6.4 .2 Flashcards
Name the factors that affect blood glucose concentration
-amount of carbohydrate digested from diet
-rate of glycogenolysis
-rate of gluconeogenesis
Define glycogenesis
Liver converts glucose into the storage polymer glycogen
Define glycogenolysis
liver hydrolyses glycogen into glucose which can diffuse into blood
Define Gluconeogenesis
Liver converts glycerol and amino acids into glucose
Outline the role of glucagon when blood glucose concentration decreases
- a-cells in Islets of Langerhans in pancreas detect decrease and secret glucagon into bloodstream.
- Glucagon bonds to surface receptors on liver cells and activates enzymes for glycogenolysis and gluconeogenesis
- Glucose diffuse from liver into bloodstream
Outline the role of adrenaline when blood glucose concentration decreases
- Adrenal glands produce adrenaline. It binds to surface receptors on liver cells and activates enzymes for glycogenolysis
- Glucose diffuses from liver into bloodstream
Outline what happens when blood glucose concentration increases
- B-cells in Islets of Langerhans in pancreas detect increase and secrete insulin into bloodstream
- Insulin binds to surface receptors on target cells to:
a) increase cellular glucose uptake
b) activate enzymes for glycogenesis (liver and muscles)
c) stimulate adipose tissue to synthesise fat
Describe how insulin leads to a decrease in blood glucose concentration
-increases permeability of cells to glucose
-increases glucose concentration gradient
- triggers inhibition of enzymes for glycogenolysis
How does insulin increase permeability of cells to glucose
- increases number of glucose carrier proteins
- triggers conformational change which opens glucose carrier proteins
How does insulin increase the glucose concentration gradient
-activates enzymes for glycogenesis in liver and muscles
- stimulates fat synthesis in adipose tissue
Use the secondary messenger model to explain how glucagon and adrenaline work
- Hormone-receptor complex forms
- Conformational change to receptor activates G-protein
- activates adenylate cyclase which converts ATP to cyclic AMP (cAMP)
- cAMP activates protein kinase A pathway
- Results in glycogenolysis
Explain the cause of Type 1 diabetes and how it can be controlled
Body cannot produce insulin.
Treat by injecting insulin
Explain the causes of Type 2 diabetes and how it can be controlled
Glycoprotein receptors are damaged or become less responsive to insulin
Strong positive correlation with poor diet/ obesity
Treat by controlling diet and exercise regime
Name some signs and symptoms of diabetes
-high blood glucose conc
-glucose in urine
Outline how colorimetry could be used to identify the glucose concentration in a sample
- Benedicts test on solutions of known glucose concentration. Use colorimeter to record absorbance
- Plot calibration curve: absorbance (y axis), glucose concentration (x axis)
- Benedicts test on unknown sample. Use calibration curve3 to read glucose concentration at its absorbance value
