Photosynthesis, Food Production and Management of the Environment | OCR A-Level Biology B (Advancing Biology) (H422)

Photosynthesis, Food Production and Management of the Environment

181 questions
12 subtopics
Biology content, examined on all three papers
Component 01, Component 02 and Component 03

Photosynthesis, Food Production and Management of the Environment is examined in all three written papers — the specification states that Components 01, 02 and 03 can each assess content from any of the five modules, so nothing is confined to one paper.

It covers chloroplast ultrastructure and photosynthetic pigments, the light-dependent stage of photosynthesis, the Calvin cycle, investigating the factors affecting photosynthesis, the Hill reaction and DCPIP, using TP and GP to build carbohydrates, lipids and amino acids, the compensation point and crop production, microorganisms, the nitrogen cycle and biosensors, biomass transfer and efficiency in food production, ruminants in the human food chain, farms as ecosystems and the conflict with conservation and deflected succession and measuring biodiversity.

Sample questions from Photosynthesis, Food Production and Management of the Environment

Answer each one closed book first, then open the answer.

Chloroplast ultrastructure and photosynthetic pigments

Explain the advantage of the thylakoid membranes being arranged in stacks.

Show the answer
Stacking packs a very large membrane surface area into a small volume, so many more light harvesting complexes and photosystems can be held for absorbing light.
The light-dependent stage of photosynthesis

What is the final electron acceptor of the light-dependent stage, and what is formed?

Show the answer
NADP is the final electron acceptor, and it combines with electrons and a proton to form reduced NADP.
Investigating the factors affecting photosynthesis

Describe how the effect of wavelength on photosynthesis is investigated.

Show the answer
Coloured filters that transmit known wavelengths are placed between a lamp of fixed intensity and the plant, and the rate of oxygen release is measured for each filter.
The Hill reaction and DCPIP

Why is a red filter chosen for the colorimeter in this investigation?

Show the answer
DCPIP is blue, so it absorbs red light most strongly and the change in absorbance as it is reduced is largest with a red filter.
The compensation point and crop production

On a graph of net carbon dioxide uptake against light intensity, what does the point where the line crosses the x-axis represent?

Show the answer
It is the compensation point, the light intensity at which net carbon dioxide uptake is zero.
Microorganisms, the nitrogen cycle and biosensors

How is the nitrogen in the proteins of dead organisms and wastes returned to the soil as ammonium ions?

Show the answer
Saprotrophic bacteria and fungi decompose the proteins and urea, releasing ammonium ions in the process called ammonification.
Ruminants in the human food chain

Explain the benefit to a cow of chewing the cud.

Show the answer
Further chewing breaks the plant material into smaller pieces, increasing the surface area available to microbial cellulase and so speeding up digestion.
Farms as ecosystems and the conflict with conservation

Why is slurry particularly damaging if it reaches a watercourse?

Show the answer
Slurry has a very high biochemical oxygen demand, so the bacteria decomposing it use up the dissolved oxygen and aquatic animals suffocate.

The 12 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Chloroplast ultrastructure and photosynthetic pigments	Recall questions on the chloroplast envelope, thylakoids, grana, stroma and intergranal lamellae, where the light-dependent components and RuBisCO sit, chloroplast DNA and ribosomes, and separating chlorophyll a, chlorophyll b, carotene and xanthophyll by paper chromatography with Rf values.	16
The light-dependent stage of photosynthesis	Recall questions on where the light-dependent stage happens, light harvesting complexes and photoactivation, the electron transport chain and proton gradient, photophosphorylation by ATP synthase, the photolysis of water, NADP as final electron acceptor, and the effects of darkness and herbicides.	14
The Calvin cycle	Recall questions on the site of the cycle, the fixation step and its enzyme, what the light-dependent stage supplies, turns per glucose, and the effect of sudden darkness.	15
Investigating the factors affecting photosynthesis	Recall questions on measuring oxygen release, why hydrogencarbonate is added, how lamp distance changes intensity, wavelength and temperature effects, and why readings wait after a change in conditions.	15
The Hill reaction and DCPIP	Recall questions on what isolated chloroplasts demonstrated, the dye's colour change, why the extraction medium is ice-cold, isotonic and buffered, and the controls a valid experiment needs.	13
Using TP and GP to build carbohydrates, lipids and amino acids	Recall questions on turning triose phosphate into hexose, starch, sucrose, cellulose and triglycerides, building amino acids from GP with nitrate and sulfate, nitrate deficiency, and why plant respiration and animal nutrition both depend on photosynthesis.	14
The compensation point and crop production	Recall questions on the compensation point and compensation period, shade and sun plants, reading net carbon dioxide uptake graphs, crop spacing and glasshouse lighting, and using hydrogencarbonate indicator, with controls and a water bath, to compare compensation points.	15
Microorganisms, the nitrogen cycle and biosensors	Recall questions on nitrogen fixation by Azotobacter and Rhizobium, nitrogenase and leghaemoglobin, nitrification by Nitrosomonas and Nitrobacter, ammonification, legumes in crop rotation, culturing Rhizobium aseptically from root nodules, and luminescent bacteria as biosensors of water toxicity.	17
Biomass transfer and efficiency in food production	Recall questions on biomass and dry mass, calculating the efficiency of biomass transfer, why biomass is lost between trophic levels, the length of food chains, farmed fish compared with beef cattle, the sustainability of salmon farming, feeding maize to cattle, and rearing livestock indoors.	14
Ruminants in the human food chain	Recall questions on the rumen, reticulum, omasum and abomasum, rumination and chewing the cud, how rumen microorganisms digest cellulose and supply volatile fatty acids and protein, the carbon dioxide and methane they produce, the mutualism, and the value and environmental cost of ruminants as food.	14
Farms as ecosystems and the conflict with conservation	Recall questions on the biotic and abiotic factors a farmer manages, why a monoculture is unstable, intensive and extensive farming, hedgerow removal, eutrophication from nitrate, persistent pesticides, slurry and safe disposal of farm waste, and the Countryside Stewardship scheme.	16
Deflected succession and measuring biodiversity	Recall questions on succession, pioneer species and climax communities, primary and secondary succession, deflected succession and the plagioclimax maintained by grazing, forestry and ploughing, and sampling with random quadrats and line or belt transects, frequency, percentage cover and species-area curves.	18

Photosynthesis, Food Production and Management of the Environment is 181 of the 2,895 questions in the guide.Get the guide, £8

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.