2018 Paper 2

Question 1

Explain why more water is lost by breathing during a race

Answer 1

During the race, more energy was needed for muscle contraction. Therefore more aerobic respiration which uses oxygen so faster breathing fate required to take in more oxygen

Question 2

Plan an investigation to test light intensity in a specific area

Answer 2

Identify two areas - one light and one dark. At each area, divide area into coordinates. Use random number generator to generate 20 coordinates for each place, at each of these, place a 1m^2 quadrant and count number of dandelions. Measure light intensity at each quadrant. Record these and compare data at different light intensities

Question 3

How many chromosomes are there at the end of mitosis and meiosis

Answer 3

Mitosis - 46
Meiosis - 23

Question 4

Explain why sexual reproduction is an advantage

Answer 4

Sexual reproduction results in genetic variation in offspring so more individuals better adapted to survive. Seeds of a plant may disperse long distances allowing colonisation of new areas

Question 5

Purpose of damp blotting paper in seed experiment

Answer 5

Prevent water affecting direction of rot growth

Question 6

What can be drawn to show biomass

Answer 6

A pyramid on graph paper. Draw so it’s half way on axis

Question 7

Give a way biomass is lost

Answer 7

Through respiration

Question 8

Explain how fish died when untreated sewage containing organic matter and bacteria entered the river

Answer 8

Bacteria decay organic matter by digestion. They respire areobically, lowering oxygen concentration in river. Fish have less oxygen and die as less respiration occurs

Question 9

Explain how a change in amino acid in enzyme stops enzyme from working

Answer 9

Mutation changes base of dna. This changed the amino acid code for the sequence and so changes the protein formed. Enzymes is no longer complementary to substrate

Question 10

Describe how scientists could breed cows to produce cows with large volumes of low fat milk

Answer 10

Find the female with highest yeild and lowest fat and the male who’s offspring have the same characteristics. Cross these individuals. Select the best offspring for both characteristics from each generation and relay for several generations

Question 11

Describe how animals have evolved

Answer 11

Different population became isolated from each other. There was variation in the habitats. Mutation occurred. Better adapted to survive and pass on favourable characteristics and eventually cannot produce fertile offspring with the other population

Question 12

Why is blood test better to use to test for glucose levels than urine

Answer 12

Blood test gives results for current - blood test happens hours after