5.4.4 Diabetes

Question 1

Broadly what does diabetes do?

Answer 1

• Insulin function disrupted
• Blood glucose concentration rises
• Kidneys unable to filter out excess glucose in blood so appears in urine

Question 2

Type 1 Diabetes

Answer 2

• Pancreas fails to produce sufficient insulin
• Autoimmune disease in childhood where T cells attack β cells in islets of Langerhans in pancreas (which detect high blood sugar and synthesise insulin)
• Lack of insulin affects glycogen stores so individual feels fatigued
• Treated with insulin injections and appropriate diet

Question 3

Type 2 Diabetes

Answer 3

• Usually develops in older people, more common than type 1
• Pancreas secretes insulin but receptors in the liver and fat storage tissues no longer respond to it
• Lack of response means reduced glucose uptake in these cells so a high blood glucose concentration
• β cells produce lots of insulin which causes damage
• Sugar controlled diet and exercise
• Risk factors include : Obesity, lack of exercise, high blood pressure, high cholesterol, genetics

Question 3

How does diabetes affect blood pressure?

Answer 3

• High concentrations of glucose in blood
• Decreases water potential of blood
• So water moves into blood from tissues via osmosis
• Larger volume of blood in circulatory system causing BP to increase

Question 3

How can insulin be produced using genetically modified bacteria?

Answer 3

• Recombinant DNA produces recombinant proteins
• Bacterial plasmids modified to include human insulin gene
• Recombinant plasmids inserted to E.coli and marked
• Bacteria multiply by binary fission and then the marked genes are extracted and purified

Question 4

What is recombinant DNA?

Answer 4

• DNA that has been altered by introducing nucleotides from another source

Question 5

Advantages of producing insulin via genetically modified bacteria?

Answer 5

• Identical to human insulin (genetic code is universal)
• Fewer ethical and moral concerns compared to cows and pigs
• Fewer rejection problems or allergies or side effects
• Cheap to produce in large volumes
• Useful for people with animal insulin tolerance

Question 6

How can diabetes be treated with stem cells?

Answer 6

• Differentiate into pancreatic β cells
• Newly developed pancreatic β cells transplanted into pancreas of diabetic individual
• Can produce insulin when old damaged cells are replaced