Gluconeogenesis is the metabolic pathway that results in the generation of glucose from non-carbohydrate substrates like amino acids, lactate, pyruvate, and glycerol. It ensures the maintenance of appropriate blood glucose levels during periods of fasting or low carbohydrate intake when liver glycogen is depleted. Gluconeogenesis is important because it produces the energy-giving fuel glucose when carbohydrate substrates are insufficient, such as during starvation, low-carbohydrate diets, or intense exercise. The pathway of gluconeogenesis involves reversing the reactions of glycolysis using different enzymes to synthesize glucose, primarily in the liver and kidneys.

1. Gluconeogenesis
Honey’s Group Presenting

2. Gluconeogenesis Is presenting by
Shehbaz
Unified by
Muhammad Irfan
Syed Safeer Mehdi Bukhari
Shehbaz
GCUF Pakistan

3. Gluconeogenesis
The literal meaning of
Gluconeogenesis is
GLUCO – glucose;
NEO – new;
GENESIS – creation.

4. Defination:
 Gluconeogenesis (GNG) is a Metabolic
pathway that results in the generation
of glucose from certain non-carbohydrate carbon
substrates including Amino acids,Lactate, Pyruvate
and Glycerol.
OR
 Gluconeogenesis is a biochemical term that
describes the synthesis of glucose or glycogen from
substances which are not carbohydrates like
Glycogen

5. Why is Gluconeogenesis important?
 Gluconeogenesis is the procedure that
generates the energy giving fuel ’
glucose’ from substances other than
carbohydrates, which are stored in the
body , When the carbohydrate substrates
are not sufficiently available as in
starvation or when they are of great
demand as in intense physical
exertion(an expenditure of physical and
mental effort).

6.  It occurs in all microorganisms, fungi, plants and
animals and the reactions are essentially the same,
leading to the synthesis of one glucose molecule from
two pyruvate molecules.
 It Ensures the maintenance of appropriate blood
glucose levels (3.3 to 5.5 mmol/L) when the liver
Glycogen is almost depleted and no carbohydrates
are ingested
 If Glucose level falls below 2 mmol/L, Unconsiousness
(Coma) occurs.

7.  After about 18 hours of fasting or during intense or
prolonged exercise,Glycogen stores are depleted and
may become insufficient .At that point, if no
carbohydrates are ingested,Gluconeogenesis become
important.
 This process occurs during periods
of fasting, starvation, low-carbohydrate diets, or
intense exercise

8. Gluconeogenesis Pathway
Basically Gluconeogenesis is the reversal of Glycolysis(which is
the process of breaking down of glucose to produce energy)
Glycolysis go forward to another energy cycle called Citric acid
cycle by forming a substance called pyruvate. So,
Gluconeogenesis is just the reversal of Glycolysis – starting with
pyruvate.
There are 10 reactions involved in Gluconeogenesis,Seven are
shared with Glycolysis,these seven reactions have delta-
G(Change in Gibs Free energy that can be used to do work)
close to zero and that’s why they are reversible

10. Difference b/w Glycolysis and
Gluconeogenesis
 The main reactant which begins the Glucose synthesis in
Gluconeogenesis is Pyruvate,and Pyruvate is the end
product of Glycolysis.
 There are three steps difference in both the process
which are catalyzed by different Enzymes
 Site of pathway of glycolysis is liver and
muscles.While Gluconeogenesis occurs in liver
(90%) and kidneys (10%)

11.  Glycolysis has two types Anaerobic and aerobic
glycolysis,while gluconeogenesis has not any sub-
types
 ATP Production: ATPs are produced in Glycolysis
while no ATPs are produced in Gluconeogenesis (It
only produced Glucose as it end Product)

12. Substrates of Gluconeogenesis
 Glucogenic amino acids (that can be converted into glucose
by gluconeogenesis) amino acids like alanine and glutamine

 Lactate(HydroxyPropanoic acid C3H6O3) (Anions of lactic
acid) which is produced as a byproduct of glycolysis(by
anaerobically) in muscles, red blood cells etc
 Glycerol, from breakdown of Lipids (such as triglycerides)stored in adipose tissue

13.  . Interesting Thing; Not all the amino acids are totally
Glucogenic or ketogenic There are five amino acids that
act as Both Glucogenic and ketogenic (Whose
catabolism produce acetyl_CoA and not Glucose),These
are
 Isoleucine
 Phenylalanine
 Tyrosine
 Threonine
 Tryptophan

14. Conversion of glucogenic amino acids
into Glucose

15. Lactate conversion into Glucose
Muscular activities and anaerobic glycolysis in red blood cells produce a large
amount of lactate. This lactate is taken up by the liver and gets converted to
pyruvate by the enzyme lactate dehydrogenase. Pyruvate then gets
converted to glucose by hepatic Gluconeogenesis which is then sent back to
muscles for reuse. This is known as Cori cycle

16. Conversion of Glycerol into Glucose
Glycerol is formed by breaking down of
triacylglecerol in the fatty tissue. It is then
carried to the liver where it gets converted to
pyruvate and enters Gluconeogenesis.
During Prolonged fasting, glycerol is the major
Glucogenic precursor,accounting for about 20%
of glucose production

17. Finish…!!!