Lecture #28 - B oxidation Flashcards
Where does B oxidation occur but where does the activation of FA occur?
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FA as fuel:
- They are the most ____ fuel - glycolysis is good but these are great
- Fat is the ____ _____ reserve (what precent of mammalian body weight?) - what can you say about how excess fat or sugar is stored
- Compare fats to carbs by mass and then by redox and then by water
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Delivery of FA for fuel:
- What breaks TAGs down in the adipose tissue so they can passively travel into blood?
- In the blood, what do the FFA need to be bound to and why? (and how)
- Where are the two components transported to respectively?
- Regarding the transport of FFA across cell membrane - it’s passive because down conc grad but can you sometimes have transporters - why?
- In the tissues, what binds to FFA? Why?
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Fatty acid activation: put molecule into a form so we can get energy out
- when/where does it occur?
- FA are activated for oxidation by what?
- explain the process plz
Okay so you have the CoA-SH and you get energy from hydrolysis of ATP and using acyl-coA synthetase, you made fatty acyl-coA (a carbon chain of any length).
In doing so, you formed AMP (not ADP) i.e. essentially used 2 ATP - equivalent to 2 ATP - because it’ll take 2 ATP to regenerate this.
Take this into account when doing calculations
Where does the actual oxidation of FA occur? (the FA are activated for oxidation in cytosol)
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Transport of FA into mitochondria
How
So the fatty acyl-CoA travels through the fatty acyl-coA transporter in the outermembrane of the mitochondria
Then, it gets converted into fatty acyl-carnitine (since inner membrane doesn’t have transporter for fatty acyl-coA). In the process, carnitine gets converted into coA-S. After fatty acyl-carnitine is across the inner membrane via a carrier, another thing (carnitine acyltransferase II) does the opposite and then gets fatty acyl-coA back (becausee that’s the form we can use).
Carnitine suppliments:
Explain
If you eat this, they say it’s good for weight loss/stops fat accumulating because you’re able to get more to the oxidation stage - won’t store. Buuuuut, our body makes it so our body will regulate the amount of stuff idk. Carnitine supplements just go out because just bc you have more of it doesn’t mean you’ll get FA activation etc
B oxidation general:
- What are the two requirements for FA to be used in beta oxidation?
- Is any ATP made in B oxidation?
- The energy that is released - where does it go?
- What is the product of it and where does it go?
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Beta oxidation:
- What part of the FA will change in the process? Give an overview of the B Oxi plz
- How many steps are there what are they all and what do they involve?
- Go read the yellow highlighted overview
- For each round of B oxidation, what do you make?
- What is the formula for number of rounds and number of C?
- If you have 7 rounds of B Oxi, how many NADH, FADH2 and acetyl CoA are formed? Why?
What’s the overall equation?
3 - Oxidation and involves the beta carbon losing 2H and double bonding the O. NAD+ provides the oxidising power for this and gets reduced (H+ left) so essentially, you’d formed two reduced coenzymes in one cycle and captured the energy in them
- The Bond between the beta carbon (attached to the CH2-R and the alpha carbon attached to C=O-S-CoA). Okay so you basically chop the bond between CB and Ca and keep cleaving so like at the end of cycle you’ll end up with the molecule being 2C shorter. Hard to cleave the bond when in that single bond arrangement so first three steps are to rearrange so it can be cleaved
- # 1 - Oxidation and involves FAD being reduced and the double bond forming. FAD used because it’s hard to oxidise the Fatty Acyl-CoA to TRANS-Enoyl-CoA and NAD+ doesn’t provide enough oxidative power for it
- Acyl-CoA dehydrogenase does this bc redox
#2 - Hydration and involves a H2O being added and the OH is added to beta carbon -involves a hydrase enzyme
