nutrients

Question 1

definition of nutrients

Answer 1

chemical substances in food that provide energy and materials needed by the body

Question 2

what elements are carbohydrates made up of?

Answer 2

carbon, hydrogen, oxygen

Question 3

three monosaccharides

Answer 3

glucose, fructose, galactose

Question 4

three disaccharides

Answer 4

sucrose, maltose, lactose,

Question 5

condensation reaction

Answer 5

a chemical reaction in which 2 molecules are joined together to form a larger molecule with the removal of one molecule of water

Question 6

hydrolysis / hydrolytic reaction

Answer 6

a chemical reaction in which a water molecule is needed to break up a complex molecule into smaller molecules

Question 7

three polysaccharides and each of its function

Answer 7

starch - made and stored in plants
glycogen - made and stored in animals
cellulose - forms main parts of the cell wall

Question 8

elements that proteins are made up of

Answer 8

carbon, hydrogen, oxygen, nitrogen

Answer 9

• insoluble in water
• large molecules and cannot diffuse through cell membrane
• can be easily hydrolysed to glucose when needed

Question 10

anino acids are the…

Answer 10

building blocks of protein

Question 11

what happens to the animo acids when formed into polypeptides?

Answer 11

animo acids link up to form polypeptides

Question 12

how to get a complex and 3D shape from amino acids?

Answer 12

chains are coiled or folded giving the protein a more complex and 3D shape

Question 13

what happens when the amino acid bonds are broken?

Answer 13

the protein loses its three-dimensional shape
protein has been denatured

Question 14

what elements are fats made up of?

Answer 14

carbon, hydrogen, oxygen

Question 15

what makes up one fat molecule?

Answer 15

1 glycerol and 3 fatty acids

Question 16

how to test for reducing sugar?

Answer 16

Benedict’s Test
1) add 2cm3 of Benedict’s Solution to 2cm3 of glucose solution (reducing sugar)
2) shake the mixture
3) Leave the test tube in a breaker of boiling water for 5 minutes

(blue to green -> traces of reducing sugar)
(blue to yellow -> moderate amt of reducing sugar)
(blue to brick red -> large amt of reducing sugar)

Question 17

how to test for starch?

Answer 17

Iodine test
- Add a few drops of iodine to the sample
(turns dark-blue/ blue-black -> starch present)
(remains brown -> starch not present)

Question 18

how to test for fats?

Answer 18

ethanol emulsion test
1) add 2cm3 of ethanol to a drop of liquid food/ solid food and shake the mixture throughly
2) add 2cm3 of wated to the mixture and shake the mixture
(cloudy white emulsion formed -> fats present)
(no cloudy white emulsion formed -> fats absent)

Question 19

how to test for proteins?

Answer 19

biuret test
1) add 1cm3 of sodijm hydroxide to 2cm3 of egg white solution
2) add 1% copper(II) sulfate solution, drop by drop, shaking after every drop
3) shake well and allow mixture to stand for 5 minutes
(mixture turns violet -> proteins present)
(mixture remains blue -> proteins absent)

Question 20

5 reducing sugars

Answer 20

Lactose
Glucose
Maltose
Fructose
Galactose