Food

Question 1

What is a balanced diet?

Answer 1

• A diet that provides enough of these substances and in the correct proportions to keep you healthy.

Question 2

What are carbohydrates used for and how is it released?

Answer 2

• They are the body’s main fuel for supplying cells with energy.
• Cells release this energy by oxidising a sugar called glucose.

Question 3

What is starch?

Answer 3

• It is a large, insolube molecule.
• It is a polymer of glucose (made up of long chains of hundreds of lgucose molecules joined together)

Question 4

What is the similar carbohydrate of starch found in animal cells?

Answer 4

• Glycogen

Question 5

What is another polymer of glucose that humans cannot digest?

Answer 5

• Cellulose
• Makes up plant cell walls

Question 6

What do humans often use cellulose for?

Answer 6

• Forms dietary fibre
• Gives muscles of gut something to push against as the food is moved through the intestine.
• Keeps the gut contetns moving, avoiding constipationa nd helping to prevent serious diseases of the intestine.

Question 7

What are single sugars called and what are some examples?

Answer 7

• Monosaccharides
• Glucose and fructose

Question 8

What are disaccharides?

Answer 8

• Two monosaccharides (glucose and fructose) joined together
• E.g. Sucrose

Question 9

What are polysaccharides?

Answer 9

• Polymers of sugars
• Such as starch and glycogen

Question 10

What are lipids needed for?

Answer 10

• Form an essential part of the structure of all cells
• Fat is deposited in certain parts of the body as a long-term store of energy.

Question 11

What does the fat layer under the skin act as?

Answer 11

• As insulation, reducing heat loss through the surface of body.
• Fat around organs to protect them from mechanical damage

Question 12

What are lipids made out from?

Answer 12

• A molecule of glycerol joined to three fatty acid molecules

Question 13

What is kwashiorkor?

Answer 13

• A protein-defiency disease

Question 14

What are proteins made up of?

Answer 14

• 20 different sub-units called amino acids

Question 15

What is the structure of a protein?

Answer 15

• The amino acids are linked together in chains, which are usually folded up or twisted into spirals, with cross-linls holding the chains together.

Question 16

What examples of proteins are there?

Answer 16

• Structural proteins, e.g. collagen and kertin in skin and nails
• Specific functions, e.g. enzymes and haemoglobin

Question 17

What is calcium used for in the body?

Answer 17

• Making teeth and bones

Question 18

What is phosphorus used for in the body?

Answer 18

• Making teeth and bones
• Part of many chemicals, e.g. DNA

Question 19

What is sodium used for in the body?

Answer 19

• In body fluids, e.g. blood

Question 20

What is chlorine used for in the body?

Answer 20

• In body fluids, e.g. blood

Question 21

What is magnesium used for in the body?

Answer 21

• Making bones
• Found inside cells

Question 22

What is iron used for in the body?

Answer 22

• Part of haemoglobin in red blood cells, helps carry oxygen

Question 23

What will people who don’t get enough of a mineral in their diet develop?

Answer 23

• Mineral deficieny disease

Question 24

What happens if a young child doesn’t consume the right amount of calcium every day?

Answer 24

• The bones will become deformed, rsulting in rickets.

Question 25

What happens if a person doesn’t get enough iron in their diet?

Answer 25

• They cannot make enough haemoglobin for their red blood cells.
• Causes anaemia, where you become tired and lack energy, becasue their blood doesn’t carry enough oxygen.

Question 26

What is the use in the body of vitamin A?

Answer 26

• Makes a chemical in the reetina
• Also protects the surface of the eye

Question 27

What is the effect of a deficiency of vitamin A?

Answer 27

• Night blindness
• Damaged cornea of eye

Question 28

What is the use in the body of vitamin B1?

Answer 28

• Helps with cell respiration

Question 29

What is the effect of a deficiency of vitamin B1?

Answer 29

• Beri-beri

Question 30

What is the use in the body of vitamin B2?

Answer 30

• Helps with cell respiration

Question 31

What is the effect of a deficiency of vitamin B2?

Answer 31

• Poor growth
• Dry skin

Question 32

What is the use in the body of vitamin B3?

Answer 32

• Helps with cell respiration

Question 33

What is the effect of a deficiency of vitamin B3?

Answer 33

• Pellagra (dry red skin, poor growth,a nd digestive disorders)

Question 34

What is the use of vitamin C in the body?

Answer 34

• Sticks together cells lining surfaces such as the mouth

Question 35

What is the effect of a deficiency of vitamin C?

Answer 35

• Scurvy

Question 36

What is the use in the body of vitamin D?

Answer 36

• Helps bones absorb calcium and phosphate

Question 37

What is the effect of deficiency of vitamin D?

Answer 37

• Rickets, poor teeth

Question 38

What is the test for starch?

Answer 38

• Place starch on a white, spotting tile.
• Add a drop of dilute iodine solution to the starch.
• The iodine should react witht he starch, forming a very dark blue or ‘blue-black’ colour.

Question 39

What is the test for glucose?

Answer 39

• Add a small spatula of glucose in a test tube.
• Add a little water.
• Shake the tube to dissolve the glucose.
• Add several drops Benedict’s solution to the tube, enough to coloru the mixture blue.
• A water bath is prepared by ahlf-filling a beaker with water and heating it.
• Place the test tube in the beaker and allow the water to boil.
• After a few seconds the clear blue solution shuld gradually change colour, forming a cloudy orange or ‘brick red’ precipitate.

Question 40

What type of sugar will the test for glucose work with?

Answer 40

• Reducing sugars, e.g. fructose and lactose.
• Won’t work with sucrose

Question 41

What solution is reduce in the test for glucose and what is it reduced to?

Answer 41

• Copper (II) sulfate ——> copper (I) oxide