Control of Blood Glucose and Diabetes Flashcards
Why can hypo/hyperglycaemia kill cells?
It changes water potential of cells away from optimum so cells burst or shrink.
Give 2 needs for glucose.
Respiration
Synthesis of other biomolecules
Give 3 factors that can increase glucose concentration.
Diet
Hydrolysis of glycogen
Gluconeogenesis
What is the pancreas?
A large gland secreting hormones and enzymes
What are 2 functions of isles of Langerhans?
Act as receptors and endocrine cells
What do alpha cells secrete?
Glucagon
Compare the size of alpha and beta cells.
Alpha cells bigger, beta cells smaller
What do alpha cells detect?
Low glucose concentration
What do beta cells detect?
High glucose concentration
What do beta cells secrete?
Insulin
What is glycogenesis?
Conversion of glucose into glycogen
What is glycogenolysis?
Hydrolysis of glycogen into glucose
What is gluconeogenesis?
Synthesis of new glucose molecules from sources of biomolecule
Describe the conditions needed for glycogenesis.
Occurs when blood glucose concentration is higher than normal, so glucose is converted to glycogen
What conditions are needed for glycogenolysis?
Low blood glucose concentration, so glycogen is hydrolysed to release glucose into the blood
What conditions are needed for gluconeogenesis?
Glucose synthesised from alternative sources when glycogen levels are low.
What is lipogenesis?
Glucose converted to lipids
Describe the process of lowering blood glucose concentration.
- Beta cells detect high blood glucose concentration
- They secrete insulin which binds to muscle and receptor cells.
- Glucose uptake in cells, glycogenesis and lipogenesis increased
- Glucose removed from cells
State 3 things that insulin causes to happen in the body to lower blood glucose concentration.
Increased lipogenesis
Increased Glycogenesis
Increased lipogenesis
State 2 things that glucagon causes to happen in the body to raise blood glucose concentration.
Increased glycogenolysis
Increased gluconeogenesis
Describe the process of raising blood glucose concentration.
Name the enzyme involved and what this enzyme catalyses.
- Alpha cells detect drop in blood glucose concentration
- They secrete glucagon which binds to receptors and muscle cells.
- Receptor activates membrane bound enzyme adenylate cyclase.
- Adenylate cyclase catalyses conversion of ATP to cAMP.
- cAMP activates kinase.
- Kinase activates enzymes that cause glycogenolysis
- This raises blood glucose concentration.
What does adenylate cyclase catalyse?
Conversion of ATP to cyclic adenosine monophosphate (cAMP)
What protein does cAMP activate?
Kinase
Name 2 ways that adrenaline can raise glucose concentration.
By attaching to protein receptors on cell surface membranes of target cells
Activating enzymes that cause breakdown of glycogen to glucose in the liver
What is type 1 diabetes?
An autoimmune disease which causes destruction of beta cells, so no insulin is produced.
How is type 1 diabetes treated?
With insulin injections and control of diet
What is type 2 diabetes?
Insulin is produced but receptors in target cells no longer respond
Give 4 risk factors for type 2 diabetes.
Poor diet
Low exercise
Genes
Obesity
Explain some symptoms of diabetes.
High thirst due to loss of water from cells
Excess water in blood due to loss from cells, leading to excess urination
Tiredness due to loss of glucose in blood
Muscle wasting due to increased gluconeogenesis
