topic 5 - biological molecules and diet

Question 1

what elements does carbohydrates contain

Answer 1

• carbon
• hydrogen
• oxygen

Question 2

definition of monosaccharide

Answer 2

simple sugars, e.g. glucose and fructose

Question 3

definition of disaccharide

Answer 3

made when 2 monosaccharides joins together, e.g. maltose ( formed by 2 glucose molecules )

Question 4

definition of polysaccharide

Answer 4

made when lots of monosaccharides joins together, e.g. starch, glycogen and celluose

Question 5

what elements does protein contain

Answer 5

• carbon
• hydrogen
• oxygen
• nitrogen

Question 6

what is proteins formed from

Answer 6

long chains of amino acids

Question 7

examples of proteins

Answer 7

• enzymes
• haemoglobin

Question 8

what elements does lipids contain

Answer 8

• carbon
• hydrogen
• oxygen

Question 9

what is lipids formed from

Answer 9

fatty acid and glycerol

Question 10

elements, monomer and function of starch

Answer 10

elements: Carbon, Hydrogen, Oxygen
monomer: glucose
function: stores carbohydrates in plants

Question 11

elements, monomer and function of glycogen

Answer 11

elements: Carbon, Hydrogen, Oxygen
monomer: glucose
function: stores carbohydrates in animals

Question 12

elements, monomer and function of cellulose

Answer 12

elements: Carbon, Hydrogen, Oxygen
monomer: glucose
functions: main component of a cell wall

Question 13

the necessary food groups

Answer 13

• carbohydrates
• protein
• lipids
• dietary fibre
• vitamins
• minerals
• water

Question 14

causes and effect of starvation

Answer 14

cause: taking in less energy than is used

effect: severe weight loss, damage to heart + immune system

Question 15

cause and effect of coronary heart disease

Answer 15

cause: diet too high in saturated fat and cholesterol

effect: fat deposits builds up and reduces flow of blood to heart muscle cells, leading to heart attacks and deaths.

Question 16

cause and effect of constipation

Answer 16

cause: lack of fibre in the diet

effect: increased risk of bowel cancer

Question 17

cause and effect of obesity

Answer 17

cause: taking in more energy than is used

effect: extra energy is stored as fat and weight increases, increasing risk of heart diseases and diabetes

Question 18

function and sources of carbohydrates

Answer 18

function: source of energy

sources: pasts, rice, bread, potatoes

Question 19

functions and sources of protein

Answer 19

function: growth and repair of tissues

sources: meat, fish, cheese, egg

Question 20

functions and sources of lipids

Answer 20

function: provide and store energy, insulations

sources: butter, oil, oily fish

Question 21

functions and sources of dietary fibre

Answer 21

function: aids the movement of food through the gut

sources: vegetables, fruits, whole grains

Question 22

functions and sources of vitamin A

Answer 22

function: improves vision, keep skin and hair healthy

sources: Liver, carrots, dairy products

Question 23

functions and sources of vitamin C

Answer 23

function: prevents scurvy, make fibre that bonds cell together in tissues

sources: citrus fruits, vegetables

Question 24

functions and sources of vitamin D

Answer 24

function: calcium absorption

sources: eggs, oily fish, made by body from sunlight

Question 25

functions and sources of calcium

Answer 25

function: make bones and teeth, prevents osteoporosis sources: milk, cheese

Question 26

functions and sources of Iron

Answer 26

function: makes haemoglobin sources: red meat, beans

Question 27

function and sources of Water

Answer 27

function: make cytoplasm and blood, remove waste products from body sources: foods and drinks

Question 28

definition of balanced diet

Answer 28

a diet that contains all the essential nutrients plus fibre in the right proportions

Question 29

what factors affect energy requirements

Answer 29

- age - height - sex - activity levels - pregnancy - breast feeding

Question 30

how does activity levels affect energy requirements

Answer 30

- the more active, the more energy required - more muscles contractions, respiring faster

Question 31

how does sex affect energy requirements

Answer 31

- proportion of muscles compared to fat - men has more muscles and therefore need more energy

Question 32

how does pregnancy affect energy requirements

Answer 32

- needs energy to support the growth of developing fetus - larger mass - needs more calcium and iron

Question 33

how does breast feeding affect energy requirements

Answer 33

- need more calcium to make high-quality breast milk

Question 34

how does age affect energy requirements

Answer 34

- children need more energy to grow - tend to be more active

Question 35

describe the test for glucose

Answer 35

reagent: Benedict Colour of reagent: light blue process: add few drops of Benedicts solution to glucose and water. put the test tube in water bath positive result: brick-red negative result: blue

Question 36

describe the test for Starch

Answer 36

reagent: Iodine Colour of reagent: orange-brown process: put iodine on spotting tile and add iodine to it positive result: blue-black negative result: orange-brown

Question 37

describe the test for protein

Answer 37

reagent: biuret colour of reagent: blue process: add powered food sample and water to test tube and shake it. add biuret solution and shake again positive result: Lilac negative result: blue

Question 38

describe the test for lipids

Answer 38

reagent: ethanol colour of reagent: colourless process: put oil and ethanol to a test tube and shake it. pour the solution into water positive result: cloudy emulsion negative result: colourless

Question 39

describe the test for lipids 2

Answer 39

reagent: sudan 3 colour of reagent: reddish brown process: add sample food and sudan 3 stain solution to a test tube and shake it. positive result: mixture splits into 2 layers and the top one turns bright red negative result: no separate red layer

Question 40

hazards of the food tests

Answer 40

- iodine irritant to eyes - biuret contains copper (II) Sulfate, dangerous to eyes - Biuret contains Sodium Hydroxide, corrosive - ethanol is flammable

Question 41

formula for amount of energy in food in J

Answer 41

mass of water x temperature change of water x 4.2

Question 42

formula for amount of energy in food in J per gram

Answer 42

( mass of water x temperature change of water x 4.2 ) / mass of sample food