1. UNIT I : BIOMOLECULES AND
BIOENERGETICS
TOPIC TO BE DISCUSSED UNDER THIS ACC. TO
SYLLABUS:
Biomoleules
Proteins and amino acids
Introduction to proteins
Functions of proteins
Amino acids classification
Structure of proteins
Bioenergetics
Concept of free energy, endergonic and exergonic reaction,
Relationship between free energy,
enthalpy and entropy; Redox potential.
Energy rich compounds; classification; biological significances of ATP and
cyclic AMP
8. Endergonic Reactions
Chemical reaction that
requires a net input of
energy.
Photosynthesis SUN
Light
Energy
photons
6CO2 + 6H2O C6H12O6 + 6O2
(glucose)
10. Free energy
The energy actually available to do work
is , known as free energy.Changes in
the fiee energy (AG) are valuable in predicting
the feasibility of chemical reactions. The
Reactions can occur spontaneously if they are
accompanied by decrease in free energy.
11. GIBBS HELMOLOTZ EQUATION
During a chemical reaction, heat may be released or absorbed.
Enthalpy (∆H) is a measure of the change in heat content of
the reactants, compared to products.
Entropy (∆S) represents a change in the randomness or d
isorder of reactants ano products. Entropy attains a maximum
as the react iona pproachese qui l ibr ium.T he react ions of
biological systems involve a temporary decrease in entropy.
The relation between the changes of free energy (∆G),
enthalpy (∆H) and entropy (∆S) is exoressed as
∆G= ∆H-T∆S
T representsth e absolutet emperaturei n Kelvin
(K=273+₀C).
The term standard free energy represented by ∆G' (note the
superscript') is often used. ∆ indicates the free energy
change when the reactantso r productsa re at a concentration
of 1 mol/l at pH 7.0.
14. Two Types of Metabolism
Anabolic
Pathways
Catabolic
Pathways
15. Anabolic Pathway
Metabolic reactions, which
consume energy (endergonic), to
build complicated molecules from
simpler compounds.
Photosynthesis SUN
light
energy
6CO2 + 6H2O C6H12O6 + 6O2
(glucose)
16. Catabolic Pathway
Metabolic reactions which release
energy (exergonic) by breaking
down complex molecules in simpler
compounds
ATP
Cellular Respiration
C6H12O6 + 6O2 6CO2 + 6H2O +
(glucose)
energy
21. ATP Can be synthesizedin two ways
1. Oxidative phosphorylation : This is the major source of ATP
in aerobic organisms. lt is linked with the mitochondrial
electron transport chain .
2.Substrate level phosphorylation : ATP may be directly
synthesized during substrate oxidation in the metabolism. The
high-energy compounds such as phosphoenolpyruvate and 1,3-
bisphosphoglycerate(intermediates of glycolysis) and succinyl
Co-A (of citric acid cycle) can transfer high-energy phosphate to
ultimately produce ATP.
22. ATP-ADP cycle
ATP serves as an immediatelv available energy currency of the cell which is
constantly being utilized and regenerated. This is Represented b y ATP-ADP
cycle, the fundamental basis of energy exchange reactions in living system .
The turnover of ATP is very high.
23. ATP acts as an energy link
between the catabolism
(degradation of molecules) and
anabolism( synthesis)n the
biological system.
24. Breaking the Bonds of ATP
Process is called
phosphorylation
Occurs continually
in cells
Enzyme ATP-ase
can weaken &
break last PO4
bond releasing
energy & free PO4
25. How does ATP work ?
Organisms use enzymes to
break down energy-rich
glucose to release its
potential energy
This energy is trapped and
stored in the form of
adenosine triphosphate(ATP)
26. How Much ATP Do Cells Use?
It is estimated
that each cell
will generate
and consume
approximately
10,000,000
molecules of
ATP per second
27. Coupled Reaction - ATP
The exergonic
hydrolysis of ATP
is coupled with
the endergonic
dehydration
process by
transferring a
phosphate group
to another
molecule.
H2O
20
H2O
28. Hydrolysis of ATP
ATP + H2O ADP + P
(exergonic)
Adenosine triphosphate (ATP)
P P P
Hydrolysis
(add water)
P P P
+
Adenosine diphosphate (ADP)
