2. control of blood glucose conc

Question 1

what affects blood glucose conc

Answer 1

rises after eating food containing carbs

decreases after exercise (more glucose is used in respiration to release energy)

Question 2

Beta cells

Answer 2

secrete hormone insulin

Question 3

alpha cells

Answer 3

secrete hormone glucagon

Question 4

alpha and beta cells are found

Answer 4

on the pancreas (islets of langerhans)

Question 5

Insulin action

Answer 5

(lowers blood glucose conc when its too high)

1. binds to specific receptors on cell membrane of liver cells and muscle cells
2. increases permeability of muscle cell membranes to glucose so cells take up more glucose (increases number of channel proteins)
3. GLYCOGENESIS - activates enzymes in the liver and muscle cells that convert glucose into glycogen (which is stored in cytoplasm as an energy source)
4. increases rate of respiration of glucose in cells

Question 6

Glucagon action

Answer 6

(increases blood glucose conc when too low)

1. binds to specific receptors on cell membrane of liver cells
2. GLYCOGENOLYSIS activates enzyme in liver that break down glycogen into glucose
3. GLUCONEOGENESIS activates enzymes involved in formation of glucose from non-carbs e.g. glycerol and amino acids
4. decreases rate of respiration of glucose in cells

Question 7

hormone action

Answer 7

slower - travel through blood
last for longer - not broke down as quick as neurotransmitters
(than nerve impulses)

Question 8

Insulin and glucose transporters

Answer 8

1. skeletal and cardia muscle cells contain channel protein which is a glucose transporter
2. insulin levels low channel protein is stored in vesicles in cytoplasm of cells
3. insulin binds to receptors triggers movement of channel protein to membrane
4. glucose can then be transported into the cell through the channel protein by facilitated diffusion

Question 9

Adrenaline

Answer 9

1. secreted from adrenal glands when low conc of glucose in blood
2. binds to receptors on liver cells
3. activates GLYOGENOLYSIS
4. inhibits GLYCOGENESIS
5. activates glucagon secretion and inhibits insulin secretion

Question 10

second messenger adrenaline or glucagon

Answer 10

1. bind to receptors
2. activate enzyme adenylate cyclase
3. converts ATP into second messenger - cyclic AMP (cAMP)
4. activates enzyme protein kinase A which activates the break down of glycogen into glucose GLYCOGENOLYSIS

Question 11

Type 1 diabetes

Answer 11

1. immune system attacks b cells. cant produce insulin
2. genetic predisposition or triggered by viral infection
3. after eating blood glucose rises and stays high (hyperglycaemia) kidneys cant reabsorb all glucose some into urine.
4. can result in death
5. insulin therapy - regular insulin injections (need to be careful. don’t want hypoglycaemia)
6. eating regularly and controlling simple carb intake helps avoid sudden rise

Question 12

Type II diabetes

Answer 12

1. usually later in life.
2. linked with obesity / previous family members having it. risk factors - lack of exercise, age, poor diet
3. B cells dont produce enough insulin or receptors dont respond properly to insulin.
4. cells dont take up enough glucose = higher than normal
5. treatment - healthy balanced diet, losing weight, regular exercise. glucose lowering medication. insulin injections