WEEK 4 Flashcards
describe the fate of fatty acids and glycerol (x2)
1) glycerol is carried in the blood dissolved as it is soluble in the plasma as it has three OH groups attached
2) free fatty acids are carried in the blood attached to the protein albumin as they are not soluble in the plasma
how do fatty acids be transported to the muscle
fats moves through the blood via lipoproteins (triglycerides)
why do fatty acids need transporters to travel through
- in skeletal muscle the fatty acid is transported across the membrane via proteins
- fatty acid binding protein
- fatty acid transclose
describe the transport of fatty acids to the mitochondria (x3)
- in the skeletal muscle the fatty acid is transported across the membrane via proteins
- once inside the cells, the fatty acid must be transported into the mitochondria
- a cytosolic fatty acid binding protein transports the fatty acid to the outer membrane of the mitochondria
describe stearic acid and what equation is it ( an example of beta oxidation)
- common dietary fat
- found mostly in animal fats
- found in some plants
C18H36O2
how much ATP is produced from 1 molecule of stearic acid
3 ATP
list the summary of lipid metabolism ( 1-7)
1) breakdown of triglycerides to free fatty acids
2) transport of free fatty acids in the blood (attached to albumin which is the main protein in blood)
3) uptake of free fatty acids for catabolism
4) preparation of free fatty acids from blood to muscle
5) entry of activated. fatty acids into the muscle mitochondria
6) breakdown of fatty acids to acetyl- coa via oxidation and the production of NADH and FADH2
7) coupled oxidation in the citric acid cycle and electron transport chain
describe ketone bodies
- a fat derived fuel
ketones bodies:
- acetone
- acetotacetate
- can cross the blood brain barrier to be used as fuel for the brain
why do we produce ketone bodies?
x3)
- pyruvate is necessary for formation of the citric acid cycle intermediates via this reaction
- if glucose intake decreases, then not enough pyruvate is produced to maintain the citric acid cycle intermediates
- therefore excess acetyl coa is converted to ketone bodies
what is the 3 step process of ketogenesis
1) acetyl coa > acetoacetly coa
2) acetoacetyl coa + acetyl coa > HMG- coa
3) HMG- coa > acetotacetate + acetyl coa
acetoatate + NADH > hydroybutyrate + NAD
describe ketone body oxidation
oxidised in aerobic tissues such as muscle, heart and brain
why do diabetics produce ketone bodies? ( x3)
- high blood sugar
- reduced uptake into the cell
- cell takes on a starvation mode
describe fatty acid synthesis
- excess formation of the acetyl coa from glucose metabolism is used to make fatty acids that are then stored as triglycerides
fatty acid synthesis is the reverse of oxidation except 4 major differences
what are they?
1) fatty acid bio synthesis occurs in the cytoplasm not the mitochondria as with oxidation
2) no co enzyme involved rather acetyl carrier proteins takes its place
3) fatty acids bio synthesis carried out by one multi enzyme complex called fatty acid synthase
4) electron carriers are not NADH nor FADH like with oxidation.
describe the amino acid pool (x3)
- primarily used for protein synthesis
- also used for fuel
- constant turnover of amino acids into the muscle
what are the 2 major stages of catabolism of amino acids
1- the amino acid must lose the nitrogen atom
2- the resulting carbon skeletons enter into specific energy yielding pathways
describe oxidative deamination ( x4)
- amino groups need to be taken off the amino acid
- ammonia is toxic so must be excreted from the body
- ammonium ion is released from the exercising muscle
- the production of ammonium ion is proportional to exercise intensity
describe glutamine
- excess glutamate and ammonium ion can be converted to glutamine
- is an important fuel for the immune system and digestive system
what happens to deaminated amino acids
after the amino groups are removed they turn into carbon skeletons
how do we get rid of toxic ammonia in our bodies ( x3)
- can be stored temporarily within the molecules of glutamate and glutamine
- eventually needs to be excreted in the urea
- urea takes place in the liver
define gluconeogensis and describe the livers function in this
def= blood glucose must be maintained for brain function
- liver releases 125-175mg a min
- liver may hold 70g of glycogen when fed
list the non- carbohydrate precursors
- amino acids
- glycerol
- lactate
- propionic acid
describe the cori cycle ( x4)
- pyruvate is a 3 carbon molecule and therefore needs 2 to form glucose
- oxaloacetate îs a 4 molecule
- 1 carbon is lost to form 3 carbon molecules
- therefore they need 2 to form 1 glucose
what is glycogenolysis
glycogen breakdown
describe glycogen synthesis
1-2 hours of vigorous activity will deplete the bodies store of glycogen
- 1 gram of glycogen stores= 3 grams of water
