1. If the inner mitochondrial membrane were rendered as permeable as the outer membrane, how would that affect oxidative phosphorylation? Which specific processes would stop and which remain? 2. Present two types of benefits derived from separating the reactions of glycolysis in the cytosol from those that occur during the citric acid cycle in the mitochondrion. Solution Outer membrane of mitcochondria is a phospholipid bilayer. Outer membrane is permeable to ions and molecules as it possess the proteins, porins in its structure of outer membrane. Inner mitochondrial membrane is complex and permeable to water and gases only. Electron transport chain and chmiosmosis occurs in inner mitochondrial membrane. Oxidative phosphorylation involves in the production of a proton gradient through the passage of electrons from one molecule to another. This proton gradient has been used in the production of ATP. If the inner mitochondrial membrane like that of outer mitochondrial membrane also becomes porous to ions, the oxygen cannot be able to accept electrons and cannot able to pick the protons to produce the water at the end of electron transport chain. This results in a break in chemiosmosis and a break in the production of ATP. NADH and FADH2 gets produced on inner mitochondrial membrane due to its change in structure like that of outer mitochondrial membrane. But the NADH and FADH2 cannot donate electrons and again both these cannot turn back into NAD and FAD. Thus regeneration of electron carriers gets stopped. The pumping of H+ into intermembrane space from matrix due to transfer of electrons from jhigher energy levels tolower energy level produces the electrochemical gradient. Due to imprpper electron gradient, H+ pumping gets stopped from the matrix to the intermembrane space. Generally H+ is higher in intermembrane space and lower in matrix when the energy has been produced, but due to a change in structure of inner mitochondrial membrane, the H+ is higher in matrix and lower in intermembrane space. This leads to lack of production of ATP due to unavailability of proton gradient in the intermembrane space. Due to unavailability of reduced redox potentials NAD and FAD, the processes of glycolysis and citric acid cycle gets impaired. Outer membrane of mitochondria is a phospholipid bilayer. Outer membrane is permeable to ions and molecules as it possess the proteins, porins in its structure of outer membrane. Inner mitochondrial membrane is complex and permeable to water and gases only. Electron transport chain and chemiosmosis occurs in inner mitochondrial membrane. Oxidative phosphorylation involves in the production of a proton gradient through the passage of electrons from one molecule to another. This proton gradient has been used in the production of ATP. If the inner mitochondrial membrane like that of outer mitochondrial membrane also becomes porous to ions, the oxygen cannot be able to accept electrons and cannot able to pick the protons.

1. 1. If the inner mitochondrial membrane were rendered as permeable as the outer membrane, how
would that affect oxidative phosphorylation? Which specific processes would stop and which
remain?
2. Present two types of benefits derived from separating the reactions of glycolysis in the cytosol
from those that occur during the citric acid cycle in the mitochondrion.
Solution
Outer membrane of mitcochondria is a phospholipid bilayer. Outer membrane is permeable to
ions and molecules as it possess the proteins, porins in its structure of outer membrane. Inner
mitochondrial membrane is complex and permeable to water and gases only. Electron transport
chain and chmiosmosis occurs in inner mitochondrial membrane. Oxidative phosphorylation
involves in the production of a proton gradient through the passage of electrons from one
molecule to another. This proton gradient has been used in the production of ATP. If the inner
mitochondrial membrane like that of outer mitochondrial membrane also becomes porous to
ions, the oxygen cannot be able to accept electrons and cannot able to pick the protons to
produce the water at the end of electron transport chain. This results in a break in chemiosmosis
and a break in the production of ATP. NADH and FADH2 gets produced on inner mitochondrial
membrane due to its change in structure like that of outer mitochondrial membrane. But the
NADH and FADH2 cannot donate electrons and again both these cannot turn back into NAD
and FAD. Thus regeneration of electron carriers gets stopped. The pumping of H+ into
intermembrane space from matrix due to transfer of electrons from jhigher energy levels tolower
energy level produces the electrochemical gradient. Due to imprpper electron gradient, H+
pumping gets stopped from the matrix to the intermembrane space. Generally H+ is higher in
intermembrane space and lower in matrix when the energy has been produced, but due to a
change in structure of inner mitochondrial membrane, the H+ is higher in matrix and lower in
intermembrane space. This leads to lack of production of ATP due to unavailability of proton
gradient in the intermembrane space. Due to unavailability of reduced redox potentials NAD and
FAD, the processes of glycolysis and citric acid cycle gets impaired. Outer membrane of
mitochondria is a phospholipid bilayer. Outer membrane is permeable to ions and molecules as it
possess the proteins, porins in its structure of outer membrane. Inner mitochondrial membrane is
complex and permeable to water and gases only. Electron transport chain and chemiosmosis
occurs in inner mitochondrial membrane. Oxidative phosphorylation involves in the production
of a proton gradient through the passage of electrons from one molecule to another. This proton
gradient has been used in the production of ATP. If the inner mitochondrial membrane like that
of outer mitochondrial membrane also becomes porous to ions, the oxygen cannot be able to

2. accept electrons and cannot able to pick the protons to produce the water at the end of electron
transport chain. This results in a break in chemiosmosis and a break in the production of ATP.
NADH and FADH2 get produced on inner mitochondrial membrane due to its change in
structure like that of outer mitochondrial membrane. But the NADH and FADH2 cannot donate
electrons and again both these cannot turn back into NAD and FAD. Thus regeneration of
electron carriers gets stopped. The pumping of H+ into intermembrane space from matrix due to
transfer of electrons from higher energy levels to lower energy level produces the
electrochemical gradient. Due to improper electron gradient, H+ pumping gets stopped from the
matrix to the intermembrane space. Generally H+ is higher in intermembrane space and lower in
matrix when the energy has been produced, but due to a change in structure of inner
mitochondrial membrane, the H+ gets lack in matrix and thus lower H+ in intermembrane space.
This leads to lack of production of ATP due to unavailability of proton gradient in the
intermembrane space. Due to unavailability of reduced redox potentials NAD and FAD, the
processes of glycolysis and citric acid cycle get impaired, protein gradient cannot get established
and ATP production gets stopped.