Paper 2 - Homeostatis And Glucoregulation

Question 1

Glycogenolysis

Answer 1

The hydrolysis of glycogen stored in muscle and liver

Question 2

Gluconeogenesis

Answer 2

The production of glucose from amino acids and glycerol in the liver

Question 3

When blood glucose is too high

Answer 3

1. Receptors on Beta cells from pancreas detect this
2. They release insulin into the blood
3. Insulin binds to complimentary receptors on liver and muscle cells
4. More GLUT4 proteins insert into cell membranes = cells more permeable to glucose ,and so, more is absorbed
5. Enzymes are activated in the cells stimulating glycogenesis and increased respiration rate.

Question 4

When blood glucose is too low

Answer 4

1. Receptors on alpha cells from pancreas detect this
2. Alpha cells release glucagon into the blood
3. Glucagon binds to complimentary receptors on liver cells
4. Enzymes are activated in cells stimulate glycogenolysis and gluconeognesis.
5. More glucose secreted into the blood

Question 5

Define homeostasis

Answer 5

The maintenance of constant internal environment despite changes in the external environment

Question 6

Describe the action of adrenaline in the regulation of blood glucose

Question 7

Describe the 2nd messenger model in the process of glycogenolyis

Question 8

Describe the causes and treatments of type 1 diabetes

Answer 8

Cause - inability to produce insulin

Treatment - monitor blood glucose conc regularly using biosensor, inject insulin.

Question 9

Describe the causes and treatments of type 2 diabetes

Answer 9

Cause - resistance to insulin, obesity and poor diet

Treatment - regulation of diet, exercise, medication such as metaformin

Question 10

Required Practical 11:

Answer 10

1. Make up several glucose suctions of different concentrations using serial dilution
2. Use equal volume of glucose solution and quantitative Benedict’s reagent and stir gently.
3. Heat in water bath
4. Measure absorbance of each solution using a colorimeter
5. Calibrate (zero) colorimeter between each reading using pure water
6. Plot a calibration curve of concentration of glucose on x-axis against absorbance on your-axis
7. Find concentration of an unknown sample from the calibration curve

Question 11

Define negative feedback

Answer 11

A change from a norm or set point is detected = mechanisms used to return to the set point

Question 12

Define positive feedback

Answer 12

Any change away from the norm creates more change = mechanism used for change.