Paper 1 Mistakes

Question 1

Non-reducing sugar test

Answer 1

Do Benedict’s test and stays blue/negative

Boil with HCl and neutralise with sodium hydrogencarbonate

Heat with Benedict’s and becomes brick red precipitate

Question 2

Lipids test

Answer 2

Add ethanol then water, shake to mix it

White/milky emulsion shows it’s present

Question 3

Properties of water

Answer 3

Metabolite in condensation/hydrolysis/photosynthesis/respiration

Solvent to allow metabolic reactions to occur and substances to be transport3

High specific heat capacity so buffers changes in temperature

High latent heat of vaporisation so provides a cooling effect through evaporation

Cohesion between water molecules to:
-support columns of water in plants
-provide surface tension supporting small organisms

Question 4

Evaluation qs

Answer 4

-stats test?
-sample size/age/gender/ethnicity?
-difference/correlation? (strong/weak etc)
-length of time?
-quote values

Question 5

No large lipid droplets are visible with the optical microscope in the samples from suspension A.
Explain why.
(2 marks)

Answer 5

1. Emulsification;
2. (Cannot be seen) due to resolution (of optical microscope);

Question 6

2 ways of ensuring the index of diversity is representative?

Answer 6

Random samples

Large number of samples

Question 7

Pros and cons of farmers replanting hedges on their farmland

Answer 7

Advantage -
1. Greater (bio)diversity so increase in predators of pests
OR
Increase in predators of pests so more yield/income/less pesticides/less damage to crops
OR
Increase in pollinators so more yield/income
OR
May attract more tourists/subsidies to their farm so more income (from diversification);
Disadvantage -
2. Reduced land area for crop growth/income
OR
Greater (bio)diversity so increase pest
population
OR
Increase pest population so less yield/less income/(more) need for pesticides/(more) damage to crops
OR
Increased (interspecific) competition so less
yield/income
OR
More difficult to farm so less income;