2020 Biology Mistakes

Question 1

What is magnesium ions responsible for making

Answer 1

Chlorophyll

Question 2

Describe effects of eroding of liver

Answer 2

No bile made (in the liver)
fats / lipids are not emulsified
surface area of fats / lipids not increased pHofsmallintestinewillnotbealkaline/neutralised enzymes (in small intestine) will not work effectively or (named) food not digested / absorbed somayloseweight
• lactic acid not broken down / oxidised
o accumulation of lactic acid in blood / body o lactic acid is toxic or body will be poisoned o oxygendebthigher/prolonged
o so muscle pain / fatigue
• proteins / amino acids will not be broken down (in liver) o (amino acids) not deaminated
o amino acids not made into urea or will not form ammonia
o (however)anyammoniaformedistoxic
o so accumulation of amino acids in blood / body
• liver does not break down / remove other toxins (like alcohol) o toxins accumulate in blood / body
- bodywillbepoisoned
- so pain or jaundice or swollen liver or portal hypertension occurs
• glycogen stores will not be formed cannotcontrolbloodglucose
so hyperglycaemia / hypoglycaemia / diabetes / coma may occu

Question 3

How many μm in a mm

Answer 3

1 μm = 0.001 mm
or 1 mm = 1000 μm

Question 4

Adaptation of lungs for gas exchange

Answer 4

• provide a large(r) surface area (: volume)
• capillaries are thin
or alveoli / capillary walls are thin or one cell thick or capillaries are close to the alveoli
• which provides short diffusion path (for oxygen / carbon dioxide)
• breathing (mechanism) moves air in and out or lungs are ventilated
• to bring in (fresh) oxygen
• to remove carbon dioxide
• to maintain a concentration / diffusion gradient
• large capillary network (around alveoli) or good blood supply
• to remove oxygen(ated blood) quickly
• to bring carbon dioxide to the lungs quickly
• to maintain a concentration / diffusion gradient

Question 5

Describe the 3 stages of cell division (mitosis)

Answer 5

stage 1)
DNA / chromosomes replicate / duplicate
mitochondria / ribosomes / sub- cellular structures increase in number
or mitochondria / ribosomes / sub-cellular structures replicate
(stage 2)
one set of chromosomes is pulled / moved to each end of the cell
(stage 3)
the cytoplasm and cell membrane divides (to form two cells)

Question 6

Describe lock and key method

Answer 6

enzyme binds to the substrate because they are complementary (shapes)
(so) substrate is broken down (into products)
(so) products are released

Question 7

How to change investigation of testing plants for glucose and starch

Answer 7

test roots / stems of plants (in
the light and dark)

Question 8

Describe clinical test of drug trials

Answer 8

given first to healthy volunteers o at(very)lowdose
o totestitissafeortotestfortoxicityortocheckfor any side effects
• then to some patients (with the disease) or people with the disease
o totestforthecorrect/optimumdose o to check for any side effects
o totestforefficacyortotestifitworks o in a double blind trial
o where neither patients nor doctors know who has the mAbs and who has a placebo (or alternative treatment)