Exam Questions Paper 1 Bio

Question 1

How to test for non reducing

Answer 1

1.Heat with acid and neutralise
2.Heat with Benedict’s solution
3.red precipitate if present

Question 2

Role of dna polymerase in dna replication

Answer 2

Joins the adjacent nucleotides on new strand via condensation reaction

Question 3

Semi conservative replication

Answer 3

1.Dna helicase breaks down hydrogen bonds between complementary bases
2.Two strands act as a template
3.Dna nucleotides attached to exposed complementary base pairing
4.Dna polymerase joins adjacent nucleotides on new strand via condensation reaction
5.two daughter cells

Question 4

Water

Answer 4

Solvent -reaction occurs faster
Polar molecule- acts as a solvent
Metabolite -water is reactive
Strong cohesion -this supports the water columns

Question 5

Give two ways which the structure of starch is similar to cellouse

Answer 5

1. There both polysaccharides
2. Monomers are linked by glycosidic bonds

Question 6

Give two ways in which the structure of starch is different from cellulose

Answer 6

1. Starch is a polymer of a-glucose
   2.strach is coiled

Question 7

Explain the difference in the structure of the starch molecule and cellulose molecule shown in disarray above

Answer 7

1. Starch is a polymer of a-glucose , whilst cellulose is a polymer of b-glucose
2. Hydroxyl and hydrogen groups on carbon 1 are inverted

Question 8

Explain one way in which starch molecules are adapted for their function in plant cells

Answer 8

Starch molecules are helical so are very compact

Question 9

Explain how cellulose molecules are adapted for their function in pant cells

Answer 9

1. Cellulose are long and straight
2. Which are linked by hydrogen bonds this forms fibres called fibrils
3. Which provide strength to cellulose can support cell wall

Question 10

Monosaccharides and disaccharides taste sweet
The lactose free milk made after hydrolysis with lactase taste sweeter than the cows milk containing lactose
Suggest why

Answer 10

1. Lactose is hydrolysed to glucose and galactose
2. More sugar molecules are present

Question 11

Which part of a phospholipid bilaterally is formed from a particular molecule

Answer 11

Glycerol

Question 12

Explain the importance of maintaining a constant blood ph 3marks

Answer 12

Enzymes in the blood are sensitive to changes in ph
Changes in oh can change the tertiary structure of the active site
This means that fewer enzyme substrate complex can be formed

Question 13

Suggest how binding of cyanide to cytochrome oxidases the affects of enzymes

Answer 13

Cyanide acts as a competitive inhibitor
so blocks the active site of cytochrome oxidases
This means fewer enzyme substrate complex can be formed