June 2021 Component 1 Past Paper

Question 1

State the precise location of photosystem in plants (1)

Answer 1

Found in grana / thylakoid membrane

Question 2

Explain how the arrangement of pigments in photosystem harvest light energy (3)

Answer 2

. Groups of diffrent pigments which absorb light at different wavelengths
. Chlorophyll a in reaction centre
. PS1 and PS2
. Chlorophyll at centre absorbs slightly different wavelengths

Question 3

Describe a method by which the pigment is concentrated on the origin line (1)

Answer 3

Spot extract, evaporate /dry, repeat

Question 4

State one variable which would need to be controlled if this method was used to compare the pigment in leaves of 2 diffrent species of plant (1)

Answer 4

Same solvent
Same chromatography paper

Question 5

Describe how you can confirm that your identification of pigment x using the Rf value was correct (2)

Answer 5

. Spot each pigment
. Compare position with orginal sample

Question 6

Suggest why cold water was placed between the light source between the light source and plant chamber (1)

Answer 6

Prevent increase in temperature in plant chamber

Question 7

Explain why it is important that the same 10 plants were used in all test (1)

Answer 7

.Diffrent plants will have diffrent mass/ surface area
. Different plants have different number of chloroplast

Question 8

Suggest a suitable control for this experiment (1)

Answer 8

. Repeat with same apparatus and condition
. No plant

Question 9

Describe how the experiment could be modified to determine the mass of a Co2 released by respiration (1)

Answer 9

Repeat but in dark

Question 10

Describe and explain how the temperature at which tomato plants are grown affects the sugar content of the tomato (4 marks)

Answer 10

. Photosynthesis increases slightly from 15-30
. More sugar produced
. 30C and above less sugar produced
. Greater increase in rate of respiration 15-40
. More sugar broken down as temp increases

Question 11

At high wind speed stomata close . Example one advantage and disadvantage of this response to the plant (2)

Answer 11

. Less water loss = A
. Carbon dioxide cannot diffuse into leaf = B

Question 12

Use ur knowledge of protein synthesis explain and why the sweetness of the tomatoes will not increase after they have been stored at low temperatures (2)

Answer 12

. mRNA not produced / no transcription
. Translation doesn’t take place
. Enzyme not produced

Question 13

State the meaning of the word fixed as used in the context (1)

Answer 13

Conversion into a form which can be used by living organism

Question 14

Name the nitrifying bacteria and describe how they produce a source of electrons and proton (3)

Answer 14

. Nitrosomonas + nitrobacter
. Ammonium ion to nitrates
. Nitrite to nitrates

Question 15

State the name given to this series of molecules (1)

Answer 15

Electron transport chain

Question 16

Describe how the energy released from the movement of these electron is used (3)

Answer 16

. Pumping proton
. Against concentration gradient
. From cytoplasm into cell wall
. Creating a proton gradient

Question 17

Describe how ADP is phosphorylated as a result of the reaction (3)

Answer 17

. Proton flow down concentration gradient
. Through stalked particle
. Provide energy to join ADP and pi

Question 18

Suggest how bacteria use the products of the reaction shown in bold (3)

Answer 18

. GP reduced to TP by NADH2
. Using energy from ATP
. ATP donates a P group to regenerate RUBP
. carbon fixation

Question 19

Evaluate the conclusion that hedge are the main reason for the decline in wading birds (2)

Answer 19

. All species decline in presence of hedgehog
. Not the only cause as Dublin and snipe also declined in absence of hedgehog

Question 20

Explain one advantage of expressing the change in number of breeding pairs (2)

Answer 20

. Advantage = can compare different starting number
. Disadvantages = if number are small then any change results in a large % change

Question 21

State 2 factors which could have allowed a very large population of hedgehogs (2)

Answer 21

. No natural predators
. Abundance of food / no intraspecific competion
. Less traffic

Question 22

State why it was necessary to carry out such a study before a decision was made to control the number of hedgehogs (2)

Answer 22

. To confirm that hedgehogs were not responsible for the decline
. To assess impact of other predators

Question 23

Suggest one ecological problems for each control measure for trapping and moving hedgehogs to mainland (1)

Answer 23

May cause a problem in area into which introduced / spread of disease

Question 24

Remove hedgehogs from wander breeding areas then ercect 1 metre high hedgehog proof fencing around the area (1)

Answer 24

Prevent natural movement of other species

Question 25

Trapping of hedgehogs followed by humane killing (1)

Answer 25

Wrong to kill animals when species already in decline

Question 26

Explain how cyanide would prevent the process of aerobic respiration (4)

Answer 26

. ATP synthesis via electron transport chain stop . Because cyanide stops transfer of an electron to final electron acceptor . Elected cannot be accepted by electron carrier . Flow of electron stops . Electron donors NADH2 and FADH2 cannot be oxidised

Question 27

Explain why blood lactate concentration rises as a symptom of cyanide poisoning (3)

Answer 27

. NADH cannot pass H to Krebs . H is given to pyruvate to make lactate . So that NAD regenerated . So glycolysis can continue to make ATP anaerobically

Question 28

Calculate how many apples seed (3)

Answer 28

2315

Question 29

Exaplin what is meant by climax community and why re growth of kelp forest is an example of secondary succession (2)

Answer 29

. The final stage of succession in which the species remains relatively stable . Repopulation / recolonisation of an area that has been previously colonised

Question 30

Suggest how the presence of sea otters in a habitat maintains biodiversity (4)

Answer 30

. Sea otters eat sea urchin so keep forest regrows . Wider range of ecological . Because sea otters eat a range of food no single species dominated the habitats . As a result the prey population decreases . Predators eats more of a diffrent species

Question 31

Explain why scientist consider that the destruction of sea otters population could contribute to an increase in global warming (3)

Answer 31

. As sea otters number decline sea urchin are not eaten so less kelp . Less photosynthesis . Less c02 removed from environment . Carbon dioxide is a greenhouse gas

Question 32

Exaplin why an increase in global warming could have been a contributing factor in the planetary boundary being crossed (2)

Answer 32

. Sea temperature increases . To above what suitable for organism Or . Ice caps melt . Causing destruction of habitat

Question 33

Describe 2 conservation measure which may have aided the recovery of sea otters population (2)

Answer 33

Protected areas Breeding programmes Legalisation to prevent hunting

Question 34

9 marker