Metabolism Flashcards
(19 cards)
How are the electron transport and ATP synthesis coupled?
Electron carriers
What are the properties of electron carriers?
Electron carriers
How do they enable the formation of transmembrane proton gradient?
What is the difference in locations of the proton gradient in prokaryotes vs eukaryotes?
What are energy conservation options for chemoorganotrophs?
- substrate-level phosphorylation
- oxidative phosphorylation
What is the difference between substrate level phosphorylation and aerobi/anaerobic respiratory mechanisms for generating ATP?
- substrate-level phosphorylation: fermentative mechanism in which ATP is synthesized at discrete reaction steps
- oxidative phosphorylation: respiratory mechanism in which ATP is syntehsized by harnessing the proton motive force
photo-phosphorylation is used in phototrophs and has a similar mechanism to oxidative phosphorylation
What are characteristics of substrate-level phosphorylation?
- direct ATP formation
- phosphate groups are directly transferred from another molecule to ADP
- doesn’t need oxygen or ETC
- happens in cytoplasm and mitochondria
What are characteristics of oxidative phosphorylation?
- more ATP produced (slower)
- needs oxygen
- uses an electron transport chain and ATP synthase
- occurs in mitochondria (inner membrane)
cellular respiration
Which form of ATP synthesis requires cytoplasmic membrane participation? why?
Respiration or oxidative phosphorylation in prokaryotes because they don’t have a mitochondria so it will happen across the cytoplasmic membrane rather then the inner membrane of the mitochondria (eukaryotes).
What is the difference between inhibitors and uncouplers of ATP synthesis?
What reactions in glycolysis involve oxidations and reductions?
What is the role of NAD+/NADH in glycolysis?
Why does fermentation only release a small amount of energy from the primary electron donor?
- the carbon is not completely oxidixed
- the difference in E0’ between reduced substrate and fermentation product is small
Name 5 electron transport carriers. Which are proteins and non-protein?
What does NADH dehydrogenases do?
- membrane bound (inside cytoplasm)
- binds NADH
- transfers 2e- + 2H+ to flavoproteins
What do flavoproteins do?
- proteins bound to a riboflavin derative
- accepts 2e- + 2H+ from NADH dehydrogenase
- donates 2e- to next carrier
electron transport carrier
What do iron-sulfur proteins do?
- non-heme iron proteins
- contain fe-S clusters coordinated by cysteines in protein
- carry electrons only
- reduction potentials vary from protein to protein
electron transport carriers
What do cytochromes do?
- heme prosthetic groups
- iron center
- single electron transfer
- several classes with varying reduction potential
- either receiving or giving (not both
- doesn’t deal with protons
What do Quinones do?
- hydrophobic found in membrane
- accepts 2e- + 2H+ from previous carrier
- donates only 2e- to next carrier
