Section 2 - Human Nuturition

Question 1

What elements do carbohydrate molecules contain (3)

Answer 1

• Hydrogen - Oxygen - Carbon

Question 2

Starch and glucose are large, …… carbohydrates, made up of many smaller units, joined together in a …. ……

Answer 2

• complex - long chain

Question 3

What are proteins made up of (2)

Answer 3

• Amino Acids
• Long chains

Question 4

What elements do amino acids contain (4)

Answer 4

• Carbon - Nitrogen - Hydrogen - Oxygen

Question 5

What are lipids made up of (2)

Answer 5

• Fatty acids - Glycerol

Question 6

What elements do lipids contain (3)

Answer 6

• Carbon - Hydrogen - Oxygen

Question 7

Describe how to test for glucose (5)

Answer 7

• Benedict’s test
• Add blue Benedict’s reagent to a sample and heat it
• Make sure the solution doesn’t boil
• If glucose is present, it will forma a coloured precipitate
• The higher the conc of glucose, the further the colour change goes (use to compare)

Question 8

For the Benedict’s test, what are the colours for varying conc’s of glucose (3)

None -

Low -

High

Answer 8

Question 9

Describe how to test for starch (2)

Answer 9

• Add iodine solution
• If starch is present, sample changes from brown/orange to a dark, blue/black colour

Question 10

What are the 5 essential nutrients (5)

Answer 10

• Carbs
• Protein
• Fats
• Vitamins & Minerals
• Water

+ Fibre

Question 11

What is the function of Vitamin A, C and D and what are they found in (6)

Answer 11

Vitamin A - Liver - Improve vision, keep your skin and hair healthy

Vitamin C - Oranges - Prevent scurvy

Vitamin D - Eggs - Needed for calcium absorption

Question 12

What 2 mineral ions de we need, what are their functions and what can we find them in (6)

Answer 12

Calcium - Milk, cheese - make bones and teeth

Iron - Red meat - needed to make haemoglobin for healthy blood

Question 13

What is dietary fibre’s function and what is it found in (2)

Answer 13

• Aids the movement of food through the gut
• Wholemeal bread

Question 14

Describe an experiment to show how much energy is in food (9)

Answer 14

• Find a food that burn’s easily; a peanut
• Weigh a small amount of the food and then skewer it with a mounted needle
• Add 25cm3 of water to a boiling tube, and measure its temperature
• Set fire to the food using a bunsen burner
• Hold the burning food under the boiling tube until it goes out
• Relight and hold again, until no longer possible
• Measure the temperature of the water

Use : 25 x temp change x 4.2 = energy in food

Use : energy/mass = energy per gram of food (J/g)

Question 15

Describe a way to make the energy from food practical more accurate (2)

Answer 15

• Insulate the boiling tube with foil
• Minimises heat loss and keeps more energy in the water

Question 16

Why are digestive enzymes needed in the body (3)

Answer 16

• Digestive enzymes break down big insoluble molecules into smaller soluble ones
• Starch, proteins and fats are too big to pass through the walls of the digestive system
• Digestive enzymes allow starch, proteins and fats to be soluble and pass through the walls of the digestive system to be digested

Question 17

The digestive enzyme ……. converts starch into …….

Answer 17

Amylase

Maltose

Question 18

The digestive enzyme ……. converts maltose into …….

Answer 18

maltase

glucose

Question 19

The digestive enzyme ……. converts proteins into …….

Answer 19

protease

amino acids

Question 20

The digestive enzyme ……. converts lipids into ……. and ……..

Answer 20

Lipase

Fatty acids and glycerol

Question 21

Where is bile produced, stored and released into (3)

Answer 21

Produced - liver

Stored - gall bladder

Released into small intestine

Question 22

What does bile do (3)

Answer 22

• Bile neutralises hyrdochloric acid in the stomach
• Allowing enzymes in the small intenstine to work properly
• Bile emulsifies fats, making digestion faster as there is a bigger surface area of fat

Question 23

The ………… …….. is another name for the gut (1)

Answer 23

alimentary canal

Question 24

Label all 10 partS (10)

Answer 24

A - Mouth

B - Oesophagus

C - Liver

D - Stomach

E - Pancreas

F - Large Intestine

G - Small Intestine

H - Appendix

I - Anus

J - Gall bladder

Question 25

What is A and what is its purpose (3)

Answer 25

• Mouth
• Salivary glands produce amylase enzymes in the saliva
• Teeth break down food mechanically

Question 26

What is B and what is its purpose (2)

Answer 26

• Oesphoagus
• Muscular tube that connects the mouth and stomach

Question 27

What is C and what is its purpose (2)

Answer 27

• Liver
• Where bile is produced

Question 28

What is D and what is its purpose (4)

Answer 28

• Stomach
• Pummels food with its muscular walls
• Produces protease enzyme, pepsin
• Produces HCL;

to kill bacteria

to give the right pH for the protease enzyme to work

Question 29

What is E and what is its purpose (3)

Answer 29

• Pancreas
• Produces protease, amylase and lipase enzymes
• It releases these into the small intestine

Question 30

What is F and what is its purpose (2)

Answer 30

• Large intestine
• Where excess water is absorbed from the food

Question 31

What is G and what is its function (3)

Answer 31

• Small intestine
• Uses protease, amylase and lipase enzymes to complete digestion
• Where nutrients are absorbed out of the alimentary canal into the body

Question 32

What is I and what is its purpose (2)

Answer 32

• Anus
• Where faeces are egested

Question 33

What is J and what is its purpose (2)

Answer 33

• Gall bladder
• Where bile is stored

Question 34

What is peristalsis (3)

Answer 34

• Waves of circular muscle contractions
• Allowing food to squeeze through your gut and not get clogged
• Occurs in muscular tissue all the way down the alimentary canal

Question 35

Describe the digestive process (5)

Answer 35

• Ingestion : Food taken into your mouth
• Digestion : Break down of large, insoluble molecules to smaller soluble ones. Can be mechinal (e.g teeth) or chemical (e.g bile)
• Absorption : Digested food molecules are absorbed in the small intestine; water mainly in the large. Absorption is he process of moving molecules through the walls of the intestines in the blood
• Assimilation : When digested molecules bcome part of cells (e.g digested amino acids assimilated, used by cells to make cellular proteins
• Egestion : All the undigested molecules form faeces, you get rid of them through the anus.

Question 36

Explain how villi in the small intestine help with absorption (6)

Answer 36

• Villi found on duodenum and ileum
• It’s very long, time to break down and absorb all the food before it reaches the end
• Large surface area for absorption, because the walls are covered with millions of villi
• Villi are finger like projections which increase surface area
• Each cell on the surface of a villus has microvilli, increasing the surface area even more
• Villi have a single permeable layer of surface cells and a very good blood supply to assist quick absorptionn.

Question 37

Label the two missing parts and give their function (4)

Answer 37

Duodenum - Recieves partially digested food from the stomach, crucial role in chemical digestion

Illeum - mainly to absorb vitamin B12 and bile salts