Respiration Flashcards
Name the structures in the mitochondria and their basic function
Outer membrane - compartmentalisation
Inner membrane - contains proteins like electron carriers for respiration, and fold into cristae
Cristae - Increases surface area on inner membrane for oxidative phosphorylation
Intermembrane space - ETC pumps H+ ions into this space for ATP synthesis
Matrix - Contains enzymes for link and Krebs and contains mitochondrial DNA
Explain glycolysis
- First stage of aerobic respiration, in cytoplasm, anaerobic
- Glucose converted to hexose bisphosphate by 2 ATP molecules being converted into 2 ADP
- This splits into two triose phosphates
- Phopshate group from the cytoplasm is joined to each to form 2 hexose bisphosphates
- Two pyruvates are formed (3 carbons), the two phosphate groups are collected by ADP to make ATP
- NAD takes a hydrogen atom from triose bisphosphate an becomes reduced
What are the products of glycolysis?
2x pyruvate
2x ATP (net)
2x Reduced NAD
What is substrate level phosphorlyation?
ATP production from ADP without electron transport chains or ATP synthase.
Simply, what happens in the link reaction and where is it?
- Pyruvate is converted into acetyl coA (2 carbon)
- Mitochondrial matrix
Explain the link reaction
- Carbon dioxide is released from pyruvate so a carbon is lost
- NAD becomes reduced, so having lost a hydrogen, pyruvate becomes reduced
- An acetyl group formed from pyruvate joins with coA to form acetlycoA for stability
What type of reaction is the link reaction?
Oxidative decarboxylation
Explain the Krebs Cycle
- CoA (2 carbon) joins with oxaloacetate (4 carbon) to make a 6 carbon molecule which is citrate
- CO2 is released and NAD becomes reduced to make a 5C molcule
- Same process to make a 4C molecule
- ADP becomes phosphorlyated and forms ATP via substrate level phosphorlyation
- FAD is then reduced to a=make 2 ATP
- Another NAD is also reduced
What are the products from the link reaction and krebs cycle?
- 4 reduced NAD
- 1 reduced FAD
- 3 CO2 molecules (waste product)
- 1 ATP
What are the 3 places the final stage of aerobic respiration take place, and what is this process called?
- Matrix, cristae, intermembrane space
- Oxidative phosphorlyation
How many protons do reduced FAD and NAD have and where do the protons come from?
Reduced NAD - 1 proton
Reduced FAD - 2 protons
Protons from the hydrogen ions, which has one proton
Outline the steps of oxidative phosphorylation
- Reduced NAD/FAD reduce protons and electrons
- Electrons enter the electron transport chain
- Electrons release their energy as they travel along the ETC, this energy pumps protons (H+)across the cristae into the intermembrane space by active transport
- This increases the proton conc in the IM space
- Because of this conc gradient, protons move across the ATP synthase by osmosis, which is chemiosmosis, driving ATP production
- Oxygen acts as the terminal electron acceptor, reacts with protons and makes water
Define chemiosmosis
Diffusion of protons down the electrochemical/proton conc gradient through ATP synthase
How is ATP formed in chemiosmosis?
Protons provide the proton motive force to turn the enzyme to bring ADP and Pi (phosphate group) closer together, making ATP
Why does water need to be made at the end of oxidative phosophorylation?
Hydrogen ions in the mitochondria will cause the pH to reduce and therefore the conditions to become acidic
This would mean all the proteins would denature like the electron carrier and ATP synthase
