Mark Scheme

Section A — Structured Questions (72 marks)

Question 1

(a)(i)

• Hydrogen gas is produced / a gas is produced [1]
• The gas escapes from the flask / is not contained [1] [Accept: mass of gas lost] [Reject: "atoms disappear" or "mass is destroyed"]

(a)(ii)

• 0.20 g [1] [Accept: 87.45 – 87.25 = 0.20]

(a)(iii)

• All six points plotted correctly (± ½ small square) [2]
• Smooth curve of best fit through all points [1] [Deduct 1 mark for each incorrectly plotted point, maximum deduction 2] [Line must be a curve, not straight line segments]

(b)(i)

• Bubbles / fizzing / effervescence [1]
• Magnesium dissolves / disappears / gets smaller [1] [Accept: solution becomes warm/hot] [Do not accept: "the magnesium melts"]

(b)(ii)

• The graph would have the same final mass / same total mass loss [1]
• The mass would decrease more quickly / steeper gradient initially [1]
• Because higher temperature increases kinetic energy of particles / more frequent collisions / more energetic collisions / greater proportion of collisions exceed activation energy [1]

(c)

• The rate of reaction would be faster / reaction would be quicker [1]
• Because powder has a greater surface area (for collisions) [1] [Accept: more particles exposed / smaller pieces]

[Total: 13 marks]

Question 2

(a)(i)

• Active transport [1] [Do not accept: osmosis, diffusion, or absorption without qualification]

(a)(ii)

• To make proteins / amino acids [1]
• For growth / to make new cells / to make enzymes [1] [Accept: for making chlorophyll / nucleic acids / DNA]

(b)(i)

• Mr of NH₄NO₃ = 14 + (4 × 1) + 14 + (3 × 16) = 80 [1]
• Mass of nitrogen = 28 [1]
• Percentage = (28 ÷ 80) × 100 = 35% [1] [Award full marks for correct answer with working] [Award 2 marks for correct answer without working if clearly correct Mr used]

(b)(ii)

• Mass of nitrogen = 200 × 0.35 [1]
• = 70 kg [1] [Accept: 200 × (28/80)]

(c)(i)

• Rain washes fertilizer from soil / leaching / run-off (into streams/rivers/lakes) [1]

(c)(ii)

• Algae / water plants grow rapidly / algal bloom [1]
• Algae die [1]
• Bacteria / decomposers break down dead algae / increase in decomposers [1]
• Bacteria use oxygen / respire / reduce oxygen concentration in water [1] [Maximum 4 marks. Accept: fish cannot respire/suffocate as consequence of low oxygen] [Must show cause and effect sequence for full marks]

(d) Advantage (any one):

• Improves soil structure [1]
• Releases nutrients slowly / less leaching
• Organic / natural / sustainable
• Cheaper / readily available

Disadvantage (any one):

• Bulky / difficult to transport / difficult to spread [1]
• Lower concentration of nutrients / requires more to achieve same effect
• May contain weed seeds / pathogens
• Unpleasant smell

[Total: 15 marks]

Question 3

(a)(i)

• A: cell wall [1]
• D: (circular) DNA / chromosome / genetic material / nucleoid [1] [Accept: bacterial chromosome / plasmid for D if diagram shows circular structure]

(a)(ii)

• Site of (chemical) reactions / where enzymes are found / where metabolism occurs [1] [Accept: contains dissolved substances / cytosol]

(b)(i)

• The DNA replicates / copies / duplicates [1]
• The cell grows / cytoplasm increases [1]
• The cell divides into two (identical) cells / two daughter cells produced [1] [Must be in logical sequence for full marks]

(b)(ii)

• Number of 20-minute periods = 120 minutes ÷ 20 = 6 [1]
• Number of bacteria = 500 × 2⁶ = 500 × 64 = 32,000 [1] [Accept: 32000 or 3.2 × 10⁴]

(c)(i)

• Antibiotics [1]

(c)(ii)

• Antibiotics kill bacteria / damage bacterial cells [1]
• Viruses are not cells / do not have cell walls / have different structure (from bacteria) / reproduce inside host cells [1] [Accept: antibiotics target bacterial structures that viruses do not have]

(d)

• Random mutations occur / genetic variation exists in the population [1]
• Some bacteria have alleles/genes that make them resistant to the antibiotic [1]
• When antibiotic is present, non-resistant bacteria die / resistant bacteria survive [1]
• Resistant bacteria reproduce / pass on resistance alleles to offspring / increase in frequency [1] [Must show understanding of: variation, selection pressure, differential survival, inheritance]

[Total: 15 marks]

Question 4

(a)(i)

• A compound containing hydrogen and carbon only [1] [Both elements must be mentioned; "only" is essential]

(a)(ii)

• Crude oil is heated / vaporized [1]
• Vapors rise up the column / tower / fractionating column [1]
• Column is cooler at the top / has a temperature gradient [1]
• Fractions condense at different temperatures / heights / smaller molecules condense higher up [1] [Maximum 3 marks]

(b)(i)

• As the number of carbon atoms increases, the boiling point increases [1] [Accept: positive correlation / directly proportional] [Must refer to both variables]

(b)(ii)

• Larger molecules have stronger intermolecular forces / van der Waals forces [1]
• More energy is needed to overcome these forces / separate the molecules [1]

(c)(i)

• 2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O [2] [Award [2] for correct equation with correct balancing] [Award [1] for correct formulas but incorrect balancing] [Accept: C₈H₁₈ + 12½O₂ → 8CO₂ + 9H₂O]

(c)(ii)

• Carbon monoxide / CO [1]
• Binds to hemoglobin / prevents oxygen transport / reduces oxygen carried by blood / poisonous / toxic [1] [Accept: soot/carbon/particulates for first mark, with appropriate harm]

(d)(i)

• High temperature / 600–700°C / heat [1]
• Catalyst / zeolite / aluminium oxide / silica [1]

(d)(ii)

• C₈H₁₆ [1] [Accept: octene or any C₈H₁₆ alkene]

(d)(iii)

• Produces shorter chain molecules / produces more useful fractions [1]
• Produces alkenes (which can be used to make polymers/plastics) / meets demand for petrol [1] [Accept: increases supply of fuels in high demand]

[Total: 16 marks]

Question 5

(a)(i)

• Measure the initial position of the pointer (with no load) / take zero reading [1]
• Add masses one at a time / increase force in regular intervals [1]
• Measure new position each time / measure extension / wait for spring to stop moving before reading [1]
• Repeat (readings) and calculate mean / take multiple readings [1] [Maximum 3 marks] [Accept: avoid parallax error when reading ruler]

(a)(ii)

• Wear safety goggles / eye protection [1] [Accept: stand clear in case spring breaks / clamp stand securely / use small masses]

(b)(i)

• All six points plotted correctly (± ½ small square) [2] [Deduct 1 mark for each incorrectly plotted point]
• Axes correctly labeled with quantities and units [1]

(b)(ii)

• Straight line drawn through first four points using ruler [1] [Line should pass through or very close to points at 0, 2, 4, and 6 N]

(b)(iii)

• (The extension is) directly proportional to the force / force is proportional to extension [1] [Accept: they increase together / linear relationship / obeys Hooke's law] [Do not accept: "they are proportional" without stating which increases]

(c)

• Spring constant = force ÷ extension [1]
• = 2.0 ÷ 0.015 = 133 or 4.0 ÷ 0.030 = 133 (choose point on straight line portion) [1]
• Unit: N/m or N/cm [1] [Accept any value between 130–135 N/m if correct unit given] [If N/cm used, accept 1.3–1.35 N/cm]

(d)

• The spring has exceeded its elastic limit / limit of proportionality / been permanently deformed / inelastically deformed [1] [Accept: the spring will not return to its original length] [Do not accept: "the spring has broken" or "the spring has stretched"]

[Total: 13 marks]

Section B — Extended Response (48 marks)

Question 6

Mark scheme: Levels of response

Level 4 (19–24 marks):

• Comprehensive evaluation covering multiple aspects (environmental, economic, reliability)
• Detailed analysis of data trends with specific numerical references
• Balanced discussion of advantages and disadvantages of both renewable and non-renewable sources
• Well-developed chains of reasoning showing clear understanding of scientific principles
• Appropriate use of scientific terminology throughout
• Clear conclusion reached that is supported by the evidence and arguments presented
• Answer is coherent, logical, and well-organized

Level 3 (13–18 marks):

• Good evaluation covering several aspects
• Analysis of data with some numerical references
• Discussion of advantages and disadvantages of both types of sources, but may be less balanced
• Generally sound reasoning with good understanding of scientific principles
• Generally appropriate use of scientific terminology
• Conclusion reached but may not be fully developed or supported
• Answer is generally well-organized

Level 2 (7–12 marks):

• Limited evaluation, may focus mainly on one aspect
• Some reference to data but limited analysis
• Some advantages and disadvantages stated but discussion lacks depth
• Some relevant scientific knowledge but with gaps or errors
• Some appropriate terminology but may be imprecise
• Limited or absent conclusion
• Answer may lack clear structure

Level 1 (1–6 marks):

• Very limited evaluation
• Minimal or no reference to data
• Simple statements about advantages or disadvantages with little development
• Limited scientific knowledge, may contain errors
• Little use of scientific terminology
• No conclusion or conclusion not related to question
• Answer lacks coherent structure

0 marks: No creditable content

Indicative content (not exhaustive):

Analysis of data:

• Coal decreased from 45% to 28% (17 percentage point decrease)
• Wind increased from 5% to 15% (10 percentage point increase / trebled)
• Solar increased from 1% to 6% (6 percentage point increase / sixfold increase)
• Overall trend: shift from non-renewable (especially coal) to renewable sources
• Natural gas increased slightly (replacing some coal)
• Nuclear and hydroelectric relatively stable

Advantages of renewable energy:

• Will not run out / sustainable
• No greenhouse gas emissions during generation / reduces climate change
• No air pollution (sulfur dioxide, nitrogen oxides, particulates)
• Wind and solar have low running costs
• Becoming more economically competitive

Disadvantages of renewable energy:

• Unreliable / dependent on weather conditions / intermittent supply
• Requires energy storage solutions or backup power
• High initial/capital costs
• Visual/noise pollution (wind turbines)
• Requires large areas of land
• Lower energy density

Advantages of non-renewable energy:

• Reliable / continuous supply / baseload power
• High energy density / concentrated energy source
• Existing infrastructure already in place
• Can respond quickly to demand changes
• Relatively cheap (at present)

Disadvantages of non-renewable energy:

• Finite resources / will eventually run out
• Produces greenhouse gases / contributes to climate change
• Air pollution / health impacts
• Environmental damage from extraction
• Nuclear waste disposal problems
• Oil spills / mining accidents

Economic factors:

• Cost of renewable technology decreasing
• Fossil fuel prices volatile
• Job creation in renewable sector
• Cost of climate change impacts

Environmental factors:

• Climate change / global warming
• Habitat destruction
• Acid rain
• Health impacts of air pollution

Reliability/security factors:

• Energy storage technology developing
• Need for diverse energy mix
• Energy security / reducing dependence on imports
• Grid infrastructure requirements

Possible conclusions:

• Transition to renewables is necessary but must be managed carefully
• Mix of sources needed to ensure reliability
• Continued role for some non-renewable as baseload/backup
• Pace of change depends on technology development and political will

[Total: 24 marks]

Question 7

(a) [6 marks]

Mark scheme:

• Temperature receptors / thermoreceptors detect the increase / in skin or hypothalamus [1]
• Hypothalamus / thermoregulatory center (in brain) coordinates response [1]
• Vasodilation / arterioles near skin surface dilate / widen [1]
• More blood flows near skin surface / more heat lost by radiation [1]
• Sweat glands produce more sweat [1]
• Evaporation of sweat removes heat / cools the body [1]

[Accept: hairs lie flat (1 mark only if other points made)] [Do not accept: "pores open"]

(b) [10 marks]

Mark scheme:

How glucose enters bloodstream:

• Carbohydrates are digested / broken down (by enzymes) [1]
• Into glucose / simple sugars [1]
• Glucose is absorbed (in small intestine) / passes into blood [1]

Detection and pancreas role:

• Blood glucose concentration rises / detected [1]
• (Detected by) the pancreas [1]

Role of insulin:

• Pancreas secretes / releases insulin [1]
• Insulin is a hormone (carried in blood to target organs) [1]

How glucose is removed:

• Insulin causes liver / muscle cells to take up glucose [1]
• Glucose is converted to glycogen (for storage) [1]
• Blood glucose concentration returns to normal / decreases [1]

[Maximum 10 marks] [Award marks for clear understanding of sequence and mechanism] [Accept: insulin increases cell permeability to glucose / makes cells more permeable to glucose]

(c)(i) [4 marks]

Type 1:

• Pancreas does not produce (enough) insulin / no insulin production [1]
• Usually develops in childhood / young people / genetic / autoimmune [1]

Type 2:

• Cells do not respond to insulin / insulin resistance [1]
• Or pancreas does not produce enough insulin [1]
• Usually develops later in life / associated with lifestyle [1] [Maximum 2 marks for Type 2]

[Total marks for (c)(i): 4 marks - 2 for Type 1, 2 for Type 2]

(c)(ii) [4 marks]

• Increased obesity / more people overweight [1]
• Poor diet / high sugar intake / high fat intake / processed foods [1]
• Lack of exercise / sedentary lifestyle [1]
• Aging population / people living longer [1]

[Accept: genetic predisposition becoming more expressed] [Accept: increased screening / better diagnosis] [Maximum 4 marks, must show understanding that lifestyle factors are primary cause]

[Total: 24 marks]

Sample Answers with Examiner Commentary

Question 6 — Sample Answers

Grade A (high distinction) answer*

The data shows a clear shift from non-renewable to renewable energy sources between 2010 and 2020. Coal generation decreased significantly from 45% to 28%, while renewable sources increased substantially – wind grew from 5% to 15% (trebling in proportion) and solar from 1% to 6% (a sixfold increase). This reflects growing concerns about climate change and air pollution, as well as improving economics of renewable technology.

Renewable energy sources offer several major advantages. They are sustainable and will not be depleted, unlike fossil fuels which are finite resources. Wind and solar power produce no greenhouse gas emissions during generation, helping to mitigate climate change and meet international carbon reduction targets. They also produce no air pollutants such as sulfur dioxide or particulates, which cause respiratory problems and acid rain. Once installed, renewable sources have very low running costs as the "fuel" (wind, sunlight) is free.

However, renewable sources have significant limitations. Their intermittent nature is a critical problem – wind turbines only generate when wind speeds are suitable, and solar panels are ineffective at night or in cloudy conditions. This unreliability means they cannot provide baseload power without expensive energy storage systems or backup from other sources. The data shows hydroelectric remaining stable at only 4%, likely because suitable sites are limited. Renewable installations also require large areas of land and can cause visual pollution and habitat disruption.

Non-renewable sources, particularly natural gas (which increased from 30% to 35%, partially replacing coal), remain important because they provide reliable, continuous power that can respond rapidly to demand changes. The existing infrastructure for fossil fuels represents a massive investment that cannot be abandoned overnight. Nuclear power, though declining slightly in the data, produces no greenhouse gases during operation and has very high energy density, though it faces public concerns about safety and waste disposal.

The main disadvantages of non-renewable sources are environmental. Burning fossil fuels releases carbon dioxide, the primary greenhouse gas driving climate change, as well as harmful pollutants. Coal is particularly problematic, producing more CO₂ per unit energy than gas, which likely explains why coal decreased most dramatically in the data while gas increased slightly. Fossil fuels will eventually be exhausted, creating long-term energy security risks. There are also considerable environmental and health costs associated with extraction – mining accidents, oil spills, and habitat destruction.

Economically, renewable energy is becoming increasingly competitive as technology improves and economies of scale develop, which helps explain the rapid growth shown in the data. However, the high initial capital costs remain a barrier, particularly for developing nations. The cost of inaction on climate change – extreme weather, sea level rise, agricultural disruption – must also be considered.

In conclusion, the data reflects a necessary and beneficial transition towards renewable energy, driven by environmental concerns and improving economics. However, a complete transition faces significant technical challenges, particularly regarding reliability and energy storage. The optimal strategy is likely a diverse energy mix that maximizes renewable generation while maintaining sufficient reliable backup capacity from lower-carbon sources like natural gas and nuclear. The pace of transition should be as rapid as technological and economic constraints allow, with continued investment in storage technology, grid infrastructure, and research into emerging solutions. The data suggests this transition is well underway and should be accelerated.

Mark: 24/24

Examiner commentary: This is an exemplary response demonstrating all the characteristics of Level 4. The candidate provides comprehensive analysis of the data with specific numerical references, systematically evaluates both renewable and non-renewable sources across environmental, economic, and reliability dimensions, uses sophisticated scientific terminology accurately throughout, and develops well-reasoned arguments that lead logically to a balanced, evidence-based conclusion. The answer is exceptionally well-structured and demonstrates deep understanding of the complex trade-offs involved in energy policy.

Grade C (pass) answer

The data shows that renewable energy increased between 2010 and 2020, while coal decreased from 45% to 28%. Wind power increased the most, going from 5% to 15%, and solar also increased from 1% to 6%. This shows that the country is moving towards cleaner energy.

Renewable energy is good because it doesn't run out and doesn't cause pollution. Wind turbines and solar panels don't produce carbon dioxide so they don't contribute to global warming. This is important because climate change is a big problem. Renewable energy is also becoming cheaper which is why more of it is being used as shown in the data.

However, renewable energy has problems. Wind turbines only work when it's windy and solar panels don't work at night. This means they can't provide electricity all the time, which is a problem. They also need a lot of space and some people think wind turbines are ugly.

Non-renewable energy like coal and gas are good because they work all the time and can provide reliable electricity. We already have power stations that use them. But they cause problems too. They produce carbon dioxide which causes global warming, and coal also produces pollution that is bad for people's health. Eventually they will run out because they are finite resources.

Nuclear power is shown in the data and it stayed about the same. Nuclear is good because it produces a lot of energy and no carbon dioxide, but it produces dangerous waste that lasts for thousands of years.

The data shows natural gas increased a bit from 30% to 35%. This might be because it's cleaner than coal but still reliable.

In conclusion, I think renewable energy is better for the environment but we still need some non-renewable energy because renewables aren't reliable enough yet. The country should keep increasing renewable energy like it has been doing. A mixture of different types is probably best so we have reliable electricity but don't damage the environment too much.

Mark: 14/24

Examiner commentary: This response demonstrates characteristics of Level 3. The candidate shows understanding of the main issues and makes several valid points about advantages and disadvantages of different energy sources. Data is referenced, though analysis is relatively superficial. The scientific understanding is generally sound but lacks the depth and sophistication of higher-level responses. Key omissions include limited discussion of economic factors, insufficient detail on the mechanisms of environmental impacts, and lack of specific consideration of energy storage or grid infrastructure issues. The conclusion is reasonable but could be better supported by the preceding arguments. To reach Level 4, the candidate needed to develop points more fully, provide more specific data analysis, and demonstrate more sophisticated understanding of the interconnected issues.

Grade E (near miss) answer

The data shows that renewable energy went up and non-renewable went down between 2010 and 2020. Wind and solar increased but coal decreased.

Renewable energy is good for the environment because it is clean and doesn't pollute. Wind turbines use wind to make electricity and solar panels use the sun, so they are free and will never run out. This is why they are better than fossil fuels. They are also safer than nuclear power which can explode like Chernobyl.

Non-renewable energy is bad because it pollutes the environment. Coal and oil produce smoke which causes global warming. When we burn fossil fuels they release carbon dioxide which is poisonous and makes the Earth hotter. This causes ice caps to melt and polar bears to die. Fossil fuels will run out in the future so we won't be able to use them anyway.

One problem with renewable energy is that wind turbines kill birds and solar panels don't work when it's cloudy. Also wind turbines are noisy and ugly.

The data shows that the country is using more renewable energy which is good for the planet. Natural gas went up a bit which is better than coal.

I think we should use 100% renewable energy as soon as possible to stop global warming. Fossil fuels are destroying the planet and we need to stop using them. The data shows we are moving in the right direction but we need to do it faster. Countries should ban fossil fuels and only use wind and solar power.

Mark: 8/24

Examiner commentary: This response falls within Level 2. While the candidate demonstrates some basic understanding and shows awareness that renewable energy has environmental benefits, there are several significant weaknesses. The analysis of data is minimal and superficial. There is a common misconception that carbon dioxide is "poisonous" (it is a greenhouse gas but not poisonous at atmospheric concentrations). The candidate fails to recognize the key issue of reliability and baseload power – the suggestion to move to "100% renewable energy as soon as possible" ignores the practical challenges of intermittency and energy storage. The evaluation is one-sided and lacks balance; non-renewable sources are dismissed entirely without acknowledging their current necessity for reliable power. Scientific terminology is sometimes imprecise. To improve, the candidate needs to: develop a more balanced evaluation recognizing legitimate advantages of both energy types, understand and explain the reliability issue more clearly, avoid oversimplification, analyze the data more thoroughly with specific numerical references, and reach a more nuanced, realistic conclusion supported by evidence rather than assertion.

Question 7(b) — Sample Answers

Grade A (high distinction) answer*

When a person eats a meal containing carbohydrates, the carbohydrates are digested by enzymes in the digestive system. Amylase in the mouth and small intestine breaks down starch into maltose, and maltase breaks maltose into glucose molecules. The glucose is absorbed through the wall of the small intestine into the bloodstream by diffusion and active transport, causing blood glucose concentration to rise.

The rise in blood glucose is detected by receptor cells in the pancreas. In response, the pancreas secretes the hormone insulin into the bloodstream. Insulin is transported in the blood to target organs, particularly the liver and muscles.

Insulin has several effects that reduce blood glucose concentration. It makes cell membranes more permeable to glucose, allowing glucose to enter cells more rapidly. More importantly, insulin activates enzymes in liver and muscle cells that convert glucose into glycogen. Glycogen is a storage polysaccharide that can be stored in the liver and muscles without affecting blood water potential. This process is called glycogenesis.

As glucose is taken up by cells and converted to glycogen, the blood glucose concentration decreases and returns to the normal level of approximately 90 mg per 100 cm³ of blood. This is an example of negative feedback – the response (lowering blood glucose) counteracts the original stimulus (high blood glucose). When blood glucose returns to normal, the pancreas reduces insulin secretion.

This homeostatic mechanism ensures that blood glucose remains within narrow limits, which is essential because cells require a constant supply of glucose for respiration, particularly brain cells which cannot use other respiratory substrates. The system also prevents damage that would be caused by excessively high blood glucose levels, such as osmotic imbalance and damage to blood vessels.

Mark: 10/10

Examiner commentary: This is an outstanding answer that demonstrates comprehensive understanding of the entire process from digestion to homeostatic regulation. The candidate provides a clear, logical sequence covering all required aspects: specific details of digestion (naming enzymes and products), absorption mechanisms, detection by the pancreas, insulin secretion and action (including specific mechanisms like increasing membrane permeability and activating enzymes), conversion to glycogen with correct terminology, and the return to normal levels. The answer also demonstrates broader understanding by explaining negative feedback and why the regulation is physiologically important. The scientific terminology is precise throughout.

Grade C (pass) answer

When a person eats carbohydrates, they are broken down by enzymes into glucose. The glucose is absorbed in the small intestine and passes into the blood. This makes the blood glucose level increase.

The pancreas detects that blood glucose is high. It responds by producing insulin. Insulin is a hormone which travels in the blood to different organs.

Insulin makes the liver take glucose out of the blood. The glucose is converted into glycogen which is stored in the liver. This is important because glycogen doesn't dissolve in the blood so it can be stored. Some glucose is also stored in the muscles as glycogen.

Because glucose is being removed from the blood and stored as glycogen, the blood glucose level goes back down to normal. This is important because the body needs to keep blood glucose constant for cells to work properly.

If blood glucose wasn't controlled it could become too high which would be dangerous. This is what happens in diabetes when the insulin system doesn't work.

Mark: 6/10

Examiner commentary: This is a solid mid-level response that covers the basic sequence of events and demonstrates satisfactory understanding. The candidate correctly identifies digestion of carbohydrates to glucose, absorption, pancreatic detection, insulin secretion, conversion to glycogen, and return to normal levels. However, several details are missing or imprecise: no mention of specific enzymes, limited detail on absorption mechanisms, unclear that the pancreas secretes insulin (says "produces"), the mechanism of insulin action is oversimplified (doesn't mention cell membrane permeability or enzyme activation), and the concept of homeostasis/negative feedback is not explicitly stated though implied. To achieve higher marks, the candidate needed more specific detail about mechanisms and more precise scientific terminology.

Grade E (near miss) answer

When you eat food with carbohydrates like bread or pasta, it gets digested into glucose in your stomach. The glucose goes into your blood which makes blood sugar go up.

Your pancreas notices that blood sugar is high. The pancreas makes insulin which is released into the body. Insulin is important because it controls blood sugar.

Insulin makes the glucose turn into glycogen. Glycogen is stored in the liver so that it can be used later when you need energy. This makes the blood sugar go back to normal levels.

This is important because your body needs the right amount of sugar in your blood. Too much sugar is bad for you and can make you sick. The pancreas and insulin make sure the blood sugar stays at the right level.

People with diabetes don't have enough insulin so their blood sugar is too high. They have to inject insulin to control it.

Mark: 3/10

Examiner commentary: This response demonstrates limited understanding appropriate to Level 1, though it does contain some correct basic ideas. The candidate shows awareness of the general sequence (eating carbohydrates → blood glucose rises → pancreas responds → insulin → glycogen storage → blood glucose falls) but lacks essential detail and contains significant omissions and imprecision. Key problems include: digestion is oversimplified and incorrectly located in "stomach" rather than throughout digestive system with small intestine as main site of absorption, no mention of enzymes, the mechanism by which glucose enters the blood is omitted entirely, how insulin actually works at the cellular level is not explained ("makes glucose turn into glycogen" is too vague and doesn't mention target organs or cellular mechanisms), no mention that insulin is a hormone or how it travels to target organs, and terminology is imprecise throughout ("blood sugar" instead of blood glucose concentration, "released into the body" rather than "secreted into bloodstream"). To improve to a passing grade, the candidate must provide more specific detail about each stage, use correct scientific terminology, and explain mechanisms rather than just stating outcomes.