June 2023 Past Paper Component 1

Question 1

What is the general name for protein labelled C (1)

Answer 1

Proton pump

Question 2

Name the 2 organelles in structure D and where they would be located (2)

Answer 2

. Mitochondria + inner membrane
. Chloroplast + thylakoid membrane

Question 3

State if this reaction is endergonic or exergonic (1)

Answer 3

. Endergonic + energy being stored

Question 4

State one adaptation shown by tissue layer B and explain the function of this adaptation (2)

Answer 4

.Presence of air spaces enable diffusion of gases / storage of gases

. Chloroplast to absorb light that has passed through upper cells

Question 5

State 3 factor that are required for germination of seed (1)

Answer 5

. Water
. Oxygen
. Suitable temperature

Question 6

Explain why this method provides a more accurate estimate of the total leaf surface area than drawing around each leaf on a piece of graph paper (2)

Answer 6

. Leaves are irregular so difficult to draw around
. Leaves may not be flat so drawing around not representative of actual area
. Counting square can open to human error

Question 7

Give 2 ways in which the data from both trees show a normal distribution (2)

Answer 7

. Mode and mean in the same range
. The mean / bell shaped curve

Question 8

Conclude which tree are more likely to have been growing under the tree canopy. Use knowledge of tree adaptation to give 2 reason (3)

Answer 8

. Tree 1 is larger surface area
. More stomata
. More chloroplast

Question 9

Describe the difference between alpha and beta isomers of glucose (1)

Answer 9

. OH below C1 on alpha glucose and above on beta glucose

Question 10

Explain how the induced fit mechanism enables hexokinase to accept both isomers (2)

Answer 10

. Active site changes shape
. Alpha and beta glucose has similar structure

Question 11

Name the process by which ATP is produced directly in glycolysis (1)

Answer 11

Substrate level phosphorylation

Question 12

Explain why there is a net yield of 2 ATP produced directly in glycolysis (2)

Answer 12

. 2 ATP used to phosphorylate glucose to triose phosphate
. 4 ATP produced

Question 13

Identify one type of enzyme involved in the conversion of triose phosphate to pyruvate and state the function of this type of enzyme (2)

Answer 13

. Dehydrogenase
. Removal of hydrogen

Question 14

Explain how glucose 6 phosphate could inhibit hexokinase (3)

Answer 14

. Act as a competitive inhibitor
. 6GP has similar shape to glucose
. G6P can bind to active site
. G6P can slow conversion to glucose to G6P

Question 15

Use ur knowledge of the nitrogen cycle to explain the sequence of the appearance of ammonia and nitrite and nitrates (4)

Answer 15

. Ammonia produced by Decomposer
. NH4+ converted to NO2
. By nitrosomonas
. Nitrite to nitrate
. By nitrobacter

Question 16

Explain why the water was continually aerated (2)

Answer 16

. Aeration provide a source of O2
. Nitrifying bacteria are aerobic / nitrification only takes place in aerobic condition
. Prevent denitrification

Question 17

Suggest a possible explanation for the change in the nitrate concentration at day 45 (1)

Answer 17

. Some of water changed / tank cleaned

Question 18

Suggest what would happen to the concentration of nitrate ions if plants were grown in aquarium (2)

Answer 18

. Concentration decreases as plant absorb nitrate ions
. To synthesis proteins/ nucleic acid

Question 19

Suggest why the concentration of nitrogen containing compounds may increase if too many fish are introduced in aquarium (3)

Answer 19

. Egestion
. Contains N containing compounds
. N containing compounds released during decay of dead fish /feaces

Question 20

Suggest why fish died and explain your answer (3)

Answer 20

. Algal bloom
. Bacteria decomposes dead plants
. Use of oxygen from water
. Fish die as they cannot respire due to lack of oxygen

Question 21

Explain what is meant by facultative anaerobe (1)

Answer 21

. Can survive aerobically and anaerobically / can survive in aerobic and anaerobic condition

Question 22

Name the process by which these bacteria enter cell and explain why ATP is needed for this take place (2)

Answer 22

.Endocytosis
. ATP needed as a source of energy to change shape of cell

Question 23

Describe and explain 2 precautions that must be taken when inoculating an agar plate (2)

Answer 23

. Do not place lid of container on bench - to reduce risk of contamination
. Keep lid of petri dish at an angle - reduce the risk of contamination

Question 24

Math question MPN

Answer 24

1.19

Question 25

Explain why subsequent colonisation of these verges can be described as secondary succession (2)

Answer 25

. Soil is already present . Seed and roots already present

Question 26

Explain why cutting the vegetation is this way on a regular basis prevents succession reaching a climax community (1)

Answer 26

. Shrubs / tree seedling cut down so cannot grow to full size . No seral progression

Question 27

Conclude how this increase the biodiversity of wildflowers in motorways verges (3)

Answer 27

. Prevent vegetation being decayed on the verges . Decay products don’t enter the soil . Windflowers are adapted to live in low fertility soil

Question 28

Suggest one ethical and one ecological concern regarding the method (2)

Answer 28

. Insect are killed . Removing pollinators / reduces biodiversity

Question 29

Use all the information provided including the method used to collect the date to evaluate this conclusion (4)

Answer 29

. No data on how biodiversity changed over time / different biodiversity at different times of the year . Verges were close to agricultural land so insect could have came from field . Only 4 colours of trap used . Different crops in field could have affected biodiversity at different sites . Sample size too small

Question 30

9 marker

Answer 30

.Density dependent: increased effect as population increases/ (affect and) are affected by the size of the population .Density independent: the effect is the same whatever the population size /(affect but) not affected by the size of the population 1st para; {better/ more} food A4 lower levels of disease/ parasites A5 better shelter / housing A6 improved health care / sanitation/ better water supply 2nd para: X – population still in log phase/ exponential growth/ population doubling in unit time B2 birth (rate) greater than death (rate) / people {living/ surviving} longer B3 Y – reached {stationary (phase) / carrying capacity/ plateaus/ no further change} B4 B5 B6 birth /survival = death rate Z – {decline/ death} phase birth rate less than death rate/ people not living as long 3rd para; . decreased population .C2 reduces need for fossil fuel combustion so less CO2 emitted . C3 {less deforestation/ more afforestation/ or description of} {so more CO2 absorbed / can act as carbon sinks} .C4 fewer {animals farmed / paddy fields} so less methane . C5 get closer to safe operating level for climate change boundary/ effects of crossing the boundary are reduced