AQA GCSE Combined Science (8464), Higher tier · Biology › Homeostasis and response › Hormonal coordination in humans
Practise Control of blood glucose concentration. 14 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
How the pancreas uses insulin, and at Higher tier glucagon, to keep blood glucose within narrow limits, and the causes and treatments of Type 1 and Type 2 diabetes. Expect graph questions on glucose levels after a meal, 'compare Type 1 and Type 2 diabetes', and 6-mark negative feedback explanations.
Grade by grade
What you need to be able to do, from the first marks up to the top grade.
3
Name the organ that controls blood glucoseThe pancreas monitors and controls blood glucose concentration.
4
Describe how insulin lowers blood glucoseInsulin makes glucose move from the blood into cells; liver and muscle cells store it as glycogen.
5
Compare the causes of Type 1 and 2Type 1: the pancreas does not make enough insulin. Type 2: body cells stop responding to insulin.
5
Describe treatments for each type of diabetesType 1: insulin injections. Type 2: a carbohydrate-controlled diet and an exercise regime.
6
Interpret blood glucose graphsDescribe and explain the rise and fall of glucose after a meal, with and without diabetes.
7
Describe how glucagon raises blood glucoseGlucagon causes glycogen to be converted into glucose, which is released into the blood.
8
Explain insulin and glucagon in negative feedbackThe two hormones act in opposite directions, returning glucose to normal whenever it rises or falls.
Notes
Insulin
Blood glucose concentration is monitored and controlled by the pancreas.
If blood glucose is too high (e.g. after a meal), the pancreas releases the hormone insulin into the blood.
Insulin causes glucose to move from the blood into the cells.
In liver and muscle cells, excess glucose is converted into glycogen for storage. Blood glucose falls back to normal.
Glucagon and negative feedback grade 7+
If blood glucose is too low (e.g. after exercise or a long time without food), the pancreas releases the hormone glucagon.
Glucagon causes glycogen to be converted into glucose, which is released into the blood, so blood glucose rises.
Insulin and glucagon work together in a negative feedback cycle: a rise triggers insulin, which brings the level down; a fall triggers glucagon, which brings it back up.
Diabetes
Type 1 diabetes: the pancreas fails to produce enough insulin, so blood glucose is uncontrolled and can rise to dangerously high levels. It is normally treated with insulin injections.
Type 2 diabetes: the body cells no longer respond to the insulin produced by the pancreas. Common treatments are a carbohydrate-controlled diet and an exercise regime.
Obesity is a risk factor for Type 2 diabetes.
People with Type 1 diabetes test their blood glucose so they can match the insulin dose to what they eat and how active they are.
Cheatsheet
The pancreas monitors and controls blood glucose
Glucose too high → insulin → glucose moves into cells → stored as glycogen in liver and muscle cells
Glucose too low → glucagon → glycogen converted to glucose → released into the blood grade 7+
Type 1: pancreas makes too little insulin → insulin injections
Type 2: cells no longer respond to insulin → carbohydrate-controlled diet and exercise
Obesity is a risk factor for Type 2 diabetes
Glucose = the sugar; glycogen = the store; glucagon = the hormone
How to answer each type of question
Describe how blood glucose returns to normal after a meal
3 marks5
The pancreas detects the high glucose level and releases insulin.
Insulin makes glucose move from the blood into cells.
Liver and muscle cells convert excess glucose to glycogen.
Example. After a meal, a person's blood glucose concentration increases. Describe how the body brings the blood glucose concentration back to normal.
Show the model answer
The pancreas detects the high blood glucose concentration and releases insulin (1). Insulin causes glucose to move from the blood into cells (1). In liver and muscle cells, excess glucose is converted to glycogen for storage (1).
Compare Type 1 and Type 2 diabetes
2 to 4 marks5
Give the cause of each type, linked with 'whereas'.
Give the treatment of each type, linked with 'whereas'.
Example. Compare the causes and treatments of Type 1 and Type 2 diabetes.
Show the model answer
In Type 1 the pancreas does not produce enough insulin (1), whereas in Type 2 the body cells no longer respond to insulin (1). Type 1 is treated with insulin injections (1), whereas Type 2 is usually treated with a carbohydrate-controlled diet and exercise (1).
Interpret blood glucose data
3 to 4 marks6
Read values carefully, with units.
For a percentage change: change ÷ starting value × 100.
Explain the pattern using insulin: with Type 1 diabetes too little insulin is made, so glucose stays high.
Example. Two people each drink a glucose solution. In person A, who does not have diabetes, blood glucose rises from 5 to 8 mmol/dm3 and returns to 5 mmol/dm3 after 2 hours. In person B, who has Type 1 diabetes, it rises from 8 to 14 mmol/dm3 and is still 13 mmol/dm3 after 2 hours. (a) Calculate the percentage increase in person B's blood glucose concentration. (b) Explain why person B's blood glucose concentration stays high.
Show the model answer
(a) 14 − 8 = 6 (1); 6 ÷ 8 × 100 = 75% (1) (b) Person B's pancreas does not produce enough insulin (1), so glucose is not moved from the blood into cells / not converted to glycogen (1).
6-mark: explain how insulin and glucagon control blood glucose
6 marks8
Deal with the rise first: pancreas, insulin, glucose into cells, glycogen.
Then the fall: pancreas, glucagon, glycogen to glucose, released into the blood.
Use the term negative feedback and say each response returns the level to normal.
Example. A person eats a large meal and then goes without food for several hours. Explain how their body keeps their blood glucose concentration within normal limits over this time.
Show the model answer
Indicative content: glucose from the digested meal is absorbed and blood glucose rises; the pancreas detects the rise and releases insulin; insulin causes glucose to move from the blood into cells; in liver and muscle cells excess glucose is converted to glycogen; blood glucose falls back to normal; later, glucose is used in respiration and blood glucose falls below normal; the pancreas releases glucagon; glucagon causes glycogen to be converted into glucose, which is released into the blood; blood glucose rises back to normal; the two hormones work in a negative feedback cycle. Level 3 (5 to 6 marks): clear, logically linked explanation of both the insulin and the glucagon responses. Level 2 (3 to 4 marks): one response explained in detail, or both with gaps. Level 1 (1 to 2 marks): simple statements, e.g. 'insulin lowers blood glucose'.
Shortcuts and memory tricks
Glucagon is released when glucose is gone (too low).
Insulin puts glucose IN to cells.
Type 1: the pancreas is the problem. Type 2: the cells are the problem.
Insulin and glucagon are opposites, like a heater and a fan controlled by the same thermostat.
Where marks are lost
Mixing up glucagon (the hormone) and glycogen (the storage carbohydrate).
Saying insulin turns glucose into glycogen in the blood. Insulin makes glucose move into cells; the conversion happens in liver and muscle cells.
Saying people with Type 2 diabetes make no insulin. They do make it; their cells no longer respond to it.
Dividing by the final value instead of the starting value in percentage change calculations.
Describing a graph without quoting any values from it.
Exam technique
Spell glucagon and glycogen carefully: a spelling that could be either word may not get the mark.
In 6-mark answers, cover both directions (too high and too low) and use the term negative feedback.
When describing graphs, quote values with units and times, e.g. 'rises to a peak of 8 mmol/dm3 at 30 minutes'.
Quick recall
Cover the answers and test yourself. The app has these as flashcards that come back just before you'd forget them.
Name the hormone that is released when the blood glucose concentration is too high.
Insulin
Which type of diabetes is caused by the pancreas failing to produce enough insulin?
Type 1 diabetes
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy6 marks
The concentration of glucose in the blood is controlled by hormones.
(a) Which organ monitors and controls the blood glucose concentration? Tick (✓) one box.[1]
Kidney
Liver
Pancreas
Pituitary gland
(b) Name the hormone that is released when the blood glucose concentration is too high.[1]
(c) In liver and muscle cells, excess glucose is converted into a storage substance. Name this storage substance.[1]
(d) Type 1 diabetes is normally treated with insulin injections. What is the cause of Type 1 diabetes?[1]
(e) Which two are common treatments for Type 2 diabetes? Tick (✓) two boxes.[2]
A carbohydrate-controlled diet
A course of antibiotics
An exercise programme
A kidney transplant
A vaccination
Show the answer and mark scheme
(a)Answer: Pancreas
(b)Answer: Insulin
insulin
(c)Answer: Glycogen
glycogen
(d)Answer: The pancreas does not produce enough insulin
the pancreas does not produce (enough) insulin
(e)Answer: A carbohydrate-controlled diet; An exercise programme
Question 2Medium8 marks
Two people each had a drink containing 75 g of glucose. Person A does not have diabetes. Person B has Type 1 diabetes and did not inject any insulin during the test. {fig} shows the blood glucose concentrations of both people. The solid line is person A and the dashed line is person B.
[object Object]
(a) Describe how the blood glucose concentration of person A changed between 0 and 120 minutes.[2]
(b) Explain why the blood glucose concentration of person A decreased after 30 minutes.[3]
(c) Use {fig} to give two differences between the results for person B and the results for person A.[2]
(d) What should person B do to reduce their blood glucose concentration?[1]
Show the answer and mark scheme
(a)Answer: It rose to a peak of 140 mg per 100 cm³ at 30 minutes, then fell back to 85 mg per 100 cm³ by 120 minutes
increased to a maximum / peak at 30 minutes / of 140 (mg per 100 cm³)
then decreased back to the starting value / to 85 (mg per 100 cm³) (by 120 minutes)
(b)Answer: The pancreas detected the high glucose concentration and released insulin; insulin caused glucose to move from the blood into cells, where it was stored as glycogen in liver and muscle cells
pancreas detects the high blood glucose concentration
(pancreas) releases / secretes insulin (into the blood)
(insulin) causes glucose to move from the blood into (body) cells
(in liver and muscle cells) glucose is converted to glycogen (for storage)
(c)Answer: B starts at a higher concentration; B's concentration rises higher and peaks later; B's concentration does not return to its starting value within 180 minutes
person B's concentration was higher at the start
person B's peak was higher / reached 280 compared with 140 (mg per 100 cm³)
person B's peak was later / at 90 minutes compared with 30 minutes
person B's concentration fell more slowly / did not return to the starting value
(d)Answer: Inject insulin
inject insulin
Question 3Hard8 marks
A person eats a meal that contains a lot of carbohydrate. The person then eats nothing more for the next 8 hours.
(a) Explain how the concentration of glucose in the blood is kept within normal limits during the 8 hours after the meal.[6]
(b) A person with Type 1 diabetes measures their blood glucose concentration before deciding how much insulin to inject. Suggest why.[2]
Show the answer and mark scheme
(a)Answer: Level 3 answers explain the insulin response to the rise after the meal and the glucagon response to the later fall, linked as negative feedback
carbohydrate is digested and glucose is absorbed into the blood, so blood glucose rises
the pancreas monitors / detects the rise in blood glucose
the pancreas releases insulin into the blood
insulin causes glucose to move from the blood into cells
in liver and muscle cells glucose is converted to glycogen for storage
blood glucose falls back to normal
later, as glucose is used in respiration, blood glucose falls below normal
the pancreas releases glucagon
glucagon causes glycogen to be converted into glucose, which is released into the blood
blood glucose rises back to normal; insulin and glucagon act antagonistically in negative feedback
Marked with levels of response: the full level descriptors are in the app.
(b)Answer: The dose must match the glucose concentration: too little insulin leaves the glucose too high, too much makes it fall dangerously low
too little insulin would leave blood glucose too high
too much insulin would make blood glucose fall too low