Sustainable fisheries & Role of biotechnology (both biology only)

Lesson 7.13 · AQA 8461

Sustainable Fisheries & Role of Biotechnology

Spec 4.7.5.3, 4.7.5.4 · Paper 2 · ~10 min

Biology only

🌿 Final lesson of Module 7

What you'll be able to do

By the end of this lesson, you'll be able to:

Objective 1 4.7.5.3

Explain how net size and fishing quotas conserve fish stocks at a sustainable level.

Objective 2 4.7.5.4

Describe the production of mycoprotein using Fusarium, including the spec-strict process language.

Objective 3 4.7.5.4 / 4.6.2.4

Evaluate GM crops and GM bacteria as biotechnology solutions, using mark-scheme-credit-worthy disadvantages.

Why sustainable fisheries matter

Spec wording

"Fish stocks in the oceans are declining. It is important to maintain fish stocks at a level where breeding continues, or certain species may disappear altogether in some areas."

Overfishing — catching fish faster than they can reproduce — has reduced many wild stocks. The key biological idea: if fish are caught before they reach breeding age, the population can't replace itself, and eventually collapses.

Definition

Sustainable fisheries = fishing practices that maintain fish stocks at a level where breeding continues, preventing population collapse.

Two spec-named methods

Spec wording

"Control of net size and the introduction of fishing quotas play important roles in conservation of fish stocks at a sustainable level."

MethodHow it conserves stocks

Control of net sizeLarger mesh holes allow young fish to escape the net. They survive to reach breeding age and reproduce, maintaining the population.

Fishing quotasLimits the number of fish that can be caught (often per species, area, or season). Ensures enough adults remain to breed and replace what is caught.

Biotechnology — the spec framing

Spec wording

Students should describe and explain biotechnical and agricultural solutions, including genetic modification, to the demands of the growing human population. Modern biotechnology techniques enable large quantities of microorganisms to be cultured for food.

The spec names three biotechnology applications. Learn all three by name:

1Mycoprotein Protein-rich food from the fungus Fusarium. Suitable for vegetarians.

2Human insulin Produced by GM bacteria. Used to treat people with diabetes.

3GM crops More food OR improved nutritional value (e.g. golden rice).

Application 1 — Mycoprotein

Spec wording (memorise verbatim)

"The fungus Fusarium is useful for producing mycoprotein, a protein-rich food suitable for vegetarians. The fungus is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified."

Mark scheme strictness

AQA mark schemes are precise on mycoprotein: name the genus Fusarium (not "mushroom" or "fungus" alone); name glucose syrup (not "sugar"); name aerobic (not "with air"); use harvested and purified language. Quorn is a brand name — the spec uses "mycoprotein."

Application 2 — Human insulin from GM bacteria

Spec wording

"A genetically modified bacterium produces human insulin. When harvested and purified this is used to treat people with diabetes."

The process (Foundation level — spec 4.6.2.4)

The human insulin gene is "cut out" of a human chromosome.

The gene is transferred into a bacterium, making it a genetically modified bacterium.

The GM bacteria are grown in large numbers (e.g. in a fermenter); they produce human insulin as they grow.

The insulin is harvested and purified, then used to treat people with diabetes.

HT enrichment — 4.6.2.4 HT only

At Higher Tier, spec 4.6.2.4 adds the enzymatic detail: enzymes are used to isolate the required gene; the gene is inserted into a vector, usually a bacterial plasmid or a virus; the vector inserts the gene into the recipient cells. Foundation-tier students don't need the vector/plasmid mechanism.

Why this matters

Before GM insulin, diabetics relied on insulin extracted from pig or cow pancreases — limited supply, slight molecular differences could trigger immune reactions. GM bacterial insulin is identical to human insulin, can be produced in vast quantities, and is suitable for everyone.

Application 3 — GM crops

Spec wording

"GM crops could provide more food or food with an improved nutritional value such as golden rice."

Two distinct purposes:

Purpose 1 — More food

Crops can be genetically engineered to be resistant to pests, diseases, or herbicides, increasing yield. Bt cotton (insect-resistant) and herbicide-resistant soya are real-world examples.

Purpose 2 — Improved nutritional value (golden rice)

Golden rice is the spec example. It is genetically modified to produce β-carotene (which the body converts to vitamin A). It was developed for regions where vitamin A deficiency causes childhood blindness and immune problems.

Cross-module link

The mechanism of genetic engineering is covered in Lesson 6.07 (4.6.2.4). Be ready to combine: GM technology (Module 6) → biotech applications (Module 7).

Evaluating GM crops

The spec (and WS 1.4) expects you to evaluate GM crops — give advantages AND disadvantages, then conclude.

Advantages

Higher yield → helps feed a growing population

Improved nutritional value (e.g. golden rice reduces vitamin A deficiency / blindness)

Resistance to pests / disease → less crop loss

Resistance to herbicides → easier weed control

Tolerance to drought or salinity → grow in marginal land

Disadvantages (MS-credit-worthy)

Long-term effects on humans / animals (when eaten) are unknown

Gene / allele may be transferred to other (wild) plants

May reduce biodiversity (or gene pool)

Increased cost of seed for farmers / cost to consumer

May affect flavour / taste of the product

Golden-rice specific: may have too much vitamin A in the diet

MS strict

AQA mark schemes consistently ignore "ethical concerns or religion" as GM disadvantages — confirmed in both Nov 2020 P2 Q2.7 (golden rice) and Jun 2024 P2 Q9.2 (GM crops). Use the concrete biological/economic disadvantages above.

Fish stock conservation

Fish stocks in many oceans are declining due to overfishing.

Describe and explain two methods used to conserve fish stocks at a sustainable level. 4 marks

M1

Control of net size — using nets with larger mesh holes. (1)

E1

This allows young / immature fish to escape, so they can survive to reach breeding age and reproduce, maintaining the population. (1)

M2

Fishing quotas — limits on the number of fish that can be caught. (1)

E2

This ensures enough adult fish remain to breed, so the population can replace fish that are caught and stocks don't collapse. (1)

"Describe and explain two methods" needs name + mechanism for each. Naming the method alone scores half marks. The mechanism for both methods links to maintaining the breeding population.

Mycoprotein production

Mycoprotein is a protein-rich food suitable for vegetarians.

Describe how mycoprotein is produced industrially. 4 marks

1

The fungus Fusarium is grown in a fermenter. (1)

2

It is grown on glucose syrup (as a carbon / energy source). (1)

3

The fermenter provides aerobic conditions (oxygen supplied). (1)

4

The biomass is harvested and purified to produce the food. (1)

This is the spec's four named elements. Each maps to one mark. Generic answers ("a fungus is grown in a tank") score zero — the specific spec terms (Fusarium, glucose syrup, aerobic, harvested and purified) are what's credited.

Evaluate GM crops

A farmer in a developing country is considering planting a genetically modified (GM) crop variety.

Evaluate the use of GM crops as a solution to food security problems. 4 marks

Pattern 13 evaluation — at least one advantage + one disadvantage + reasoning + conclusion.

A1

Advantage: GM crops can have higher yields (resistance to pests / disease / drought) — more food produced per hectare to feed a growing population. (1)

A2

Advantage: Improved nutritional value (e.g. golden rice produces β-carotene, reducing vitamin A deficiency / blindness). (1)

D1

Disadvantage:Genes/alleles may transfer to wild plants, potentially reducing biodiversity in the surrounding ecosystem. (1)

D2

Disadvantage: Long-term effects on humans/animals are unknown; increased cost of GM seed may be unaffordable for poor farmers; people may consume too much vitamin A if they eat lots of golden rice. (1)

Critical: AQA MS — confirmed in Nov 2020 P2 Q2.7 (golden rice) and Jun 2024 P2 Q9.2 (GM crops) — explicitly ignores "ethical concerns or religion." Credit goes to concrete biological/economic mechanisms: unknown effects (must be qualified, not "may harm humans" alone), gene transfer to wild plants, biodiversity loss, cost, flavour. Golden rice specifically: "too much vitamin A in diet" is also MS-credited. Pattern 13 needs both sides + conclusion.

Examiner alerts

Alert 1 — Spec-strict on mycoprotein language

Four phrases the MS credits: Fusarium (genus, not "fungus" alone), glucose syrup (not "sugar"), aerobic (not "with air"), harvested and purified. Generic phrasings lose marks.

Alert 2 — Fisheries needs both methods

"Describe two methods" demands both net size AND quotas — naming only one caps at half marks. Each method also needs its mechanism (young escape / breeders preserved).

Alert 3 — GM disadvantages: concrete mechanisms

AQA MS — confirmed in both Nov 2020 P2 Q2.7 (golden rice) and Jun 2024 P2 Q9.2 (GM crops) — ignores "ethical concerns" and "religion" as disadvantages. Credit-worthy: unknown effects on humans/animals · gene transfer to wild plants · reduced biodiversity · seed costs · flavour · too much vitamin A (golden rice). Use these phrasings.

Alert 4 — Cross-link insulin to Module 6

The GM insulin process (restriction enzymes → plasmid → ligase → bacteria → fermenter) is from Lesson 6.07. Longer questions may ask both the technique (Module 6) AND the application (Module 7) — be ready to bridge.

Common errors — fix these now

✗ Weak

"Mycoprotein is made from a mushroom / algae."Wrong organism.

✓ Strong

"Mycoprotein is made from the fungus Fusarium , grown on glucose syrup in aerobic conditions."Spec verbatim.

✗ Weak

"Quotas only stop overfishing."Misses net size; only one method.

✓ Strong

"Quotas limit catch numbers; net size lets young fish escape to breed."Both methods + mechanisms.

✗ Weak

"GM crops are unnatural and wrong."MS ignores ethics/religion.

✓ Strong

"Genes may transfer to wild plants; long-term effects on humans are unknown."Concrete, MS-credited.

Recap — three things to remember

1

Two methods conserve fish stocks

Control of net size (young fish escape to breed) + fishing quotas (limits catch so adults remain to reproduce). Both maintain stocks at sustainable levels.

2

Three named biotechnology applications

Mycoprotein from Fusarium on glucose syrup in aerobic conditions (harvested + purified). Human insulin from GM bacteria for diabetes. GM crops for more food or improved nutrition (golden rice).

3

Evaluate with concrete disadvantages

For GM evaluation: name concrete disadvantages (gene transfer · biodiversity loss · unknown long-term effects · seed cost). MS ignores "ethical concerns" and "religion."

🌿 End of Module 7 — Ecology · 13 lessons · Paper 2 complete

What's next

You've now covered the whole AQA 8461 specification. Next steps: practice question banks, mark scheme analysis sessions, and full-paper timed practice. Strong work.