Electron transport chain

In previous blog we have studied about 2nd step of aerobic respiration Kreb's cycle in which pyruvate molecule first changed into acetyl group and then acetyl group molecule carrry out kreb's cycle and ATP were produced and some coenzymes like NAD,FAD were reduced into NADH AND FADH.

Now in this blog we will study about 3rd step of aerobic respiration called as Electron transport chain.

WHAT IS ELECTRON TRANSPORT CHAIN:

The last step of aerobic respiration in which reduced co enzymes of kreb's cycle are oxidized and energy is produced and their electrons are pass through along a series of oxidation reduction reaction to the final acceptor(oxygen).

Electron transport chain occurs in mitochondria of cell.

COMPONENTS OF ELECTRON TRANSPORT CHAIN:

1-NADH(Q) REDUCTASE OR NADH -DEHYDROGENASE COMPLEX(1),further composed of FMN and FE-S COMPLEX.

2-FADH-DEHYDROGENASE COMPLEX(2)

3-Coenzyme Q or UBIQUINONE (MOBILE CARRIER)

4-CYTOCHROME REDUCTASE COMPLEX(3) further composed of cyto-b,Fe-s,cyto-c 1.

5-Cytochrome -c (mobile carrier)

6-Cytochrome oxidase complex(4) further composed of Cyto-a,Cyto-a3 and copper.

PASSAGE OF ELECTRON FLOW:

The electron transport chain is actually the oxidation of coenzymes they were reduced in kreb's cycle.

When NADH and FADH were oxidized there highly energy electrons are pass through different electron carrier from top to bottonm it is like downhill energy.

First electrons are captured by cytochrome b and then transfer to cytochrome c and then to cytochrome-a,cytochrome a-3 and in last these elctrons are accept by oxygen molecule and react with hydrogen molecules to form water molecule.

When electron transfer from one carrier to another carrier it losses some energy which help in formation of ATP from ADP and inorganic phosphate.

Keep in mind.in electron transport chain each next molecule or electron carrier is at less energy level than previous one.

MAIN POINT:

Here cyt-f is not present unlike present in light photosynthetic reaction.

IMPORTANT MCQS IN THIS TOPIC:

1-1st process in electron transport chain will be:

Answer: OXIDATION OF CO ENZYMES (through NADH and FADH dehydrogenase)

2-The final acceptor of electron is:

Answer: OXYGEN MOLECULE

3-Electron transport chain occurs in:

Answer: MITOCHONDRIA

4-How many net oxidative ATP formed from one glucose molecule: