Question

Describe the similarities and/or differences between the following (at least 4 similarities or differences for each):

1. production of ATP in oxidative phosphorylation and production of ATP in the membrane associated (light) reactions
2. photosystem I and photosystem II
3. citric acid cycle (Kreb cycle) and Calvin cycle

Answer 1

1.

	ATP production in oxidative phosphorylation	ATP production in the membrane-associated (light) reactions
Similarities	ATP is produced as in both the reaction types.
	A membrane-associated electron transport chain is utilized to transfer electrons from one to the other.
	A proton gradient is created in both types.
	The proton gradient is used to produce ATP through ATP synthase.
Differences	NADH and FADH2 act as an electron source.	H2O acts as an electron source.
	H2O forms in the reaction.	H2O is split in the reaction.
	It occurs in mitochondria.	It occurs in chloroplast.
	The energy comes from electrons produced due to oxidation of biomolecules is used as source of energy.	Light energy from the sun is used as source of energy.

2.

	Photosystem I	Photosystem II
Similarities	Both the systems are found in the membrane of the thylakoid.
	Chlorophyll is present in both the systems which convert light energy to chemical energy.
	In both, photon causes excitation of electrons.
	Carotenoid is present in both the systems.
Differences	P700 is the photo center.	P680 is the photo center.
	It is present on the outer surface of thylakoid membrane.	It is present on the inner surface of the thylakoid membrane.
	The photopigments absorb light of 700nm wavelength.	The photopigments absorb light of 680nm wavelength.
	It is involved in both cyclic and non-cyclic photophosphorylation.	It is involved only in non-cyclic photophosphorylation.

3.

	Citric acid cycle	Calvin cycle
Similarities	ATP acts as a key molecule in both the processes.
	These occur in eukaryotic cellular organelles (mitochondria and chloroplast).
	These are cyclic pathways of cellular metabolism.
Differences	It occurs in the mitochondrial matrix.	It occurs in the stroma of chloroplasts.
	ATP and CO2 are produced in this process.	ATP and CO2 are used in this process.
	It is a catabolic process.	It is an anabolic process.
	It occurs in all aerobic organisms.	It occurs only in plants.