Test

Question 1

Functions of triglycerides

Answer 1

Waxy cuticle of plants/insects= makes them waterproof

Aquatic organisms = less dense than water so stay buoyant

Blubber in whales/seals = thermal insulator conducts heat slowly to prevent excess heat loss

Stored around delicate organs = shock absorption helps protect internal organs from physical damage

Question 2

Benedicts test

Answer 2

Add 2cm³ of benedicts solution to sample and heat to 95°C

Blue to green, yellow, orange, red, brick red precipitate means there’s a reducing sugar

Boil fresh sample with dilute HCl for a few minutes

Neutralise with sodium hydrogen carbonate

Repeat benedicts test

Question 3

Test for starch

Answer 3

Iodine

Add 2 drops of potassium iodide solution to sample

Blue black colour indicates presence of starch

Question 4

Test for proteins

Answer 4

Biuret test

Add equal volumes to test tube

Blue to purple or violet

Question 5

3 types of fibrous proteins

Answer 5

Silk
Collagen
Keratin

Question 6

4 things R groups can be

Answer 6

Hydrophobic
Hydrophilic
Positive
Negative

Question 7

DNA adaptations

Answer 7

1) Helical coiled structure structure so compact
2) Large molecule so stores lots of information
3) Many weak H bonds make it strong
4) Complementary base paring for accurate replication
5) Double stranded so can have semi conservative replication and each can act as a template
6) Weak H bonds between bases for easy separation in replication
7) Sugar phosphate backbone provides strength and stability

Question 8

What does DNA polymerase bond to

Answer 8

3’ end of template strand and has an active site complementary to the 5’ end of free nucleotides

Question 9

Approximately how many molecules of haemoglobin do each erythrocyte contain

Answer 9

300 million

Question 10

Partial pressure of oxygen

Answer 10

Amount of oxygen in a mixture of gases or a solution

Question 11

Why is oxyhaemoglobin broken down in tissue cells

Answer 11

Lower partial pressure of oxygen so unloaded

Question 12

Exercise effect on dissociation curve

Answer 12

Bohr effect, CO2 makes blood more acidic so reduces affinity

Shifts to the right so more O2 unloaded at respiring cells

Question 13

Oxygen dissociation for foetus

Answer 13

Higher affinity at lower partial pressure so oxygen moves to foetus

Question 14

Why isn’t the ATP from LIR the only source of ATP

Answer 14

Not all parts of plant photosynthesis
No photosynthesis in the dark
ATP needed for active transport
More ATP needed than is produced in LIR

Question 15

What is the effect of herbicide on ETC

Answer 15

Less ATP
Less NADPH
Less GP into TP
Reduced transfer of protons across thylakoid membrane
Less independent light reaction

Question 16

Why do some photosynthesising organisms fluoresce

Answer 16

They can’t move down the ETC so release energy as light instead

Question 17

Stroma

Answer 17

Protein rich matrix surrounding thylakoids containing enzymes starch grains and ribosomes

Question 18

Thylakoid

Answer 18

Collection of flattened membrane bound sacs found in chloroplast

Question 19

Reactants vs products for glycolosis

Answer 19

Glucose

2 net ATP
2 NADH
2 Pyruvate

Question 20

Reactants vs products of link reaction

Answer 20

2 pyruvate

No ATP
2 NADH
2 CO2
2 Acetyl Coenzyme A

Question 21

Reactants vs products of krebs cycle

Answer 21

2 Acetyle Coenzyme A

6 NADH
2 FAD
2 ATP
4 CO2

Question 22

Reactants vs products in ETC

Answer 22

NAD
FAD

34 ATP via oxidative phosphorylation

Question 23

SLP vs oxidative phosphorylation

Answer 23

SLP when ATP generated directly through respiration reactions (glycolysis and krebs)

Oxidative when ATP generated from chemical energy released when reduced hydrogen carrier or coenzyme had been oxidised at the ETC

Question 24

Glycolysis

Answer 24

Glucose phosphorylated using ATP hydrolysis

Glucose phosphate unstable so splits into 2 TP

TP oxidised into pyruvate using NAD reduction and ATP synthesis via SLP

Question 25

Link reaction

Answer 25

Pyruvate oxidised into acetate using reduction of NAD and produces carbon dioxide

Coenzyme A combines with acetate to form acetylcoenzyme A

Question 26

Krebs cycle

Answer 26

2 acetyl coenzyme A combined with 4C molecule to form 6C moleucle

6C loses carbon dioxide to become a 5C molecule using the reduction of NAD

5C converted to 4C using ATP synthesis, FAD and NAD reduction

Produces 4C which allows cycle to continue

Question 27

Explain oxidation in glycolysis and in krebs

Answer 27

Removal of hydrogen
By dehydrogenase
H accepted by NAD
Forms NADH
In krebs cycle, FADH formed too

Question 28

How is water formed at the end of ETC

Answer 28

Oxygen is the final electron acceptor

Combines with electrons and protons to form water