lecture 11: fatty acid syntghesis beta oxidation Flashcards

1
Q

what is lipolysis

A

, triglycerides must first be broken down by hydrolysis into their two principal components, fatty acids and glycerol. This process, called lipolysis, takes place in the cytoplasm.

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2
Q

where does lipplysis occur

A

cytosol

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3
Q

what are the two hormones for regulation of lipolysis

A

glucagon

epinephrine

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4
Q

what is the effect of glucagon and epinephrine on the adipose tissie

A

increased trigylceride mobiliazition by activating the hormone sensitive lipase

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5
Q

what is the effect of epinephrine and glucagon on FA OXIDATION

A

it increases fatty acid tissues execpt the CNS and RBC

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6
Q

where is fatty acids built

A

cytosol

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7
Q

what is it called when you build a fatty acid

A

fatty acid synthesis

fatty acid biosynthesis

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8
Q

what is the trigger to start the build up of fatty acids (precursor)

A

acetyl coa

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9
Q

why is acetyl coa (where is it seen)

A

made from pyruvate and can go to the kreb cycle for energy
can go to form cholestterol
can be used to form fatty acids in the cytosol

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10
Q

can acetyl coa form fatty acids start in the mtiochondira

A

no , it needs to esceape the mtio and make the fatty acids i nthe cytsol of the cell

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11
Q

true or false: acetyl coa has a slight deviateion from tthe kreb cycle in order to form fatty acids

A

true

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12
Q

what is the first step acetyl coa must do in order to form a fatty acid

A

mustt merge with oxaloacetate to form citrate

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13
Q

will acetyl coa form citrate and aALWAYS leave the kreb cycle to form fatty acids

A

no

onyl when there is a need to form fatty acids

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14
Q

does actyle coa mix with oaxlo and form citrate in the mito or the cytsol

A

in the matrix

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15
Q

how deos citrate exit the mitochondira

A

needs a shuttle CITRATE SHUTTLE

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16
Q

TRue otr false; citrate can. exit the mitochondira easily (diffusion)

A

false it needs the citrate shuttle

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17
Q

what is the function of of the citrate shuttle

A

allows citrate to move past the mitochondria and into the cytosol

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18
Q

true or false: once citrate enters the cytsol, there is a reverese reaciton to turn it back into acetyl coa

A

true

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19
Q

why do we do the reverse reaction

A

there is no transporter to allow acetyl coa to go out of the memrbane

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20
Q

true or falseL acetyl coa is is hydrophillic and can easily pass through membvraen

A

false it is hydrophobic and needs a carrier to getit through the membrane

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21
Q

once citrate enters the cytsol, what reaction happens

A

citrate gets split back into acetyl coa and oxaloacetate (needs atp to get this reaction started)

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22
Q

does acetyl coa start as acetyl coa to form tvhe long chain fatty acyl coa

A

false it needs to get transformed into maloyn coa

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23
Q

what is the intiial fat compound made from actyl coa

A

malonyl coa (carbons in it that will add onto the malnyl group to because a long carbon fat chain)

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24
Q

WHat is the final profuct of fatty acid syhtesis

A

fatty acyl coa

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25
Q

can fatty acyl coa be immediately borken down

A

fatty acyl coa

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26
Q

what is the primer of fatty acid synthesis

A

acetyl coa

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27
Q

what is the purpose of malonyn

A

allows the addition of two carbons units

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28
Q

the two carbons that are added to the acetyl coa from malonyl must be reduced by what

A

for every 2 carbon unit, it must be reduced by 2 NADPH

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29
Q

what is the reaction for the syntehsis of palmiteic acid (c16)

A

Acetyl coa (2C) + 7 Malyn COa +14 NADPH + 14 H gives yyou

Palmmited acid (16 C) + 7 CO2 + 14 NADP + 8Coa + 6 h20

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30
Q

how does fatty acid synthesis work (general)

A

the maloyn coa (the backbone) will keep added carbons to the chain to form the proper length that it is programed to do

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31
Q

how many nadh is needed for every 2 carbons

A

2 nadph

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32
Q

becsides acetyl coa, what is needed in adequate concentrations for fatty acid syhtesis

A

carbohydate availability

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33
Q

why is it important to have adewuate carb availability

A

glucose goes to pyruvate which will ctreate the acertyl coa needed for fatty acid synthesis

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34
Q

what are the 3 important cycles coonnected to fatty acid sythesis

A
  • glycolysis (need to make pyruvate)
  • pyruvate oxidation to make acetyl coa
  • kreb cycle to form the citrate
  • pentose phosphate pathway to form the NADPH
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35
Q

where does the NADPH for fatty citrate come from

A

PPP

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36
Q

where does glucose/pyruvate for the fatty acid synthesis come from

A

glycolysis

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37
Q

where does the acetyl coa/citrate come from for the fatty synthesis

A

kreb cycle

38
Q

why is glyvolysis important for fatty acid synthesis

A

need adequate presentation of the acetyl coa unitts to the cycle which are coming from glycoslysi (pyruvate oxidation)

39
Q

what stimulates fatty acid synthesis

A

INSULINE

40
Q

what enzyme allows malyn coa to form the fatty cid

A

fatty acid synthase

41
Q

in order to fatty acids to be oxidzed where do they need to travel to

A

the mitochondira

42
Q

true or false: fatty acids can easliy flow through the mitochondiron membrane

A

false they are hydrophbic therefore need a carrier

43
Q

how much energy is needed to push the fatty actl group through the membrane

A

2 atp (ATP goes toAMP)

44
Q

what is the reason that the long chain fatty acyl must go out of the cytosol and into mitp

A

must find its way back to the mitcohondira so it can be brolen down and deliver its products to the ETC and kreb cycle

45
Q

what must bind to the fatty acyl group to start fatty acid transport into the mitochondira

A

carnatine

46
Q

what does carnatine replace

A

replaced the Co a group in the fatty acyl

47
Q

true or false: carnatine is a protein found within the blood

A

false, it is found within the cytsol of a cell

48
Q

how does the carnatine attach to the fatty acyl group

A

it requires atp > amp to charge the reaction

49
Q

whwere is carnatine acetyltransferase 1 found

A

outer mitchondiral membrane

50
Q

whatt is the function of the carnatine actyl transferase 1 enzyme

A

binds the carnatine fatty acyl and pushes it into the intermembrane space

51
Q

what does the carnatine fatty acyl need to enter tthrough the inner mitochondiral memrbane

A

needs to have a tranport protein

52
Q

once the carnatine fatty acyl has travelled through the inner mithoncdira membrane, what enxyme is it faced iwht

A

carnitne actyltransferase 2

53
Q

what is the function of the carnatine acetyl transferate 2 in the matrix

A

dislodges the carnatine from the fatty acyl group and picks up a co-a floating in the matrix of the mitochondira
=acetyl coa rebinds witth thte fatty acyn group
=FATTY ACYL COA IS REFORMED INSIDE THE MITCHONDIRA

54
Q

whatt does the processs of fatty acid transportation do

A

transportes fatty acid from the cytsoll to the mitchondira

55
Q

what is needed to get the uptake of fatty acid into the cell

A

carnatine and the carnatine acetyltransferaase enxymes

56
Q

true or false: once carnatine is disloasged from the fatty acid it is degreaded

A

false, it will go back out to the cytsolto be bound again

57
Q

hwo can carnatine easily travek throu gh the mitchondira membrane

A

it has polar heads

58
Q

what happens to the carnatine actyl transferase 1 once it binds with carnatine

A

changes conformation and allows the long chain fatty acid to enter the intermembrane space to travel throug hthe transporter

59
Q

once the fatty acyl travels througj the inner memrbane of the mitchondira,does it still have its carnatine group attached

A

yes

60
Q

how is carnatine removef from the fatty actid

A

carnatine acetyl transferase 2

61
Q

what replaced the carnatine that is dislodged from the fatty acid and what is that fucntion

A

a coa group to regorm the fatyl acid group inside the memrbane

62
Q

explain the process of biosyhtesis of fats

A

1) acetyl coa is the primer (arrives from glycolysis and kreb cycle
2) acrtyl coa merges witth oxaloacetate to form citrate IN THE MITOCHONDRIA
3) citrate enters the cytsol through the citrate shuttle
4) once inside the cytosol, citrate splits back into actyl coa and oxaloaceate (requires ATP)
5) Acetyl coa is converted to malonyl coa (by ACETYL COA CARBOXYLASE0
6) Maloyn will add carbons to it 1 at a time by the enxyme fatty acid synthase (uses 2 nadph)
7) fatty is made

63
Q

what tis the enzyme that converts acetyl coa to malonyl coa

A

acetyl coa carbxoylase

64
Q

what is the enzyme that converts maloyn coa to the faty ACID (what allows you to add carbons )

A

fatty acid synthase

65
Q

what is the process of fatty acid transport from the cytsol to the mitochondira

A

1) fatty acid in the cytsol is bound with a coa group
2) ATP> AMP to prove energy to remove the coa group and bind carnatine
3) carnatine acetyl transferase enzyme 1 (in the outer mitochondrial membrane) binds carnatine, changes conformation and pulls the fatty acid with carnatine tp the intermembrane space
4) the fatty acid with carnatine travels through a transprot protein located i nthe inner mitochondrials membrane
5) carnatine actyltransferate 2 dislodged the carnatine protein and re atttached a coa groupo
=RE FORMED FATTY ACYL GROUP
6) Fatty acid can go and be oxideized and carnatine can reexit and be boudn to a new fatty acid

66
Q

where does fatty oxidattion (beta oxidation) occur

A

in the mitochondira

67
Q

why is beta oxidation in the mitchodnira

A

so the products made (NADH and FADH and Acetyl coa) can go and enter the kreb cycle and the ETC

68
Q

what is the prupose of beta oxidation

A

BREAKING down fatty acids from for energy

69
Q

what is the main sequential event for beta oxidation

A

newly formed fatty acid arrives (many carbons attached)
Series of chemical reactions converts the fatty acyl coa to:
acrtyl coa (2 carbon)
FADH2
NADH
>left with a 14 c chain that cna re go through the oxidation

70
Q

everytime you go through one cycle of beta oxidation, what do you form

A

1 NADH
1 FADH2
1 Acetyl coa

71
Q

where does the FADH2 and NADH from the beta oxidation go

A

to the ETC for ATP

72
Q

where does the acetyl coa formed form beta go

A

Kreb cycle to form more NADH AND FADH2 and then the ETC

73
Q

how many steps of beta oxidation are there

A

4 steps

74
Q

what is the formula for number of cycles of beta oxidation

A

(number of carbons/2) - 1

75
Q

give an example of calcualtion the number of cycles of palmitic acid

A

palmitic = 16 c
16 C/ 2= 8
8-1
=7

76
Q

how many carbons do you break off for ebvery cycle of beta

A

2 carbon (as acetyl coa)

77
Q

what is the 14 carbon called from palmatate

A

myriostol coa

78
Q

once you are left with a 2 carbon entity will it reenter into beta oxidation

A

no , it will be acetyl coa and will just enter the kreb cycel

79
Q

what are the 2 cofactors needed for beta oxidation

A

NAD gets reduced to NADh

FAD gets reduced to FADH2

80
Q

how many atp is made from 1 acetyl coa of beta

A

12 atp (because kreb makes 3 nadh = 3 atp, 2 fadh2= 2 atp and 1 atp from gtp)

81
Q

for each nadh procudes in beta, how many atp can be formed from ETC

A

3 atp

82
Q

for every FADH2 produced in beta, how many atp

A

2

83
Q

what are the 4 main reactions for beta

A

dehydration
hydration
dehydrogenation
thiolysis

84
Q

true or false: the chain will continue to break down (ie. beta will continue) until you are left with 0 carbons

A

false it will stop when you have 2 carbons left becausre that will be actyl coa

85
Q

true or false: the acetyl coa from beta is wasted

A

false it goes to kreb cycle for atp

86
Q

true or false: the acetyl coa from beta is wasted

A

false it goes to kreb cycle for atp

87
Q

why is there a net atp in beta of 129 and not 131

A

you lose two phosphates/2 atp to get the fatty acid into the mitochondira (ATP goes to AMP)`

88
Q

how many atp can be formed for a 16 carbon fatty acid

A

7 cycles

8 acetyl (8 acetyl x 12 atp) =96 atp
7 nadh (7 x 3 atp) = 21
7 FADH (7x 2 atp) = 14 

total: 131- 2 ATP TO GET FATTY IN MITOCHONDIRA
total net= 129 atp

89
Q

what is important to note in terms of oxygen for the brta oxidation

A

you need greater levels of xoygen to bind all the elctrons that are coming off of the FADH2 and NADH prduced from the beta

90
Q

the acetyl coa formed from the beta oxidation can only go to the kreb cycle?

A

no it can go to the kreb cycle but it can also develop ketone bodies

91
Q

how are ketone bodies rpoduced

A

by 2 acetyl coas