Question

Compare and contrast Oxidative Phosphorylation and Photophosphorylation. Write out at least 5 similaritites, differences, or some combinaion of the 2.

Answer 1

Oxidative phosphorylation is the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH₂ to O₂ by a series of electron carriers. This process, which takes place in mitochondria, is the major source of ATP in aerobic organisms.

OR

Oxidative phosphorylation is defined as the synthesis of ATP by phosphorylation of ADP for which energy is obtained by electron transport and which takes place in the mitochondria during aerobic respiration.

During oxidative phosphorylation, electrons are transferred from electron donors to electron acceptors in redox reaction. During this energy is released,energy released is then capturedas a proton gradient, which is used to form ATP. And this process is known as chemiosmosis. the electron transfer chain and chemiosmosis together make oxidative phosphorylation.Oxidative phosphorylation is a vital part of metabolism.

It works as

1.NADH and FADH give their electons to molecules near them and transfer of electron begins.

2.As electron are passed they move from high energy level to low energy level releasing energy. some of the energy is used for proton pumping and a electromchemical gradiennt is generated.

3.at the end of transport chain electron are transferred to molecular oxygen. now as the proton moves back into the matrix it passes through ATPsynthase enzyme and generate ATP

Photophosphorylation

In the process of photosynthesis, the phosphorylation of ADP to form ATP using the energy of sunlight is called photophosphorylation.

In photophosphorylation, light energy is used to create a high-energy electron donor and a lower-energy electron acceptor. Electrons then move spontaneously from donor to acceptor through an electron transport chain.

photophosphorylation is further classified in two types

1.cyclic

This form of photophosphorylation occurs on the stroma lamella or frets. In cyclic photophosphorylation, the high energy electron released from P700 to ps1 flow down in a cyclic pathway.

2. Non cyclic

non-cyclic photophosphorylation, is a two-stage process involving two different chlorophyll photosystems. Being a light reaction, non-cyclic photophosphorylation occurs in the thylakoid membrane.

THERE ARE THREE MAJOR SIMILARITIES BTW PHOTO PHOSPHORYLATION AND OXIDATIVE PHOSPHORYLATION AND THEY ARE

1. Both processes involve generating a proton electrochemical gradient across a membrane, by pumping protons from an area of lower concentration to a higher concentration.

2. Proton gradient is generated.

3. Energy of the proton gradient is used by making ATP with the help of an ATP synthase.

DIFFERENCES