BIOC192 Lecture 29 - Fatty Acid Oxidation

Question 1

what is the preferred fuel for most tissues?

Answer 1

fatty acids

Question 2

what type of muscle cell uses fatty acids?

Answer 2

red muscle cells

Question 3

what are the 3 characteristics of red muscle cells?

Answer 3

1) long distance running
2) slow twitch
3) fats as fuel

Question 4

does red muscle use anaerobic and aerobic processes ?

Answer 4

aerobic energy

Question 5

what is the primary energy reserve?

Answer 5

fat/fatty acids

Question 6

how are fats stored in the human body?

Answer 6

stored as TAGs - triacylglycerols

Question 7

what is the range of how much percent of body weight an be stored fatty acids?

Answer 7

5 to 25% of mammalian body weight

Question 8

why is fuel stored as fats?

Answer 8

fatty acids are more reduced than carbohydrates this means that more energy is released when oxidised in pathways

Question 9

how many percent is stored carbohydrates (glycogen)?

Answer 9

approximately 2/3 water

Question 10

where are triacylglycerols stored?

Answer 10

in the adipose tissue

Question 11

are free fatty acids hydrophilic or hydrophobic?

Answer 11

hydrophobic

Question 12

what is the function of the albumin protein?

Answer 12

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

Question 13

how does the fatty acids deliver across the cell fuel?

Answer 13

has to cross the cell membrane

Question 14

what is fatty acid activation?

Answer 14

-fatty acids are activated for oxidation before the fatty acid enter the mitochondria

Question 15

how are the fatty acids activated?

Answer 15

activated by attachment to CoA making fatty acyl-CoA

Question 16

what is the energy expenditure for fatty acid activation?

Answer 16

energy hydrolysis of ATP as 2 ATP are spent

Question 17

what is fatty acyl-CoA?

Answer 17

CoA attached to a carbon chain of any length

Question 18

what is acetyl-CoA?

Answer 18

a two-carbon chain

Question 19

where does the oxidation of fatty acids occur?

Answer 19

occurs in the mitochondrial matrix

Question 20

what is transport of fatty acids into the mitochondria matrix?

Answer 20

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

Question 21

what is the carnitine acyl-transferase reaction?

Answer 21

the exchange of CoA and carnitine on a fatty acid in a reversible reaction

Question 22

what does beta-oxidation only work for?

Answer 22

only uses fatty acids with an even number of carbons that are saturated (have no double bonds)

Question 23

is ATP made in beta-oxidation?

Answer 23

no ATP is made in beta-oxidation

Question 24

what coenzymes is the energy released in beta-oxidation transferred to?

Answer 24

coenzymes NAD and FAD

Question 25

what does beta oxidation cut?

Answer 25

cuts carbon chain in 2C pieces like a cycle

Question 26

what is the product of beta-oxidation?

Answer 26

acteyl-CoA

Question 27

what happens to the product of beta-oxidation?

Answer 27

acetyl-CoA is further oxidised in the citric acid cycle

Question 28

what type of reactions are each of the 3 reactions of beta-oxidation?

Answer 28

• reaction 1 = oxidation
• reaction 2 = hydration
• reaction 3 = oxidation

Question 29

what happens in reaction 4 of beta-oxidation?

Answer 29

cleavage of acyl-CoA is released

- 2C shorter fatty acyl-CoA enters the next round

Question 30

what is the formula for the number of rounds of oxidation?

Answer 30

number of rounds = n(C)/2 - 1