Transcript Major Metabolic Pathway

Major Metabolic Pathway
Dr. Saleha Shamsudin
Introduction to metabolism and
bioenergetics.
Glucose metabolism: Glycolysis and TCA
cycle,
Respiration.
Metabolism of nitrogenous compounds
and hydrocarbons.
Overview of biosynthesis for small and
macromolecules, anaerobic and autotrophic
metabolism
.
Major challenges in bioprocess development:
 To select an organism that can efficiently
make a given product
Before 1980 only naturally occurring organisms
were available (wild type organism).
With the advent of genetic engineering, it is
possible to remove or add genes to an
organism to alter its metabolic functions in a
predetermined manner (metabolic
engineering)
It is important to understand the metabolic
pathways in natural organisms either to use
them directly or to metabolically engineer
them to make a desired, novel product.
OR
Metabolic Pathways
M
: a complete set of chemical
reactions that occur in living cells, allowing
cells to grow and reproduce, maintain their
structures, and respond to their
environments.
OR
Characteristics of metabolism:
1. Varies from organisms to organism
2. Effected by environmental condition.
Even the same species may produce different product
when grown under different nutritional and environmental
regulation.
Example: Saccharomyces cerevisiae (baker’s yeast)
produces ethanol when grown under anaerobic
conditions. However, the major product is yeast cells
when growth conditions are aerobic. More over, even
under aerobic conditions at high glucose concentrations,
some ethanol production is observed. Which indicates
metabolic regulation not only by oxygen , but also by
glucose. This effect is known as the crabtree effect.
Therefore, control of metabolism is important in bioprocess
~
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produce energy to the cell
requires energy
glucose to glycogen
-Living cell require energy for biosynthesis,
transport of nutrient, motility and
maintainance.
-Energy is obtained from the catabolism of
carbon compounds (carbohydrate)
-Carbohydrates are synthesized from CO2
and H2O in the present of light by
photosynthesis.
the part of biochemistry concerned with the energy
involved in making and breaking of chemical
bonds in the molecules found in
biological organisms.
Bioenergetics
Sunlight
Autotrophs
or heterotrophs
Photosynthesis by autotrophs :
CO2 + H2O → carbohydrates
Catabolism
generating energy,
e.g ATP
Anabolism
requiring energy
Autotrophs and Heterotrophs
Organisms are divided into autotrophs and
heterotrophs according to their energy pathways.
Autotrophs are those organisms that are able to
make energy-containing organic molecules from
inorganic raw material by using basic energy
sources such as sunlight. Plants are the prime
example of autotrophs, using photosynthesis. All
other organisms must make use of food that comes
from other organisms in the form of fats,
carbohydrates and proteins. These organisms which
feed on others are called heterotrophs.
Three major categories of metabolic reactions:
(I) degradation of nutrients (II) Biosynthesis of small
molecules (III) Biosynthesis of large molecules
- Energy is mainly stored or transferred
by adenosine triphosphate (ATP) ~
(contains high-energy phosphate bonds)
Other energy carrying compounds
include GTP, UTP and CTP.
Glucose Catabolism
Glucose
Glycolysis or
Embden-Meyerhof-Parnas (EMP)
Aerobic metabolism
Anaerobic metabolism
Fermentation: ethanol,
acetic acid, lactate.
Tricarboxylic acid (TCA)
or (Krebs)
or (Citric acid cycle)
(pyruvate is converted to CO2 +NADH)
Oxidative phosphorylation