Session 2- Energy Storage- Glycogen and Fat

Question 1

what tissues have an absolute requirement for glucose

Answer 1

red blood cells
neutrophils
innermost cells of kidney medulla
lens of the eye

Question 2

how is glycogen stored

Answer 2

in granules

Question 3

where is glycogen stored

Answer 3

muscle-300g

liver - 100g

Question 4

what is the primer of glycogen that it originates from

Answer 4

glycogenin which is at the centre

Question 5

how is glycogen synthesised

Answer 5

glucose + ATP = glucose-6-phosphate + ADP
Hexokinase

Glucose-6-phosphate = glucose-1-phosphate
phosphoglucomutase

glucose-1-phosphate + UTP + H20 = UDP-Glucose + PPi
G1P uridyltransferase

glycogen (n resisdues) + UDP-glucose = glycogen (n+1 residues) + UDP 
         glygogen synthase (alpha 1-4 )or branching enzyme (alpha 1-6)

Question 6

glycogenolysis in the liver

Answer 6

glycogen (n residues) + Pi = glucose 1-phosphate = glycogen (n-1 resisdues)

enzyme: glycogen phosphorylase
debranching enzyme

glucose-1-phosphate = glucose-6-phosphate
enzyme: phosphoglucomutase
glucose-6-phosphate = glucose
released by liver into blood for use by other tissues

Question 7

glycogenolysis in the muscle

Answer 7

glycogen (n residues) + Pi = glucose 1-phosphate = glycogen (n-1 resisdues)

enzyme: glycogen phosphorylase
debranching enzyme

glucose-1-phosphate = glucose-6-phosphate
enzyme: phosphoglucomutase

glycolysis- used by muscle for energy production

lacks the enzyme glucose-6-phosphotase so G6P enters glycolysis for energy production

Question 8

von Gierke’s disease

Answer 8

glucose-6-phosphatase deficiency

CANT STORE GLYCOGEN

Question 9

McArdle’s disease

Answer 9

muscle glycogen phosphorylase deficiency

Question 10

after how long does gluconeogenesis occur

Answer 10

beyond around 8 hours of fasting

Question 11

what are the three main precursors of gluconeogenesis

Answer 11

lactate from the cori cycle
glycerol
amino acids

Question 12

what is the cori cycle

Answer 12

glucose is converted to glucose then into 2 lactates in the muscles then in the liver the two lactates are converted into glucose again

Question 13

why cant you make pyruvate from acetyl-CoA

Answer 13

it cant be converted because the pyruvate dehydrogenase reaction is irrversible

Question 14

where does gluconeogenesis occur

Answer 14

liver and kidney

Question 15

what are the key enzymes in gluconeogenesis

Answer 15

1) phosphoenopyruvate carboxylkinase (PEPCK)
2) Fructose 1,6 bisphosphate
3) glucose-6-phosphatase

Question 16

what are the major sites of control in gluconeogenesis

Answer 16

fructose 1,6-bisphosphate

PEPCK

Question 17

what does phosphoenopyruvate carboxykinase do

PEPCK

Answer 17

Oxaloacetate into phosphophenolpyruvate

Question 18

what does fructose 1,6 bisphosphatase do

Answer 18

fructose 1,6 bisphosphate into fructose 6-phosphate

Question 19

what does glucose-6-phosphatase

Answer 19

glucose 6-phosphate into glucose

Question 20

what does excess energy intake get converted into

Answer 20

triacylglycerol

Question 21

how are TAGs stored

Answer 21

in their anhydrous form because they are hydrophobic in adipose tissue

Question 22

what is lipogenesis

Answer 22

fatty acid synthesis
mainly in liver

glucose converted into pyruvate in cytoplasm

pyruvate enters mitochondria and forms acetyl-coA and OAA which condenses to form citrate

citrate take into cytoplasm and cleaved back into Acetyl-coA and OAA

acetyl-coA carboxylase produces manonlyl-coA from Acetyl-coA

fatty acid synthase complex builds fatty acids by sequenyial addition of 2 carbon units provided by manonlyl-coA

Question 23

what does fatty acid synthesis need

Answer 23

ATP NADPH

Question 24

what is lipolysis

Answer 24

fat mobilisation

triacylglyerol converted into fatty acids and glycerol by lipase

glycerol taken to liver and is utilised as carbon source for gluconeogenesis
fatty acids travel with albumin to muscle and other tisses- beta oxidation

Question 25

after 2 hours after feeding

Answer 25

glucose and fat available from gut - immediate metabolism supported by glucose - speed up growth and repair processes - make glycogen as rapidly as possible - increase fat stores

Question 26

2-10 hours after feeding

Answer 26

glucose and fats no longer being absorbed - maintain blood glucose by drawing on glycogen stores - support other metabolic activity with fatty acids released from stores - preserve blood glucose for brain

Question 27

no food for 8-10 hours

Answer 27

glycogen stores depleted - need to make more glucose for brain from amino acids, glycerol and lactate - continue to support other metabolism with fatty acids

Question 28

starvation

Answer 28

fatty acid metabolism produces ketone bodies brain becomes able to metabolism ketone bodies (reduces need for glucose)

Question 29

hypoglycaemia

Answer 29

blood glucose less that 3 mmol/L ``` CNS function impaired confusion weakness slurred speech staggering loss of consciousness ```

Question 30

hyoerglycaemia

Answer 30

chronic blood glucose >7 mmol/L leads to damage of: -nerves, blood vessels, kidney and retina

Question 31

what is the appropriate range of blood glucose

Answer 31

3.3 - 6.0 mmol/L

Question 32

why must blood glucose be kept between the normal range - brain

Answer 32

rate of glucose uptake by CNS determined by blood glucose CNS

Question 33

metabolic acidosis

Answer 33

an abnormal primary process or condition leading to an increase in fixed acids in the blood ketoacidosis lactic acidosis

Question 34

respiratory acidosis

Answer 34

a primary acid-base disorder in which arterial pCO2 rises to a level higher than expected

Question 35

oral glucose test

Answer 35

standard dose of glucose ingested by mouth after 8 hour fast venous plasma glucose checked at time of administration and @ 30 min intervals

Question 36

what diseases can a heel pick diagnose Peter Came Home So Cold

Answer 36

``` phenylketonuria congenital hypothyroidism Homocystenuria Sickle cell disease Cystic fibrosis ```