Regulation Of Blood Glucose Concentration

Question 1

What conversion regulates blood glucose concentration

Answer 1

Liver converts between glycogen and glucose

Question 2

3 processes within the liver when insulin and glucagon bind to membranes of liver cells

Answer 2

Glycogenesis
Glycogenolysis
Gluconeogenesis

Question 3

What is glycogenesis

Answer 3

Synthesis of glucose -> glycogen

Question 4

How is glycogenesis triggered

Answer 4

Insulin detects increased blood glucose concentration

Question 5

Which processes are for increased/ decreased blood glucose concentration

Answer 5

Increased = glycogenesis glucose -> glycogen
Decreased = glycogenolysis glycogen -> glucose

Question 6

How does glycogenesis work

Answer 6

Synthesises glycogen by removing glucose molecules form bloodstream which decreases blood glucose concentration

Question 7

What is glycogen

Answer 7

Compact and efficient carbohydrate storage molecule

Question 8

What is glycogenolysis

Answer 8

Glycogen -> glucose

Question 9

How does glycogenolysis work

Answer 9

Glucagon triggers reaction
1) Glucagon detects decreased blood glucose concentration
2) Activates enzymes within the liver to breakdown glycogen molecules into glucose
3) Glycogen releases more glucose molecules to bloodstream which increases the blood glucose concentration back to normal

Question 10

What does gluconeogenesis mean

Answer 10

Gluconeogenesis is synthesising non-carbohydrate molecules -> glucose

Question 11

How does gluconeogenesis work

Answer 11

1) Glucagon triggers enzymes in liver to convert molecules into glucose (e.g. fatty acids, amino acids -> glucose)
2) Glucose molecules released into bloodstream which increases the blood glucose concentration to normal

Question 12

3 ways glucose can enter the bloodstream

Answer 12

Absorption = digestion in gut
Hydrolysis = of glycogen
Non-carbohydrates converted to glucose

Question 13

What hormones control glucose concenration

Answer 13

Insulin and glucagon

Question 14

What organ regulates blood glucose

Answer 14

Pancreas

Question 15

What does the pancreas produce to maintain blood glucose concentration

Answer 15

Enzymes - protease, amylase, lipase - for digestion
Hormones - insulin and glucagon - regulating bgc

Question 16

How is blood glucose concentration regulated using hormones in the pancreas

Answer 16

1) Adrenaline (hormone) approaches transmembrane protein
2) Adrenaline fuses to receptor changing shape of the transmembranes active site forming an adrenaline-receptor complex - this stimulates adenyl cyclase (an enzyme) to be activated in the membrane
3) The activated adenyl cyclase converts ATP to cyclic AMP which acts as a second messenger
4) The cAMP changes the shape of activates protein kinase enzyme
5) The active protein kinase enzyme catalyses the conversion of glycogen to glucose

Question 17

What is the pancreas made up of

Answer 17

Islets of Langerhans which are made up of alpha cells and beta cells

Question 18

What do alpha and beta cells produce

Answer 18

Alpha cells = glucagon
Beta cells = insulin

Question 19

What happens when blood glucose concentration rises too much or too low and how

Answer 19

Glucose provides energy to need to maintain concentration
Too low = cells deprives of energy and die, brain cells especially sensitive as they can only respire glucose
Too high = lowers water potential of blood creating osmotic problems, dehydrate

Question 20

Blood glucose sources

Answer 20

1) Diet = absorbed form carbohydrates (starch, maltose, lactose, sucrose
2) Hydrolysis in small intestine of glycogen (glycogenolysis)
3) gluconeogenesis = production of glucose from other molecules

Question 21

How is glucose concentration detected in pancreas

Answer 21

Beta cells of islets of Langerhans have receptors to detect when bgc too high
Secrete hormone insulin directly into blood plasma

Question 22

What occurs when insulin binds to receptors on cell surface membranes of glycoproteins

Answer 22

1) Changes tertiary structure of glucose transporter carrier proteins = allowing more glucose into cells by facilitated diffusion
2) increase number of carrier proteins that transport glucose in cell surface membrane
3) activates enzymes to convert glucose -> glycogen and fat

Question 23

Blood glucose concentration lowered how

Answer 23

Increase rate of:
1) absorption of glucose in cells
2) respiratory rate of cells (use more glucose, increasing uptake from blood)
3) converstion of glucose into glycogen in cells of liver and musckes
4) converstion of glucose -> fat

Question 24

What does alpha cells detect

Answer 24

Fall in bgc

Question 25

How do alpha cells respond to fall in blood glucose

Answer 25

Secrete glucagon directly into blood plasm

Question 26

How does glucagon raise blood gc

Answer 26

1) Attach to specific protein receptors on cell-surface membrane of liver cells
2) Activate enzymes that convert glycogen to glucose
3) Activate enzymes that convert amino acids and glycerol -> glucose (gluconeogenesis)

Question 27

Does adrenaline raise or lower bgc

Answer 27

Raise

Question 28

How does adrenaline raise bgc

Answer 28

Attaches to protein receptors on cell-surface membrane of target cells
Activates enzymes to breakdown glycogen -> glucose in the liver

Question 29

Describe what occurs if blood glucose concentration rises (hormones)

Answer 29

1) Detected by beta cells in pancreas which produces insulin
2) insulin will either:
-increase cellular respiration
-conversion of glucose -> glycogen
-converstion of glucose -> fat
-absorption of glucose -> cells
3) BGC falls back to optimum

Question 30

Describe what occurs when bgc falls

Answer 30

1) Detected by alpha cells in pancrease to produce glucagon
2) glucagon either:
-converts glycogen to glucose
-converts amino acids to glucose
3) back to optimum
OR
2) uncontrolled quantity of glucose enters from intestine
3) BGC rises back to optimum