Biological molecules

Question 1

What are carbohydrates made out of

Answer 1

Made up of elements carbon, hydrogen and oxygen. H:O –> 2:1

Question 2

Single sugar will be

Answer 2

Absorbed into body cells to release energy

Question 3

Examples of single sugars

Answer 3

Glucose, fructose and galactose

Question 4

Double sugars will be

Answer 4

Stored as complex carbohydrates

Question 5

Examples of double sugar

Answer 5

Maltose and sucrose

Question 6

Double sugars always consists of

Answer 6

1 glucose molecule minimum

Question 7

Maltose consists of

Answer 7

2 glucose molecules

Question 8

Maltose –> glucose + glucose. What is the arrow

Answer 8

Digestion

Question 9

glucose + glucose –> maltose

Answer 9

Condensation

Question 10

Glucose + fructose –>

Answer 10

Sucrose

Question 11

A double sugar can split into two single sugar molecules by using

Answer 11

Enzymes (organic molecule), process is digestion

Question 12

Procedure of Benedict solution

Answer 12

1. Place 2cm^3 of each food sample into test tube. 2.add 2cm^3 of Benedict solution to food sample. 3. Mix and place test tube in boiling water bath for 3 minutes. 4. Record colour of mixture

Question 13

Positive Benedict test signifies

Answer 13

A presence of reducing sugar

Question 14

Blue solution=

Answer 14

No reducing sugar

Question 15

Green precipitate

Answer 15

Very small amount of reducing sugar

Question 16

Yellow or orange precipitate

Answer 16

Moderate amount of reducing sugar

Question 17

Red precipitate

Answer 17

Large amount of reducing sugar

Question 18

Complex carbohydrates has

Answer 18

Many glucose molecules

Question 19

Starch structure

Answer 19

Straight chain of glucose molecules

Question 20

Role of starch

Answer 20

Storage form of carbohydrates in plants, digested to glucose for respiration to release energy for cell activities

Question 21

Starch occurence

Answer 21

Tubers, in green leaves, tapioca

Question 22

Structure of cellulose

Answer 22

Bonds between glucose different from starch

Question 23

Role of cellulose

Answer 23

Cannot be digested, serve as dietary fibre

Question 24

Cellulose occurrence

Answer 24

Cell walls

Question 25

Glycogen structure

Answer 25

Branched molecule, many glucose molecules joined together.

Question 26

Role of glycogen

Answer 26

Storage form of carbohydrates in mammals. Digested to glucose for respiration to release energy for cell activities

Question 27

Glycogen occurrence

Answer 27

Liver and muscles of mammals

Question 28

Main store of glucose in mammals

Answer 28

Glycogen (accessible source)

Question 29

Glycogen and starch are suitable storage materials in cells because

Answer 29

Insoluble in water so they do not change the water potential in cells. Easily be broken down (hydrolysed) to glucose for respiration. Compact so they occupy less space

Question 30

Functions of carbohydrates

Answer 30

Substrate for respiration like cell wall in plants, converted into amino acids, formation of nucleic acids like DNA. Synthesiser lubricants like mucus (consists of carbo and protein), synthesise nectar in some flowers

Question 31

How to test for starch

Answer 31

Iodine test

Question 32

Procedure of iodine test

Answer 32

Add a 2-3 drops of iodine solution and record observations

Question 33

Brown to blue black solution equates to

Answer 33

Positive presence of starch

Question 34

Negative test for iodine test

Answer 34

Brown solution

Question 35

What are fats made out of

Answer 35

Elements of hydrogen, carbon and oxygen, little oxygen it contains in proportion to hydrogen

Question 36

fats can be broken down into

Answer 36

1 glycerol and 3 fatty acids

Question 37

fat functions as

Answer 37

long term storage of energy, insulating material that prevents heat loss, solvent for fat soluble vitamins such as hormones, essential part in cell membrane and reduce water loss from skin

Question 38

how to test for fats

Answer 38

ethanol emulsion test

Question 39

white emulsion is form when

Answer 39

ethanol and water are added to fats

Question 40

procedure of ethanol emulsion (liquid)

Answer 40

2cm^3 of ethanol to liquid sample in test tube, mix, add 2cm^3 of water to mixture and record observations

Question 41

procedure of ethanol emulsion (solid)

Answer 41

crush solid sample and place in test tube, add 2cm^3 of ethanol in test tube and shake, decant (settle down) ethanol into 2cm^3 water, record

Question 42

white emulsion signifies (emulsion test)

Answer 42

presence of fats

Question 43

clear/colourless solution in emulsion test signifies

Answer 43

no presence of fats

Question 44

amino acid is made of

Answer 44

amino (-NH2) and acid (-COOH) group

Question 45

presence of NH2 signifies

Answer 45

protein

Question 46

change of arrangement of amino acids equates to

Answer 46

total change in protein type

Question 47

amino acids are known as

Answer 47

simple molecules and most useful form

Question 48

amino acids are absorbed into the body cells for

Answer 48

energy and chemical reactions

Question 49

protein --> polypeptide --> amino acids

Answer 49

digestion (other way is assimilation)

Question 50

functions of proteins

Answer 50

growth and repair of worn out body cells, synthesis of enzymes and hormones, formation of antibodies

Question 51

test for proteins

Answer 51

food sample

Question 52

food sample procedure

Answer 52

2cm^3 of liquid food sample, add an equal volume of biuret solution, shake well

Question 53

violet solution indicates (food sample)

Answer 53

presence of proteins

Question 54

blue solution indicates (food sample)

Answer 54

no presence of proteins