

Answer 22

break down BIG MOLECULES (eg starch, proteins and fats) into small molecules so they can pass through the walls of the digestive system.

Question 23

what do amylase and maltase do?

Answer 23

• AMYLASE converts STARCH into MALTOSE.

- MALTASE converts MALTOSE into GLUCOSE.

Question 24

what does protease do?

Answer 24

converts PROTEINS into AMINO ACIDS

Question 25

what does lipase do?

Answer 25

converts LIPIDS into FATTY ACIDS and GLYCEROL.

Question 26

what does bile do?

Answer 26

neutralises stomach acids and emulsifies fats.

Question 27

where is bile produced and stored?

Answer 27

produced in liver and stored in gall bladder before it’s released into the small intestine.

Question 28

how does bile neutralise stomach acid?

Answer 28

• the hydrochloric acid in the stomach makes the pH too acidic for enzymes in the small intestine to work properly.
• bile is ALKALINE- it neutralises the acid and makes conditions alkaline.
• the enzymes in the small intestine work best in alkaline conditions.

Question 29

how does bile emulsify fats?

Answer 29

• it breaks the fat into tiny droplets.

- this gives a much bigger SA of fat for the lipase enzyme to work on which speeds up digestion.