June 2010 wjec Unit 1

Question 1

What possess nucleic acid?

Answer 1

Bacterium
Virus

Question 2

What surrounded by a protein coat?

Answer 2

virus
not a bacterium

Question 3

What has ribosomes in the cytoplasm?

Answer 3

Bacterium
not a virus

Question 4

What group of protein does collagen belong?

Answer 4

Fibrous

Question 5

Describe the structure of a collagen molecule?

Answer 5

polypeptide chains
3 chains
3 alpha helices
tightly bound
held together by H bonds

Question 6

1 function of collagen?

Answer 6

structural

Question 7

3 differences between collagen + haemoglobin that you can see in the diagrams?

Answer 7

4 chains vs 3
compact vs non compact
3 polypeptide chains the same vs 2 different polypeptide chains
secondary vs quarternary

Question 8

1 other type of globular protein

Answer 8

hormones

Question 9

Why is the mass of product formed at 60 degrees is greater during the first 5 minutes than the masses formed at 25 degrees ad 37 degrees

Answer 9

at higher temps, enzymes have more kinetic energy
more enzyme substrate complexes are formed
more products are formed

Question 10

Why is there less overall product formed a 60 degrees at 37 degrees?

Answer 10

enzyme reacts rapidly
gradual denaturation of enzyme occurs
all substrate is not reacted

Question 11

Why is the mass of product formed at 37 degrees levels off after approx 20 minutes

Answer 11

all substrate is converted to product

Question 12

Why is the curve at 25 degrees not levelled off after 60 minutes?

Answer 12

some substrate remains after 60 mins

Question 13

2 advantages of immobilised enzymes?

Answer 13

can be re used
greater stability
more than 1 enzyme can be used
can be used in a continuous reaction

Question 14

Why is this diagnostic method is not suitable for the accurate measurement of the concentration of glucose in the urine?

Answer 14

colour change only indicates if present or absent

Question 15

Biosensor def?

Answer 15

measures metabolite by converting chemical signal to electrical signal

Question 16

What is the function of the enzyme?

Answer 16

combines with substrate at active site to produce product

Question 17

Biosensor can be used to measure blood glucose conc?

Answer 17

glucose from blood diffuses into gel acted on by glucose oxidase
amount of product is directly proportional to glucose concentration
electrode is activated by product
generates electrical signal
size of potential is directly proportional to mass of product

Question 18

Secretory vesicle and cell involved in absorption?
x - secretory cell
y - involved in absorption

Answer 18

x does not contain microvilli whereas Y contains microvilli
X contains large amount of ribosomes whereas Y has less amount of ribosomes
X contains large numbers of vesicles whereas Y does not contain vesicles

Question 19

Vesicles?

Answer 19

Transport substances to plasma

Question 20

Ribosomes?

Answer 20

Protein synthesis;

Question 21

Mitochondrion?

Answer 21

site of ATP synthesis

Question 22

Exocytosis?

Answer 22

Transport vesicle fuses with plasma membrane
Break in membrane to allow expulsion of secretion

Question 23

What is the site of energy release in mammals?

Answer 23

Mitochondrion

Question 24

Advantage of storing lipid rather than carbohydrate?

Answer 24

Higher energy yield per unit mass

Question 25

Disadvantage of storing lipid rather than carbohydrate?

Answer 25

Oxygen required for respiration

Question 26

2 reasons why mammals store lipids?

Answer 26

thermal insulation
buoyancy
protection of delicate internal organs

Question 27

2 uses for protein in growing potato plant?

Answer 27

new tissue manufacture
enzyme manufacture

Question 28

What is meant by the term hydrolysed?

Answer 28

chemical insertion of water in order to break a bond

Question 29

Products for the complete hydrolysis of starch?

Answer 29

glucose

Question 30

Products for the complete hydrolysis of protein?

Answer 30

amino acids

Question 31

1 problem in performing any investigation using blood?

Answer 31

blood clots/infection

Question 32

Why haemolysis of the red blood cells occurred quickest when placed in distilled water?

Answer 32

water has the highest water potential
water passes down water potential from high water potential to lower water potential by osmosis

Question 33

Expected appearance of one of the blood cells after 5 minutes + explain its appearance?

Answer 33

water passes out of cell, which causes a shrinkage of cells
therefore cells become Plasmolysed