Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > Fatty Acid Metabolism > Flashcards

Fatty Acid Metabolism Flashcards

1
Q

what are the functions of fatty acids?

A

energy storage and production
structural components of membranes
hormones derived from
carboxylic acid at one end & long C chain
saturated (no double bonds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a saturated fatty acid?

A

with no double bond present in long C chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is an unsaturated fatty acid?

A

with one or more double bonds present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is a lipid?

A

fatty acids conjugated with glycerol
linked to glycerol by ester bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are esters?

A

linkages formed between a carboxylic acid and a alcohol group by the loss of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is glycerol?

A

3C
3 OH groups
common lipid skeleton

present in most lipids in body
not easy to transport around body
storage molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

is triacylglyerol an energy source?

A

all tissues (not brain) can oxidise fatty acids to produce energy

TAG not used until glucose supplies are low
fatty acids transported in the blood complexed with serum albumin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

equation of TAG breakdown?

A

TAG + 3h2o —> glycerol + 3 fatty acids

catalysed by triacylglycerol lipase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the steps in the oxidation of fatty acids?

A

step 1: free fatty acids I the systole are activated forming fatty acid acetyl coA
step 2: falty acyl coA uptake into mitochondria
step 3: B-oxidation pathway in mitochondrial matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain step 1

A

fatty acid activation

reacts with ATP & alpha phosphorus

intermediate with fatty acid AMP group attached via ester linkage

phosphates released as pyrophosphates -> phosphates

coA displaced, attach to fatty acid to make phosphodiester between
produces AMP

all at the cost of 2 ATPs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

explain step 2

A

fatty acyl coA uptake by mitochondria

carnitine shuffle used to transport fatty acylcoA from cytoplasm to mitochondrial matrix

fatty coA reacts, add carnitine
allows transfer through
regenerate fatty acyl coA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

explain step 3

A

B oxidation of fatty acids I mitochondria
C beta is oxidised

takes 2C off at a time and keeps going until nothing left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

reaction 1 of step 3

A
  • H removed from alpha and beta C by acyl coA dehydrogenase
  • has FAD coenzyme
  • e- delivered to coenzyme Q in transport chain
  • take bond between alpha and beta c oxidase and make a double bond
  • FADH2 used to make ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

reaction 2 of step 3

A
  • hydration of double bond
  • produces hydroxyacyl coA
  • hydrate the double bond, add -OH group on beta carbon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

reaction 3 of step 3

A
  • C-OH oxidised to C=O
  • NADH formed oxidised by e- transport chain to produce ATP
  • oxidise alcohol to form ketone, forming NAD
  • changes beta C to ketone C
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

reaction 4 of step 3

A
  • CoASH attacks beta C to produce acetyl coA and fatty acyl coA which is 2C smaller
  • acetyl coA oxidised by citric acid cycle
  • shortened fatty acid by 2C

process repeats until all of molecule converted

17
Q

what is the ATP yield from oxidation of palmitate?

A

16 C
cost of 2 ATP
so 7 rounds of B-oxidation yields

8 acetyl coA - 8x10 ATP
7 NADH - 7x2.5 ATP
7 FADH2 - 7x1.5 ATP
= 108 ATP
so net yield of 106 ATP

18
Q

Glyoxylate cycle

A

plants, fungi and bacteria convert acetyl coA to sugars through the glyoxylate cycle

happens in glyoxysomes
modified version of the citric acid cycle

19
Q

equation of glyoxylate cycle

A

2 acetyl coA —> malate —> oxaloacetate

20
Q

fatty acid synthesis

A

occurs in cytoplasm using different carrier
different coenzymes
different C2 donor/product

21
Q

where does it occur?

A

in the cytoplasm
delivers acetyl coA from mitochondria to the cytoplasm

provides acetyl coA and NADPH in the cytoplasm

22
Q

step 1 of synthesis

A

synthesis of malonyl coA

energy to form C-C bonds supplied indirectly by synthesising malonyl coA using ATP and CO2

catalysed by acetyl coA carboxylase
reacts with carbon dioxide

23
Q

reaction 1 of synthesis

A

acetyl group acted using malonyl coA as donor
loss of CO2 drives reaction

malonyl coA synthesised by carboxylation of acetyl coA
2C longer

24
Q

reaction 1 equation

A

acetyl coA + CO2 + ATP —> malonyl CoA + ADP + Pi

25
Q

reaction 2 of synthesis

A

c=o group on C3 reduced to C-OH by NADPH
ketone reduced to alcohol

26
Q

reaction 3 of synthesis

A

dehydration
generates double bond between alpha and beta carbon

27
Q

reaction 4 of synthesis

A

reduction of double bond to single bond

can now re-enter the process
keep adding 2C until long enough to release

28
Q

what is fatty acid synthesis carried out by?

A

single multifunctional enzyme
exists as a dimer
all done internally so makes it quicker

29
Q

how is acetyl coA carboxylase tightly regulated?

A

inhibited by phosphorylation
AMP is a major kinase
once phosphorylated it is turned off
kinase activated by AMP from lack of ATP

insulin favours fatty acid synthesis by activating a phosphate that dephosphorylated acetyl coA carboxylase

Biochemistry (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions