Class notes
Lecture Notes
- Course
- Institution
Lecture notes of 8 pages for the course Membrane and cellular Biochemistry at QMUL
[Show more]
1 review
By: betulalm • 3 year ago
Seller
Follow
fatima-attia
Reviews received
Content preview
ATP SYNTHASELearning objectives:
1. Describe the overall structure and subunits composition of ATP synthase
2. Explain the functional roles of the F 1 and F0 domains of ATP synthase
3. Outline and explain the experiments that showed these functions
4. Explain the binding change mechanism of ATP SYNTHESIS
5. Discuss how the structure of the F1 head can be used to explain the mechanism of ATP synthesis by ‘’rotational catalysis’’
6. Explain how rotation of the central stalk was shown experimentally
7. Explain the mechanism of coupling between proton translocation through F 0 and ATP synthesis by F1
What we know about ATPase comes from prokaryote cells and not eukaryote cell.
Believed ATPase to be present before membrane but for this course believe that membranes came about first
The Krebs cycle
all the reactions in the Krebs cycle is an enzyme catalysed reaction
Citric acid is found in lemonade and orange juice
Kerb cycle and urea cycle are connected by the aspartate shunt
There are a few wheels (molecular machines that go around) in nature.
- i.e. ATP synthase & bacterial flagella
The machinery for ATP formation: F1
Nearly all enzymes catalyse equilibrium reactions (reactants to products).
Isolated spherical particles (coupling factor 1, F1) catalyse ATP hydrolysis: F1 is an ATPase
Hydrolysis of ATP by F1 is a reversible reaction:
Reversibility of ATPases: even the Na+/K+ ATPase can catalyse ATP synthesis
, How does the Na+/K+ ATPase pump work
- Na+/K+ pump is an ATPase, which uses chemical energy to energise the plasma membrane
- Sodium ions bind to Na+/K+ ATPase pump from the cytosol and potassium ions are released into cytosol
- ATP hydrolysis results in change in conformation
- Sodium ion released into the ECF and potassium ions bind again
How to drive ATP synthesis
- If potassium inside and sodium outside the cell are very high (non-physiological)
- Then ion gradient can drive ATP synthesis by the Na +/K+ ATPase pump.
Even the Na+/K+ ATPase physiologically and biologically only hydrolysis ATP but if push the equilibrium far enough, Na +/k+
ATPase will synthesis ATP
Usually enzymes can catalyse ATP hydrolysis and synthesis depending on where the equilibria is
Na+/K+ ATPase can convert proton motive force into ATP or hydrolyse ATP to generate a proton gradient
Experiments with sub mitochondrial particles demonstrated that F1 is required for ATP formation and F0 is a proton
channel
Experiment connected both ATPase to proton motive force and ATP synthesis
Mitochondria broken up into little particles
- If disrupt cellular membranes it will form vesicles inside out
- If provide the vesicles with NADH and cytochrome c will run the respiratory ETC and can measure a proton
motive force is generated (pumping proton into vesicles). Can add ADP to measure synthesis of ATP
- If treat the vesicles with urea, the F1 groups will be knocked off the ATPase and can no longer synthesis ATPase
and don’t generate a proton gradient if have NADH or cytochrome c
- The ATPase is not involved in proton gradient generation
The structure of the ATP synthase
Spherical F1 head
- F1 contain five subunits with a composition of α 3β3δ γε
There are 3 betas and 3 alphas arranged sequentially (1 alpha 1 beta)
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller fatima-attia. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.12. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
76462 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now