BIOC192 Lecture 29 - Fatty Acid Oxidation Flashcards
what is the preferred fuel for most tissues?
fatty acids
what type of muscle cell uses fatty acids?
red muscle cells
what are the 3 characteristics of red muscle cells?
1) long distance running
2) slow twitch
3) fats as fuel
does red muscle use anaerobic and aerobic processes ?
aerobic energy
what is the primary energy reserve?
fat/fatty acids
how are fats stored in the human body?
stored as TAGs - triacylglycerols
what is the range of how much percent of body weight an be stored fatty acids?
5 to 25% of mammalian body weight
why is fuel stored as fats?
fatty acids are more reduced than carbohydrates this means that more energy is released when oxidised in pathways
how many percent is stored carbohydrates (glycogen)?
approximately 2/3 water
where are triacylglycerols stored?
in the adipose tissue
are free fatty acids hydrophilic or hydrophobic?
hydrophobic
what is the function of the albumin protein?
albumin protein is needed to bind with the free fatty acid because the free fatty acid is hydrophobic and therefore it can not dissolve in the blood. The hydrophobic residues on the outside of the albumin-FFA allow the free fatty acid to be transported in the blood in the hydrophobic pockets of the albumin
how does the fatty acids deliver across the cell fuel?
has to cross the cell membrane
what is fatty acid activation?
-fatty acids are activated for oxidation before the fatty acid enter the mitochondria
how are the fatty acids activated?
activated by attachment to CoA making fatty acyl-CoA
what is the energy expenditure for fatty acid activation?
energy hydrolysis of ATP as 2 ATP are spent
what is fatty acyl-CoA?
CoA attached to a carbon chain of any length
what is acetyl-CoA?
a two-carbon chain
where does the oxidation of fatty acids occur?
occurs in the mitochondrial matrix
what is transport of fatty acids into the mitochondria matrix?
the fatty acyl-CoA must pass through 2 membranes
1) outer membrane -fatty acyl-CoA carrier
2) inner membrane - requires the conversion to fatty acyl-carnitine
what is the carnitine acyl-transferase reaction?
the exchange of CoA and carnitine on a fatty acid in a reversible reaction
what does beta-oxidation only work for?
only uses fatty acids with an even number of carbons that are saturated (have no double bonds)
is ATP made in beta-oxidation?
no ATP is made in beta-oxidation
what coenzymes is the energy released in beta-oxidation transferred to?
coenzymes NAD and FAD
what does beta oxidation cut?
cuts carbon chain in 2C pieces like a cycle
what is the product of beta-oxidation?
acteyl-CoA
what happens to the product of beta-oxidation?
acetyl-CoA is further oxidised in the citric acid cycle
what type of reactions are each of the 3 reactions of beta-oxidation?
- reaction 1 = oxidation
- reaction 2 = hydration
- reaction 3 = oxidation
what happens in reaction 4 of beta-oxidation?
cleavage of acyl-CoA is released
- 2C shorter fatty acyl-CoA enters the next round
what is the formula for the number of rounds of oxidation?
number of rounds = n(C)/2 - 1
