Similarities and Differences between Cell Respiration and Photosynthesis
Similarities:
1. ATP is a key molecule in each
2. G-3-P is formed in both processes- In Glycolysis (cell respiration)
and in Calvin cycle (photosynthesis)
3. Both have 2 processes feeding into one main one: Cell Respiration
utilizes Glycolysis and Citric Acid Cycle to funnel energized
electrons to Oxidative Phosphorylation process, PSII and PSI
provide ATP and reducing power to Calvin Cycle
4. Both utilize cycles where starting material is regenerated after
molecules leave the cycles (Citric acid cycle- Cell Respiration,
Calvin cycle- Photosynthesis)
5. Both rely on movement of electrons for operation
6. Both use electron transport chains in production of ATP
7. Both use chemiosmosis to generate ATP
8. Mitochondria of cell respiration and chloroplasts of photosynthesis
have distinct similarities, for example
 as above, proton pumps pump H+ across a membrane from low to
high concentration. An endergonic process requiring energy
 protons diffuse back across membrane through ATP synthase,
driving synthesis of ATP
9. Can observe emergent properties via multiple steps in both
processes
Differences:
1. Goals: ATP synthesis is main reason for cell respiration, whereas ATP
is only a required product for photosynthesis to be able to create
glucose.
2. Reactants: glucose and oxygen, Cell respiration, carbon dioxide and
water, photosynthesis
3. Products: carbon dioxide and water, Cell respiration and glucose and
oxygen, photosynthesis
4. Oxygen is exhaust of photosynthesis whereas carbon dioxide is
exhaust of cell respiration
5. Source of elections: in photosynthesis, electrons come from water and
end-up in glucose. In cell respiration, electrons extracted from glucose
and end up in water
6.
Electron Carriers: NADH and FADH2 carry electrons in cell
respiration, NADPH carries electrons in photosynthesis
7. Location: chloroplasts for photosynthesis and mitochondria for cell
respiration
8. Proton movement:
 Protons are pumped into the inner membrane space of the
mitochondria (cell respiration), protons are pumped into the thylakoid
space of the chloroplasts (photosynthesis)
 Protons diffuse back into the matrix of the mitochondria (cell
respiration), protons diffuse into the stroma of the chloroplast
(photosynthesis)