Question 1:-
Read the passage below. Use the information in the passage and your own
knowledge to answer the questions that follow.
When the Oceans Glow
5 In some areas of the wo rld the oceans around the coast sometimes glow with a blue light. The photograph shows an area of coast that is glowing. This blue light is produced by the presence of thousands of microscopic, living organisms called dinoflagellates. These dinoflagellates are protoctists. The production of light by living organisms is called bioluminescence, a process that has evolved many times in different species of organism.
10 To generate light, dinoflagellates use special proteins and the ATP produced within their cells. Many species of dinoflagellate contain chlorophyll and are able to photosynthesize. The appearance of glowing dinoflagellates in the sea used to be a rare event but this now occurs much more frequently. Many of the events occur in the sea around river estuaries and scientists think that intensive farming and deforestation could be to blame. Due to overpopulation of dinoflagellates in these areas, other species of animal are often harmed. After a series of glowing events, large numbers of dinoflagellates die causing oxygen levels in the water to decrease.
15 People have often wondered why dinoflagellates glow. They only glow in areas where the water moves around, such as when waves hit a beach. Scientists now think that the production of light is a type of warning to stop predators eating the dinoflagellates. If an animal eats dinoflagellates, the dinoflagellates in the area glow making the animal obvious to its own
predators. To test this, scientists placed dinoflagellates into a tank along with 15 copepods, which are predators of dinoflagellates. When the dinoflagellates glowed, the copepods ate 20 1200 dinoflagellates in two hours. When the dinoflagellates did not glow, the copepods ate 2100 dinoflagellates in two hours.
25 Some scientists think that we could make use of the dinoflagellates to provide sustainable street lighting. Tanks of dinoflagellates could be placed on top of lamp posts. The dinoflagellates would photosynthesise during the day when it is light. A stirrer powered by a small battery would then move them at night so that they would glow. These sustainable lamps could be carbon neutral and help to reduce pollution.
(a) Which of these processes produces ATP? (line 6)
A active transport
B diffusion
C respiration
D transpiration
(b) (i) Explain why intensive farming and deforestation would cause an increase in populations of dinoflagellates. (lines 9 to 11)
(ii) Explain why oxygen levels decrease after a series of glowing events. (lines 10 to 13)
(c) Which type of bacteria converts ammonia into nitrates?
A decomposer
B denitrifying
C nitrifying
D nitrogen fixing
(d) (i) Each of the 15 copepods ate glowing dinoflagellates at a mean rate of 40 dinoflagellates per hour.
Calculate the mean rate at which each copepod ate dinoflagellates that were not glowing. (lines 18 to 21)
mean rate = …………………………………………………….. dinoflagellates per hour
(ii) Explain how natural selection could have resulted in the evolution of dinoflagellates that glow. (lines 15 to 18)
(e) Explain why using dinoflagellates for street lighting would help to reduce pollution. (lines 22 to 26)
▶️Answer/Explanation
Ans : 1(a) The only correct answer is C (respiration)
A is incorrect as active transport does not produce ATP
B is incorrect as diffusion does not produce ATP
D is incorrect as transpiration does not produce ATP
1(b)(i) An explanation that makes reference to three of the following.
• soil erosion / soil erodes (1)
• fertiliser / organic material (1)
• run off / leaching / washed in / eq (1)
• (increased) magnesium / nitrates / phosphate / minerals (1)
• for correct matched function e.g. magnesium for chlorophyll production / nitrates for amino acids / nitrates for proteins (1)
• (more) carbon dioxide for photosynthesis (1)
Allow roots do not hold soil together
Allow other correct minerals
Ignore nutrients Functions must be matched to minerals
Ignore growth / repair
1(b)(ii) An explanation that makes reference to two of the following.
• decomposition / decay / respiration / eq (1)
• (by) bacteria / fungi / microorganisms / microbes (1)
• less photosynthesis (1)
Ignore rot Ignore breakdown
Ignore viruses
1(c) The only correct answer is C (nitrifying)
A is incorrect as decomposers do not release nitrates
B is incorrect as denitrifying bacteria do not release nitrates
D is incorrect as nitrogen fixing bacteria do not convert ammonium to nitrates
1(d)(i) 70 (2)
One mark for ÷ 15 or ÷2 or ÷ 30 or 1050 or 140
Correct answer gains all marks
1(d)(ii) An explanation that makes reference to four of the following.
• mutation (produced glowing dinoflagellates) (1)
• (produces) variation (1)
• (glowing dinoflagellates) survive / not eaten / eq (1)
• reproduce / make offspring / eq (1)
• pass allele / gene (for glowing on to offspring) (1)
Allow converse for non glowing throughout
pass allele gene onto offspring = 2 marks
1(e) An answer that makes reference to three of the following.
• photosynthesis (1)
• takes in carbon dioxide / less carbon dioxide in atmosphere / less carbon dioxide released / eq (1)
• less / no use of electricity / eq (1)
• less fossil fuel use / oil / coal / gas / eq (1)
• less (enhanced) greenhouse effect / global warming (1)
• less sulfur dioxide / less acid rain (1)
Ignore carbon neutral (in text) Allow will reduce carbon dioxide / less carbon emissions
Allow less greenhouse gas
Question 2:-
A student uses this method to investigate water uptake and water loss by a plant shoot.
• pour 100cm3 of water into a measuring cylinder
• place a plant shoot into the measuring cylinder
• cover the surface of the water with oil
• place the measuring cylinder and plant shoot on a balance and record the total mass
• shine light on the plant shoot using a lamp
• record the volume of the water in the measuring cylinder after four days, and after eight days
• record the total mass of the measuring cylinder and plant shoot after four days, and after eight days
The diagram shows the student’s apparatus.
(a) State the reason for using the oil.
(b) The table shows the student’s results.
(i) The volume of water taken up by the plant shoot is equal to the change in volume of water in the measuring cylinder. This is called the water uptake.
Calculate, in cm3 per day, the mean rate of water uptake by the plant shoot during the eight days.
mean rate = …………………………………………………….. cm3 per day
(ii) Comment on the changes in total mass of the measuring cylinder and plant shoot, compared with the changes in volume of water in the measuring cylinder.
[1cm3 of water has a mass of 1g]
(c) Explain why the rate of water loss would be different if a working fan is placed in front of the plant shoot.
▶️Answer/Explanation
Ans : 2(a) An answer that makes reference to the following.
• prevent evaporation (from surface of water) / eq (1)
Allow ensure water loss is from plant / eq Ignore stops water loss unqualified
2(b)(i) • 4.4 or 4.38 or 4.375 (2)
Allow 4.37
One mark 35 or ÷ 8
Ignore 4.3 but credit any correct working
Correct answer gains all marks
2(b)(ii) An answer that makes reference to four of the following.
• both / volume and mass, decrease / eq (1)
• volume changes more than mass / more water is taken up than lost (up to 4 or 8 days) / eq (1)
• water loss and uptake are same between 4 and 8 days / after 4 days / eq (1)
• correct numerical manipulation (1)
• transpiration occurs / water evaporates (from leaves) / water lost through stomata (1)
• (some) water is retained / stored in cells / (used for) turgor (1)
• used in photosynthesis (1)
Need not be stated in same sentence
Allow volume decreases more than mass = 2 marks
e.g. 35 (cm3) lost / 10 (g) lost after 4 days Ignore quoting data
2(c) An explanation that makes reference to three of the following.
• more transpiration / more evaporation / higher (water loss) / faster (water loss) / eq (1)
• (wind) blows /moves, the water away / removes still air / removes humid air / eq (1)
• increases / maintains / steeper diffusion gradient / concentration gradient / eq (1)
Allow converse for all mark points
Allow more water (moves) into air
Allow keeps air dry
Allow water potential gradient
Allow maintains a difference in concentration
Question 3:-
The diagram shows part of a human nephron.
(a) Which structure is the proximal convoluted tubule?
A
B
C
D
(b) The hollow space inside a blood vessel is called the lumen.
(i) The blood vessel labelled X has a lumen with a radius of 100 μm.
Use this formula to calculate the cross‐sectional area, inmm2 , of the lumen of this blood vessel.
area of circle = π×(radius)2
[π = 3.14]
[1mm = 1000μm]
cross‐sectional area = …………………………………………………….. mm2
(ii) The lumen of blood vessel X is wider than the lumen of blood vessel Y.
Explain why this difference in the width of the lumen of the two blood vessels is important for kidney function.
(c) Protein is often found in the urine of people who have high blood pressure.
Describe how urine could be tested for protein.
▶️Answer/Explanation
Ans : 3(a) The only correct answer is A (proximal convoluted tubule)
B is incorrect as it is the distal convoluted tubule
C is incorrect as it is the collecting duct
D is incorrect as it is the loop of Henle
3(b)(i) 0.03 (2)
Allow 0.031 or 0.0314 or other correct significant figures
Allow 3.14 x 10-2 , 3 x 10-2
One mark for 0.1 or 100/1000 or 31400
Correct answer gains all marks
3(b)(ii) An explanation that makes reference to two of the following.
• increases the pressure / creates high pressure / eq (1)
• (for) ultrafiltration (1)
• so that plasma / small molecules / fluid / filtrate, leave glomerulus / enter Bowman’s capsule / eq (1)
Allow generates pressure
Allow renal capsule
Allow correct named small molecule e.g. urea
Allow small particles Ignore blood
3(c) A description that makes reference to the following.
• biuret (reagent) (1)
• lilac / purple / pink / mauve / eq (1)
Allow ninhydrin Allow uristix / clinistix
Allow ninhydrin goes pink / red Allow uristix / clinistix go brown / green
Question 4:-
(a) The diagram shows a cross‐section through part of a plant leaf.
(i) What is the name of the cell labelled P?
A cuticle
B guard
C palisade
D stoma
(ii) Explain how part Q is adapted for photosynthesis in the leaf.
(b) A student uses this method to investigate the effect of temperature on the rate of gas exchange in leaves.
• pour 10cm3 of hydrogen‐carbonate indicator into each of six test tubes
• hang a leaf in five of the test tubes
• place a bung in each test tube
• place the five tubes with leaves into separate water baths at temperatures of 15°C, 20°C, 25°C, 30°C, 35°C, and 40°C
• place the tube with no leaf in a water bath at 25°C
• place all tubes in bright sunlight
• record the time taken for each of the hydrogen‐carbonate indicator solutions to change from orange to red
The student repeats the experiment two more times.
The diagram shows one of the tubes with a leaf.
(i) State the independent variable.
(ii) The species and size of leaf were the same in each tube.
Give a reason for controlling one other named factor.
factor
reason
(iii) State the function of the tube with no leaf.
(c) The table shows the student’s results.
(i) Calculate the mean time taken for the indicator to change from orange to red at 25°C.
Give your answer to two significant figures.
mean time = …………………………………………………….. minutes
(ii) Explain the effect of increasing the temperature on the mean time taken for the indicator to change from orange to red.
(d) In another experiment, the student places a test tube containing a leaf and hydrogen‐carbonate indicator in a 25°C water bath.
The student then places all this apparatus in the dark for one hour.
Explain why the indicator solution changes from orange to yellow.
▶️Answer/Explanation
Ans :
4(a)(i) The only correct answer is B (guard)
A is incorrect as it is the cuticle
C is incorrect as it is a palisade cell
D is incorrect as it is a stoma
4(a)(ii) An explanation that makes reference to three of the following.
• spongy mesophyll / spongy cells / spongy tissue / spongy layer (1)
• has air spaces / gaps between cells / spaces / eq (1)
• (for) diffusion / gas exchange (1)
• carbon dioxide moves in (to palisade cells) / oxygen out (from palisade cells) / eq (1)
• xylem to transport water (1)
Ignore chloroplasts / chlorophyll
Reject palisade
Allow pockets (of air)
Ignore phloem
4(b)(i) An answer that makes reference to the following.
• temperature (of water bath) (1)
Ignore heat
4(b)(ii) An answer that makes reference to two of the following.
• light (1)
• changes stomatal opening / (affects) photosynthesis / eq (1)
OR
• volume / concentration of (hydrogen carbonate) indicator (1)
• different volumes / concentrations would release / absorb different amounts of carbon dioxide /eq (1)
OR
• size of tube (1)
• would affect concentration of carbon dioxide / eq (1)
OR
• pH (1)
• affects enzymes / photosynthesis / eq (1)
OR
• age of leaf (1)
• may affect chloroplast number / amount of photosynthesis / eq (1)
OR
• starting concentration of carbon dioxide (1)
• (carbon dioxide) is needed for photosynthesis/ is a limiting factor (1)
max one for factors
Mark in pairs reason can only be awarded if factor is correct except for carbon dioxide
Allow to prevent light being a limiting factor
Ignore amount of indicator
Allow different volumes would affect time to change colour / different volumes would result in different colour change / eq
Allow for this one case only correct reason if just says carbon dioxide as factor
4(b)(iii) An answer that makes reference to the following.
• control (experiment) / to compare / show effect of temperature on indicator / show that leaf is required to affect the colour / eq (1)
Ignore control variable
Allow shows changes are due to leaf / photosynthesis
4(c)(i) • 27 (2)
One mark for 26.7 or 26.67 or 26.667 or 26.6667 or 26.66667 or other correct decimal places or 26.6 recurring or 27.0
Ignore 26.6
Answer on answer line takes precedence over answer in table
Correct answer gains all mark
4(c)(ii) An explanation that makes reference to three of the following.
• faster photosynthesis / eq (1)
• (more) carbon dioxide is removed / taken in / absorbed / eq (1)
• increased collisions / more (kinetic) energy / faster movement of molecules / eq (1)
• (levels off as) another factor limits / light intensity limits the rate / temp no longer limiting / eq (1)
Ignore references to respiration
Allow less carbon dioxide (in solution / tube)
Allow more E/S complexes / optimum temperature for enzymes
4(d) An explanation that makes reference to two of the following.
• respiration is faster than photosynthesis / more respiration than photosynthesis / eq (1)
• so carbon dioxide is released / increases (in indicator / tube) / eq (1)
Allow respiration but no photosynthesis
Reject if candidate suggests that respiration ONLY starts after photosynthesis stops e.g.
respires instead of photosynthesising
Question 5:-
Hormones control the menstrual cycle.
(a) (i) Name the gland that produces FSH.
(ii) The diagram shows the changes in four hormones during the human menstrual cycle.
Which line represents the hormone progesterone?
A
B
C
D
(iii) Describe the roles of FSH and LH in the menstrual cycle.
FSH
LH
(b) Reproductive hormones can be used as contraceptives to prevent pregnancy.
The table gives information about three different methods of hormonal contraception.
Discuss the advantages and disadvantages of the three methods of contraception shown in the table.
▶️Answer/Explanation
Ans :
5(a)(i) pituitary (gland) (1)
Ignore anterior or posterior
5(a)(ii) The only correct answer is D
A is incorrect as it is oestrogen
B is incorrect as it is LH
C is incorrect as it is FSH
5(a)(iii) A description that makes reference to the following.
• (FSH) matures eggs / follicles / eq (1)
• (FSH) stimulates oestrogen (release) / eq (1)
• (LH) induces ovulation / egg release / eq (1)
• (LH) stimulates progesterone / oestrogen (release) / stimulates corpus luteum (development) / eq (1)
Allow grows / develops Allow oocytes
Allow FSH makes (ovary / follicle) release oestrogen Allow estrogen / estradiol
Allow oocyte
Allow (LH) makes (ovary / corpus luteum) release progesterone / oestrogen Allow yellow body
5(b) An answer that makes reference to five of the following.
Overall comments
1. tablets are less effective / tablets have a wider range of effectiveness / implants or injections are more effective / eq (1)
2. no protection against HIV / (any method) may cause side effects / eq (1)
Tablets
3. max one advantage from:
• tablets are easy to use / no need for medical treatment / no need for doctor / surgery / good if people scared of needles / not painful / eq (1)
• easy to stop if, change mind / want to have children / quick to restart cycle (1)
4. max one disadvantage from:
• tablets easy to forget / need to take every day / eq (1)
• tablets may not be effective if vomiting / may be affected by food / eq (1)
Injection
5. max one advantage from:
• injections last long time / don’t need to keep going to doctor / eq (1)
• can’t forget to take / don’t need to take every day / no need to keep remembering (1)
6. max one disadvantage from:
• need to be given by doctor / health professional / eq (1)
• can be painful /some people are scared of needles / eq (1)
• longer for cycle to return / difficult to change mind / eq (1)
Implant
7. max one advantage from:
• implant last long(est) time / don’t need to keep going to doctor / eq (1)
• can’t be forgotten / no need to keep remembering / don’t need to take every day (1)
• good for people who have less access to doctors (as it lasts for 3 years) / eq (1)
8. max one disadvantage from:
• need to be given by doctor / health professional / eq (1)
• could cause infection / damage tissues / leave scars / painful / eq (1)
• implant could produce very high hormone levels / eq (1)
• not easy to change mind / will take longer to return to normal with implant / eq (1)
Allow mp2 for any method Allow STI / other STIs/ named side effects
Allow tablets easy to obtain / may be obtained from pharmacist
Ignore injection lasts 12 weeks unqualified
Ignore implant last 3 years unqualified Injection and implant are long lasting = two marks
Question 6:-
The photograph shows a plant called a snapdragon.
Selective breeding has been used to produce snapdragons with brightly coloured flowers.
(a) (i) Describe how selective breeding can produce snapdragon plants with brightly coloured flowers.
(ii) Micropropagation is often used to make copies of a snapdragon plant. Describe the process of micropropagation.
(b) Scientists investigate the effect of exposing snapdragon explants to increasing amounts of ionising radiation.
This is the scientists’ method.
• take a snapdragon plant and use micropropagation to produce many explants
• expose groups of explants to different amounts of ionising radiation
• grow the explants into plants and record the number of differences in their phenotypes compared with the original plant
• take samples of each of the plants and measure the number of differences in DNA nucleotides of each plant compared with the original plant
(i) Give the reason why micropropagation is used to produce the plants to be tested.
(ii) What term is given to all the DNA in an organism?
A gene
B genome
C genotype
D nucleoid
(iii) The graph shows the scientists’ results.
Discuss the effects that increasing the amount of ionising radiation has on the snapdragons.
▶️Answer/Explanation
Ans : 6(a)(i) A description that makes reference to the following.
• select plants with bright flowers and pollinate / breed / cross / eq (1)
• select offspring (with bright flowers) and pollinate / breed / cross / repeat with offspring / eq (1)
Allow desired characteristics Allow breed two plants with bright flowers
Allow repeat over several generations if mp1 has been awarded
Ignore repeat if not about offspring / next generations
6(a)(ii) A description that makes reference to three of the following.
• take small samples / small tissue / few cells / scrape cells off / remove growth tips / eq (1)
• sterilise / wash with ethanol / alcohol / disinfectant / antiseptic / eq (1)
• (place into) agar (1)
• provide minerals / glucose / carbohydrates / amino acids / eq (1)
• plant growth substances / auxin / rooting powder (1)
Allow any idea of small pieces of plant e.g. fragment Allow meristems
Sterile agar = 2 marks Allowbleach
Allow agarose
Ignore nutrient Allow named minerals Allow sugar
Allow hormones
6(b)(i) An answer that makes reference to the following.
• all plants will be genetically identical / have same DNA / same genetic material / same genes / same alleles / eq (1)
Allow so they will be clones
6(b)(ii) The only correct answer is B (genome)
A is incorrect as all the DNA is not a gene
C is incorrect as all the DNA is not a genotype
D is incorrect as all the DNA is not a nucleoid
6(b)(iii) An answer that makes reference to four of the following.
• more radiation increases the number of changes in DNA / genotypes and number of different phenotypes / eq (1)
• mutations (have occurred in the DNA) (1)
• (mutations) change amino acid sequences / different protein / different enzyme / eq (1)
• changes in DNA increases more / steeper (than number of different phenotypes) / changes in DNA occur with lower amount (of
radiation) / eq (1)
• (some) DNA changes / mutations, have no effect / are silent / code for same amino acid / have similar amino acid / enzymes still work / proteins still work / eq (1)
• DNA changes / mutations, may be recessive (so do not affect phenotype) / eq (1)
Allow increase number of mutations and number of phenotypes Allow positive correlation between DNA changes and phenotypes
Ignore more rapid increase
Allow converse
Allow some mutations do not affect phenotype Allow mutations occur in non- coding DNA
