Question

A living cell extracts energy from organic "fuel" molecules in small, enzyme-catalyzed steps. This allows the process of energy extraction to be regulated. but less free energy is released from the molecules than would be released by burning them O and all of the energy is released as heat that can be used to do work in the cell O and some of the energy is stored in bonds of activated carriers O and more free energy is released from the molecules than would be released by burning them

Answer 1

28) every chemical reaction specially use of energy from fuel in short steps make more free energy to be released than would be. Released from burning thats why the electron transport chain of MITOCHONDRIA is divided into various step not directly from complex 1 to IV because if this happens then combustion will be resulted and heat will be generated but free energy will be very less।

)if the concentration is same in both side then also ions can cross because voltage gradient can be present which may be result3d by other ions.

Similarly zero voltage gradient will not be effective if concentration of potassium in both side is different.

So is only possible to get equilibrium when both side movement rate will be same.

30) photosystem II accepts electrons from water.

NADP+ is the final ELECTRON acceptor.

Cytochrome b6f complex pumps protons into thylakoid lumen .

Photosystem I get 3lecyrons from another photosystem.

31)most of the receptor come back to their original position by recycling because these protein is very much needed for mediating signalling cascade. And to synthesis this protein huge amount of energy is needed that's why they are not usually digested.

Thank you