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11.3 Treating Diabetes

GCSE Biology · AQA · Chapter 11: Hormonal Coordination

A free GCSE Biology lesson for AQA (8461) from OBA School: type 1 and type 2 diabetes: causes, risk factors and treatments. Watch the video, read the explanation and worked examples, then try the revision questions. You can work through the full lesson, with every video, practice quizzes and printable worksheets with mark schemes, in our free online course.

What you will learn

  • Compare the causes of type 1 and type 2 diabetes
  • Describe how type 1 diabetes is treated with insulin and why insulin is injected
  • Describe how type 2 diabetes is treated and why obesity is a risk factor
  • Interpret data about blood glucose and diabetes, and evaluate treatments

Key words

  • Diabetes: A condition in which the body cannot control its blood glucose concentration properly.
  • Type 1 diabetes: The pancreas fails to produce enough insulin. Blood glucose can rise very high.
  • Type 2 diabetes: The body cells no longer respond to insulin properly.
  • Risk factor: Something that makes a disease more likely, e.g. obesity for type 2 diabetes.
  • BMI: Body mass index = mass in kg ÷ (height in m)². A BMI of 30 or more is classed as obese.

Two types of diabetes

In diabetes the blood glucose concentration is not controlled properly. It can stay much too high, which damages blood vessels, eyes, kidneys and nerves over time.

  • Cause; Type 1 diabetes The pancreas fails to produce enough insulin; Type 2 diabetes Body cells no longer respond to insulin
  • Usual start; Type 1 diabetes Often in childhood or as a young adult; Type 2 diabetes Usually in adults, but increasingly in younger people
  • Main risk factors; Type 1 diabetes Not linked to lifestyle; Type 2 diabetes Obesity, lack of exercise, age, family history
  • Main treatment; Type 1 diabetes Insulin injections (or an insulin pump); Type 2 diabetes Carbohydrate-controlled diet and exercise; medicines if needed

Worked example: reading the graph

How can you tell which person has diabetes?
Their blood glucose starts higher (7.8 compared with 5.0 mmol per litre), rises much further (to about 14.6) and does not fall back to the starting level, because there is not enough insulin.

Answer: the higher curve that stays high

Treating type 1 diabetes

  • Insulin injections, usually into the fat under the skin, often before meals. Some people use an insulin pump.
  • Patients check their blood glucose (finger-prick test or a sensor) so they can match the insulin dose to what they eat and how active they are.
  • Insulin must be injected. It is a protein, so if it were swallowed it would be digested by protease enzymes in the gut.
  • Too much insulin, or exercise without eating, can make blood glucose fall too low.

Other treatments are used or being researched: pancreas transplants and transplants of the insulin-making cells. These can stop the need for injections, but donors are in short supply and patients must take drugs for life to stop their immune system rejecting the transplant. Scientists are also researching stem cells that could be made into insulin-producing cells.

Key fact: Type 1 = not enough insulin → treat with insulin. Type 2 = cells do not respond → treat with diet and exercise first.

Treating type 2 diabetes

  • A carbohydrate-controlled diet: fewer sugary foods, so blood glucose does not rise as much after meals.
  • Regular exercise: muscles take up more glucose for respiration, and cells respond better to insulin.
  • Losing weight if overweight. Medicines can be added if diet and exercise are not enough; some people later need insulin.

Obesity is a major risk factor for type 2 diabetes. The bar chart shows made-up survey data of the kind doctors collect.

Worked example: BMI and risk

A man has a mass of 102 kg and a height of 1.82 m. Calculate his BMI.
BMI = 102 ÷ 1.82² = 102 ÷ 3.3124 = 30.79…
His BMI is over 30, so he is classed as obese and is at higher risk of type 2 diabetes.

Answer: BMI = 30.8 (3 s.f.)

Evaluating data and treatments

Data showing that more obese people have type 2 diabetes is a correlation. On its own it does not prove that obesity causes diabetes, but scientists have also found a mechanism: excess body fat makes cells respond less well to insulin.

  • Insulin injections; Advantages Reliable, widely available, dose can be adjusted; Disadvantages Several injections a day; regular testing; risk of low blood glucose
  • Pancreas transplant; Advantages May stop the need for injections; Disadvantages Major surgery; few donors; lifelong immunosuppressant drugs
  • Diet and exercise (type 2); Advantages Cheap, no side effects, improves general health; Disadvantages Needs long-term willpower; may not be enough on its own

Exam tip: In an “evaluate” question, give advantages and disadvantages, then finish with a justified conclusion.

Common mistakes

  • Saying type 2 diabetes means the pancreas makes no insulin. In type 2 the cells do not respond to insulin.
  • Saying insulin can be taken as a tablet. It is a protein and would be digested.
  • Saying people with type 1 diabetes caused it by their lifestyle. Type 1 is not caused by diet or weight.
  • Treating a correlation as proof. A link between obesity and diabetes in data does not prove cause on its own.

Revision questions

Try these, then check your answers below each one.

Question 1. What is usually the first treatment for type 2 diabetes? (Choose from: A carbohydrate-controlled diet and regular exercise, A pancreas transplant, Insulin tablets, Antibiotics.)

Answer: A carbohydrate-controlled diet and regular exercise

Working: Type 2 diabetes is first treated with a carbohydrate-controlled diet and exercise.

Question 2. True or false? People with type 1 diabetes can take insulin as a tablet, because it is absorbed in the gut.

Answer: False

Working: False. Insulin is a protein, so it would be digested by protease enzymes; it must be injected.

Question 3. Calculate the BMI of a person with a mass of 85 kg and a height of 1.70 m. Use BMI = mass ÷ height². Give your answer to 1 decimal place.

Answer: 29.4

Working: 85 ÷ 1.70² = 85 ÷ 2.89 = 29.4

Related lessons

Continue in the full course

This lesson is section 11.3 (AGCBH1103) of our free GCSE Biology course for AQA. In the full course you get every video for this section, a self-marking practice quiz, a printable worksheet with a mark scheme, chapter tests, and your progress saved. Go to the full GCSE Biology course.

 

 

 

 

 

 

 

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