By...

Ram Lalji

Dagar Amit

David Arisa

Shelly Singh

Gurung Chena

Mac Kwan Kith

Patel shreyash

Nirjan Kathayat

Lopez Lah Nina A.

Keanne Uswawechmongkol

The Pathway of Glycolysis

The Pathway of Gluconeogenesis

It produces a net energy of 2ATP

It produces pyruvate which can enter into kreb’s cycle, capable of producing energy for the body.

Gluconeogenesis provides the body with energy, in times of fasting and severe hunger by converting lactate, glycerol and glucogenic amino acids to glucose for metabolism.

It keeps blood glucose level within critical limits. Thereby preventing death of erythrocytes and keeping normal functioning of brain.

The absence or deficiency of the enzyme pyruvate kinase can lead to the disease called hemolytic anemia.

Inhibition of glycolysis in cells severely depletes ATP and may result in apoptosis of cell(programmed cell death). NB: This malfunction is now studied as means of tackling cancer cells

Deficiency of the enzyme pyruvate carboxylase (converts pyruvate to oxaloacetate) in gluconeogenesis leads to the brain and red blood cells using up the glucose in the body which leads to HYPOGLYCEMIA.

Malfunctions in gluconeogenesis can also lead to lactic acidosis (high level of lactate acid in the body)

Glycolysis converts glucose to pyruvate.

-a 10-step biochemical pathway

-occurs in the cytoplasm

-2 molecules of pyruvate are formed

-net production of 2 ATP molecules by substrate-level phosphorylation

-2 NADH produced by the reduction of NAD+

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For glycolysis to continue, NADH must be recycled to NAD+ by either:

1. aerobic respiration – occurs when oxygen is available as the final electron acceptor

2. fermentation – occurs when oxygen is not available; an organic molecule is the final electron acceptor

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Hexokinase Phosphoglucose isomerase Phosphofructo kinase Aldolase Trios phosphate isomerase Glyceraldehyde phosphate dehydrogenase Phosphoglycerate kinase Phosphoglycerate mutase Enolase Pyruvate kinase

Glucose is the primary energy source for the brain, skeletal muscle, and red blood cells

Deficiency can impair the brain function

Gluconeogenesis is the synthesis of glucose from carbon atoms of noncarbohydrates

- required when glycogen stores are depleted

Carbon atoms for gluconeogenesis come from lactate, some amino acids, and glycerol, and are converted to pyruvate or other intermediates

Seven reactions are the reverse of glycolysis and use the same enzymes

3 glycolysis reactions are not reversible:

- reaction 1Hexokinase

- reaction 3Phosphofructokinase

- reaction10 Pyruvate kinase

Reversing the non-reversible reactions in glycolysis requires a high amount of energy

The cell therefore carries out a by pass reaction instead of a reverse of the non reversible reaction of glycolysis, making use of different enzymes i.e.

Pyruvate kinase- pyruvate carboxylase

Phosphofructo kinase-Fructose 1,6-biphosphate

Hexokinase- glucose 6 phosphate

A carbon is added to pyruvate to form

oxaloacetate by two reactions that replace the

reverse of reaction 10 of glycolysis

Then a carbon is removed, and a phosphate

added, to form phosphoenolpyruvate

Phosphoenolpyruvate is converted to fructose-

1,6-bisphosphate using the same enzymes in

glycolysis

A loss of a phosphate from fructose-1,6-bisphosphate forms fructose-6-phosphate and Pi

A reversible reaction converts fructose-6-phosphate to glucose-6-phosphate

The removal of phosphate from glucose-6-phosphate forms glucose

High glucose levels and insulin promote glycolysis

Low glucose levels and glucagon promote gluconeogenesis