ATP synthesis Flashcards
(9 cards)
what are catabolic & anabolic reactions?
examples
catabolic:
- breaking down large molecules into smaller ones
- potential energy is being released –> exergonic
e.g. cellular respiration
anabolic:
- synthesis of large molecules from smaller ones
- energy is required –> endergonic
e.g. photosynthesis
what happens to the energy released during catabolic/ exergonic reactions?
example?
- used to do work
- produce heat
- involved in redox reactions, driving the electron transport chain
what are 2 major exergonic/ catabolic processes, that contribute to ATP synthesis?
- fermentation: sugars degraded without oxygen into CO2 + ethanol or lactic acid
- respiration: the degradation of glucose, the process is “pulled” by oxygen
Where does cellular respiration take place?
- cytoplasm (cytosol): glycolysis
- mitochondria
–> matrix: krebs cycle
–> intermembrane space: oxidative phosphorylation
what are the 4 steps of cellular respiration?
What are the reactants and products at these steps?
-
glycolysis:
- 1x 6C glucose –> 2x 3C pyruvate
- 4 ATP made - 2 ATP used –> 2 ATP
- 2 NAD+ + 4e- + 4H+ –> 2 NADH + 2H+ -
pyruvate oxidation
- 2x 3C pyruvate –> 2 CO2 released + Acetyl-CoA (2C + coenzyme A)
- 2 NAD+ –> 2 NADH -
krebs / citric acid cycle:
- 4 CO2 produced
- 2 ATP
- 6 NADH
- 2 FADH2 -
oxidative phosphorylation:
- NADH –> NAD+
- FADH2 –> FAD
- ETC (gets electrons from nadh and fadh2)
- 1/2 O2 + electron –> H2O
- chemiosmosis (H+ gradient) –> ATP synthase
- ADP + Pi –> ATP
What is the benefit to cellular respiration taking place through so many steps?
the slower, gradual release of energy (released through oxidation of glucose) is more useful than a single, large release of energy all at once, which cannot be harnessed efficiently for work
What are the oxidising agents in cellular respiration?
NAD+ and FAD:
- accepts electrons
- act as a coenzyme/ can easily flow between oxidised and reduced state: NAD+ <–> NADH
- provides ETC with electrons
