Unit 4: Celluar Respiration Flashcards
Pyruvate Oxidation, Krebs Cycle, ETS and Chemiosmosis
What are the 3 steps of pyruvate oxidation?
- Decarboxylation
- oxidation
- conjugation to CoA (coenzyme A)
Where does pyruvate oxidation occur?
In the mitochondria
Where does the Krebs cycle occur?
In the mitochondrial matrix
What are the products of pyruvate oxidation?
acetyl CoA, CO2 and NADH
What are the products of the citric acid cycle and where do they go afterwards?
- NADH and FADH2 are used in ETS
- GTP is also produced, which can be turned into ATP
- CO2
What is the electron transport system?
- electron transport complex
- a series of redox reactions
- eventually transfer electrons to O2
What happens when electrons are transferred?
Energy is released. The energy is used by protons to transport H+ from matrix to intermembrane space.
What does ETS create?
A proton gradient
What are the characteristics of complex 1?
- Inside mt inner membrane
- uses NADH dehydrogenase
- transfers electrons from NADH to Q
- proton pump
What are the characteristics of Q?
- ubiquinone
- lipid
- free within mt membrane
- transfers e from I to III OR II to III
- carries 2 e
- reduced form is QH2
What are the characteristics of complex II?
- within inner mt membrane
- uses succinate dehydrogenase
- transfers electrons from FADH2 to Q
- IS NOT A PROTON PUMP
What are the characteristics of complex III?
- within inner mt membrane
- uses cytochrome reductase
- transfers e from Q to cytochrome c
- proton pump
What are the characteristics of cytochrome c?
- within mt inner membrane
- faces intermembrane space
- transfers e from III to IV
What are the characteristics of complex IV?
- within inner mt membrane
- uses cytochrome oxidase
- transfers e from cytochrome c to O2
- proton pump
What happens if there is no oxygen present once the e gets to complex 4?
The electrons don’t move and then nothing works.
What are the 2 ETS reactions?
1) I –> Q –> III –> cyt. c –> IV
2) II –> Q –> III –> cyt. c –> IV
How are molecules across mt membrane?
a) through outer membrane into intermembrane space
b) through inner mt membrane–into matrix
What does the movement of molecules across the outer membrane entail?
- the use of porins–channel-forming proteins
- allow most small molecules to cross outer membrane
What does the movement of molecules through the inner mt membrane?
- diffusion of O2 (enters) and Co2 (exits)
- translocases
- NADH transfers H to shuttle
What is the purpose of chemiosmosis?
ATP production using ATP synthase
What are the structures used in chemiosmosis?
- F0= cylinder within inner mt membrane
- F1= water soluble catalytic complex (matrix side inner mt membrane)
- y (gamma) subunit acts as a rod that turns
- there are 4 other subunits
How does ATP synthesis work in chemiosmosis?
- Binding-change mechanism protons flow down electrochemical gradient through F0
- Causes y to rotate
- causes conformation changes
- allows Pi to add on to ADP
- ATP is synthesized
What is the process of creating ATP called?
Oxidative phosphorylation
How many ATP molecule are formed for every NADH from the CAC? FADH2?
3 ATP per NADH
2 ATP per FADH2
