Biosynthesis of carbohydrates

Assignment on topic Biosynthesis of Carbohydrate submitted to Institute of Environment and Sustainable Development, Banaras Hindu University.

1. Biosynthesis of
Carbohydrates
Presented by:
ShashankTripathi
M.Sc. (EnvironmetalBiotechnology)
Institute of environment & SustainalbleDevelopment
Banaras Hindu University
Varanasi-221005

2. What is Biosynthesis?
Themultistep,enzyme-catalysedprocess,where
substratesareconvertedintomorecomplex
productsinLivingBeings.
Theproductswhichareproducedasaresultof
biosynthesisarenecessaryforcellularand
metabolicprocessesdeemedessentialforsurvivalof
livings.

3. Topics to be cover:
Gluconeogenesis
Photosynthetic Carbohydrate Synthesis
Biosynthesis of Glycogen, Starch and Sucrose

4. Biosynthesis of Glucose
In animals Biosynthesis of Glucose take place through
Gluconeogenesis.
In plants Biosynthesis of Glucose take place through
Photosynthesis.

5. Biosynthesis of Glucose in
Animals:
•The Gluconeogenesis

6. Importance of Gluconeogenesis:
It is universal pathway found in all animals, plants,
Fungi and microorganisms for synthesis of glucose.
To maintain our blood glucose levels (prevent
hypoglycemia)
In vertebrates Gluconeogenesis in Liver and Kidney
provides glucose for use y the brain, muscles and
erythrocytes.

7. Process by which glucose is made from non-
carbohydrates:
Lactate
Pyruvate
Amino acids (particularly Ala)
Glycerol (from triacylglyceridehydrolysis) enters
as dihydroxyacetonephosphate
Acetate

8. Brain is top priority!
1.Needs large amounts of energy
2.2. Cannot store energy (very little glycogen storage)
3.3. Not sensitive to insulin regulation
4.4. Must have glucose for energy! Will not adapt to using
ketone bodies (fat) for energy until dire conditions arise
(weeks of fasting)

9. •The relevant features of the
pathway of gluconeogenesis
•Synthesis of glucose from
three and four carbon
precursors is essentially a
reversal ofglycolysis.

10. Net reaction:
2 pyruvate+2NADH+2ATP+2GTP+6 H2O + 2 H+
Glucose + 2 NAD+ + 4 ADP + 2 GDP + 6 Pi

11. Gluconeogenesis is not
simply reversal of
Glycolysis:
•Glycolysis is an ancient metabolic
pathway that is common to all forms
of cellular life, and can be performed
by all cells to obtain energy (a net of 2
ATP per glucose). In contrast,
gluconeogenesis is much more
specific; in humans, it is primarily
carried out in liver cells, as well as to
some extent in the adrenal cortex. It
also has a much more specific goal: to
produce glucose to be secreted into
the bloodstream when blood glucose
levels are low.
•The biochemical details of
gluconeogenesis are different from
those of glycolysis. The reason usually
given for this is that gluconeogenesis
needs to bypass the energetically
favorable/irreversible steps of
glycolysis.

12. Gluconeogenesis from Lactate:

13. Gluconeogenesis from Pyruvic Acid:

14. Gluconeogenesis is Energetically Costly:

15. Biosynthesis of Glucose in
Plants:
•The Photosynthesis

16. The Photosynthesis:
•Photosynthesis, theprocessby which
greenplantsand certain other
organisms transform light energy into
chemical energy.
Duringphotosynthesisin greenplants,
light energy is captured and used to
convert water, carbon dioxide, and
minerals into oxygen and energy-rich
organic compounds.
6CO
2+ 6H
2O ------> C
6H
12O
6+ 6O
2
Sunlight energy
Where: CO
2= carbon dioxide
H
2O = water
Light energy is required
C
6H
12O
6= glucose
O
2= oxygen

17. Comparative Pathway
from PEP to Glucose-6-
phosphate in Animals
and Plants :