Diabetes (WJEC GCSE Biology: Combined Science)

Revision Note

Cara Head

Author

Cara Head

Expertise

Biology

Diabetes

  • Diabetes is a common disease in which a person has a high blood glucose level
  • Type 1 diabetes:
    • This is a disorder in which the pancreas fails to produce sufficient insulin to control blood glucose levels
    • Uncontrolled high blood glucose levels characterise type 1 diabetes
    • Cause:
      • Scientists think this is a result of a person’s immune system destroying the cells of the pancreas that make insulin
    • Treatment:
      • Type 1 diabetes is normally treated with insulin injections several times a day
      • Diet needs to be controlled, such as limiting simple carbohydrates which are converted quickly into glucose and cause blood sugar levels to rapidly rise
      • A pancreas transplant can be a treatment for people with Type 1 diabetes, although this is not a common procedure and is used when someone has other complications
  • Type 2 diabetes:
    • The body cells no longer respond to insulin produced by the pancreas - the person still makes insulin but their cells are resistant to it and don’t respond as well as they should
    • This can also lead to uncontrolled high blood glucose levels
    • Cause:
      • Obesity is a big risk factor for Type 2 diabetes; probably because a person who is obese may consume a diet high in carbohydrates, and over-production of insulin results in resistance to it developing
    • Treatment:
      • A carbohydrate-controlled diet and an exercise regime are common treatments for Type 2 diabetes

Detecting diabetes

  • Diabetes can be detected by the presence of glucose in urine (as excess urine is excreted from the body rather than being stored in the liver as glycogen)
  • This can be investigated practically using Benedict's solution

Method:

  1. Add equal volumes of an artificial urine sample and Benedict's solution to a test tube
  2. Gently heat the solution for five minutes
  3. If glucose is present, the solution will turn from blue to orange
  4. Repeat for other artificial urine samples

Testing artificial urine diagram

testing-a-urine-sample-for-glucose-benedicts

Samples of artificial urine can be tested for the presence of glucose using Benedict's solution

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Cara Head

Author: Cara Head

Cara graduated from the University of Exeter in 2005 with a degree in Biological Sciences. She has fifteen years of experience teaching the Sciences at KS3 to KS5, and Psychology at A-Level. Cara has taught in a range of secondary schools across the South West of England before joining the team at SME. Cara is passionate about Biology and creating resources that bring the subject alive and deepen students' understanding