lecture 11: fatty acid syntghesis beta oxidation Flashcards
what is lipolysis
, 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.
where does lipplysis occur
cytosol
what are the two hormones for regulation of lipolysis
glucagon
epinephrine
what is the effect of glucagon and epinephrine on the adipose tissie
increased trigylceride mobiliazition by activating the hormone sensitive lipase
what is the effect of epinephrine and glucagon on FA OXIDATION
it increases fatty acid tissues execpt the CNS and RBC
where is fatty acids built
cytosol
what is it called when you build a fatty acid
fatty acid synthesis
fatty acid biosynthesis
what is the trigger to start the build up of fatty acids (precursor)
acetyl coa
why is acetyl coa (where is it seen)
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
can acetyl coa form fatty acids start in the mtiochondira
no , it needs to esceape the mtio and make the fatty acids i nthe cytsol of the cell
true or false: acetyl coa has a slight deviateion from tthe kreb cycle in order to form fatty acids
true
what is the first step acetyl coa must do in order to form a fatty acid
mustt merge with oxaloacetate to form citrate
will acetyl coa form citrate and aALWAYS leave the kreb cycle to form fatty acids
no
onyl when there is a need to form fatty acids
does actyle coa mix with oaxlo and form citrate in the mito or the cytsol
in the matrix
how deos citrate exit the mitochondira
needs a shuttle CITRATE SHUTTLE
TRue otr false; citrate can. exit the mitochondira easily (diffusion)
false it needs the citrate shuttle
what is the function of of the citrate shuttle
allows citrate to move past the mitochondria and into the cytosol
true or false: once citrate enters the cytsol, there is a reverese reaciton to turn it back into acetyl coa
true
why do we do the reverse reaction
there is no transporter to allow acetyl coa to go out of the memrbane
true or falseL acetyl coa is is hydrophillic and can easily pass through membvraen
false it is hydrophobic and needs a carrier to getit through the membrane
once citrate enters the cytsol, what reaction happens
citrate gets split back into acetyl coa and oxaloacetate (needs atp to get this reaction started)
does acetyl coa start as acetyl coa to form tvhe long chain fatty acyl coa
false it needs to get transformed into maloyn coa
what is the intiial fat compound made from actyl coa
malonyl coa (carbons in it that will add onto the malnyl group to because a long carbon fat chain)
WHat is the final profuct of fatty acid syhtesis
fatty acyl coa
can fatty acyl coa be immediately borken down
fatty acyl coa
what is the primer of fatty acid synthesis
acetyl coa
what is the purpose of malonyn
allows the addition of two carbons units
the two carbons that are added to the acetyl coa from malonyl must be reduced by what
for every 2 carbon unit, it must be reduced by 2 NADPH
what is the reaction for the syntehsis of palmiteic acid (c16)
Acetyl coa (2C) + 7 Malyn COa +14 NADPH + 14 H gives yyou
Palmmited acid (16 C) + 7 CO2 + 14 NADP + 8Coa + 6 h20
how does fatty acid synthesis work (general)
the maloyn coa (the backbone) will keep added carbons to the chain to form the proper length that it is programed to do
how many nadh is needed for every 2 carbons
2 nadph
becsides acetyl coa, what is needed in adequate concentrations for fatty acid syhtesis
carbohydate availability
why is it important to have adewuate carb availability
glucose goes to pyruvate which will ctreate the acertyl coa needed for fatty acid synthesis
what are the 3 important cycles coonnected to fatty acid sythesis
- glycolysis (need to make pyruvate)
- pyruvate oxidation to make acetyl coa
- kreb cycle to form the citrate
- pentose phosphate pathway to form the NADPH
where does the NADPH for fatty citrate come from
PPP
where does glucose/pyruvate for the fatty acid synthesis come from
glycolysis
where does the acetyl coa/citrate come from for the fatty synthesis
kreb cycle
why is glyvolysis important for fatty acid synthesis
need adequate presentation of the acetyl coa unitts to the cycle which are coming from glycoslysi (pyruvate oxidation)
what stimulates fatty acid synthesis
INSULINE
what enzyme allows malyn coa to form the fatty cid
fatty acid synthase
in order to fatty acids to be oxidzed where do they need to travel to
the mitochondira
true or false: fatty acids can easliy flow through the mitochondiron membrane
false they are hydrophbic therefore need a carrier
how much energy is needed to push the fatty actl group through the membrane
2 atp (ATP goes toAMP)
what is the reason that the long chain fatty acyl must go out of the cytosol and into mitp
must find its way back to the mitcohondira so it can be brolen down and deliver its products to the ETC and kreb cycle
what must bind to the fatty acyl group to start fatty acid transport into the mitochondira
carnatine
what does carnatine replace
replaced the Co a group in the fatty acyl
true or false: carnatine is a protein found within the blood
false, it is found within the cytsol of a cell
how does the carnatine attach to the fatty acyl group
it requires atp > amp to charge the reaction
whwere is carnatine acetyltransferase 1 found
outer mitchondiral membrane
whatt is the function of the carnatine actyl transferase 1 enzyme
binds the carnatine fatty acyl and pushes it into the intermembrane space
what does the carnatine fatty acyl need to enter tthrough the inner mitochondiral memrbane
needs to have a tranport protein
once the carnatine fatty acyl has travelled through the inner mithoncdira membrane, what enxyme is it faced iwht
carnitne actyltransferase 2
what is the function of the carnatine acetyl transferate 2 in the matrix
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
whatt does the processs of fatty acid transportation do
transportes fatty acid from the cytsoll to the mitchondira
what is needed to get the uptake of fatty acid into the cell
carnatine and the carnatine acetyltransferaase enxymes
true or false: once carnatine is disloasged from the fatty acid it is degreaded
false, it will go back out to the cytsolto be bound again
hwo can carnatine easily travek throu gh the mitchondira membrane
it has polar heads
what happens to the carnatine actyl transferase 1 once it binds with carnatine
changes conformation and allows the long chain fatty acid to enter the intermembrane space to travel throug hthe transporter
once the fatty acyl travels througj the inner memrbane of the mitchondira,does it still have its carnatine group attached
yes
how is carnatine removef from the fatty actid
carnatine acetyl transferase 2
what replaced the carnatine that is dislodged from the fatty acid and what is that fucntion
a coa group to regorm the fatyl acid group inside the memrbane
explain the process of biosyhtesis of fats
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
what tis the enzyme that converts acetyl coa to malonyl coa
acetyl coa carbxoylase
what is the enzyme that converts maloyn coa to the faty ACID (what allows you to add carbons )
fatty acid synthase
what is the process of fatty acid transport from the cytsol to the mitochondira
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
where does fatty oxidattion (beta oxidation) occur
in the mitochondira
why is beta oxidation in the mitchodnira
so the products made (NADH and FADH and Acetyl coa) can go and enter the kreb cycle and the ETC
what is the prupose of beta oxidation
BREAKING down fatty acids from for energy
what is the main sequential event for beta oxidation
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
everytime you go through one cycle of beta oxidation, what do you form
1 NADH
1 FADH2
1 Acetyl coa
where does the FADH2 and NADH from the beta oxidation go
to the ETC for ATP
where does the acetyl coa formed form beta go
Kreb cycle to form more NADH AND FADH2 and then the ETC
how many steps of beta oxidation are there
4 steps
what is the formula for number of cycles of beta oxidation
(number of carbons/2) - 1
give an example of calcualtion the number of cycles of palmitic acid
palmitic = 16 c
16 C/ 2= 8
8-1
=7
how many carbons do you break off for ebvery cycle of beta
2 carbon (as acetyl coa)
what is the 14 carbon called from palmatate
myriostol coa
once you are left with a 2 carbon entity will it reenter into beta oxidation
no , it will be acetyl coa and will just enter the kreb cycel
what are the 2 cofactors needed for beta oxidation
NAD gets reduced to NADh
FAD gets reduced to FADH2
how many atp is made from 1 acetyl coa of beta
12 atp (because kreb makes 3 nadh = 3 atp, 2 fadh2= 2 atp and 1 atp from gtp)
for each nadh procudes in beta, how many atp can be formed from ETC
3 atp
for every FADH2 produced in beta, how many atp
2
what are the 4 main reactions for beta
dehydration
hydration
dehydrogenation
thiolysis
true or false: the chain will continue to break down (ie. beta will continue) until you are left with 0 carbons
false it will stop when you have 2 carbons left becausre that will be actyl coa
true or false: the acetyl coa from beta is wasted
false it goes to kreb cycle for atp
true or false: the acetyl coa from beta is wasted
false it goes to kreb cycle for atp
why is there a net atp in beta of 129 and not 131
you lose two phosphates/2 atp to get the fatty acid into the mitochondira (ATP goes to AMP)`
how many atp can be formed for a 16 carbon fatty acid
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
what is important to note in terms of oxygen for the brta oxidation
you need greater levels of xoygen to bind all the elctrons that are coming off of the FADH2 and NADH prduced from the beta
the acetyl coa formed from the beta oxidation can only go to the kreb cycle?
no it can go to the kreb cycle but it can also develop ketone bodies
how are ketone bodies rpoduced
by 2 acetyl coas
