Notes

1. Unit-1 Bioenergetics
TEJASVI NAVADHITAMASTU
“Let our (the teacher and the taught) learning be radiant”
Let our efforts at learning be luminous and filled with joy, and
endowed with the force of purpose
 pH, buffer and water in reaction to biological system.
 Bioenergetics – Concept of free energy and standard free energy.
 Biological oxidation-reduction reactions, redox potentials, relation between standard reduction
potentials and free energy change (derivations and numericals included).
 High energy phosphate compounds: introduction, phosphate group transfer, free
energy of hydrolysis of ATP and sugar phosphates.
 Porphyrins and cytochromes: Classification, structure and function

3. pH (potential of hydrogen) is a scale of acidity from 0 to
14. It tells how acidic or alkaline a substance is. More
acidic solutions have lower pH. More alkaline solutions
have higher pH. Substances that aren't acidic or alkaline
(called neutral solutions) usually have a pH of 7.

4. Applications
Buffer solutions are necessary to keep the correct pH for enzymes in many organisms to work. Many
enzymes work only under very precise conditions; if the pH moves outside of a narrow range, the enzymes
slow or stop working and can denature. In many cases denaturation can permanently disable their catalytic
activity.[3]
A buffer of carbonic acid (H2CO3) and bicarbonate (HCO3) is present in blood plasma, to maintain a pH
between 7.35 and 7.45.
Industrially, buffer solutions are used in fermentation processes and in setting the correct conditions for
dyes used in colouring fabrics.
They are also used in chemical analysis[2]and calibration of pH meters.
The majority of biological samples that are used in research are made in buffers, especially phosphate
buffered saline (PBS) at pH 7.4.
A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an aqueous solution
consisting of a mixture of a weak acid and its conjugate base, or vice versa.
Its pH changes very little when a small amount of strong acid or base is added to it.
Buffer

5. Buffer capacity
Buffer capacity, β, is a quantitative measure of the resistance of a buffer solution to pH change on
addition of hydroxide ions. It can be defined as follows

6. Henderson–Hasselbalch equation. In chemistry,
the Henderson–Hasselbalch
equation describes the derivation of pH as a
measure of acidity (using pKa, the negative log of
the acid dissociation constant) in biological and
chemical systems.

12. Gibbs free energy specifically refers to the energy associated with a chemical reaction that is available
after accounting for entropy. In other words, Gibbs free energy is usable energy or energy that is
available to do work.

19. Relation between Standard Reduction Potential and Free Energy Change

24. Phosphate Group Transfer

30. Biosynthesis
1. Formation of 8-aminolevulinat
2. Synthesis of porphobilinogen
3. Formation of porphyrin ring
4. Conversion of uroporphyrinogen lll to
protoporphyrin lX
5. Synthesis of heme from protoporphyrin lX