CLASSIFICATION OF CARBOHYDRATESCLASSIFICATION OF CARBOHYDRATES

GLUCOSEGALACTOSE

MALTOSELACTOSESUCROSE

STARCHGLYCOGENCELLULOSE

FRUCTOSE

STARCH, GLYCOGEN & CELLULOSESTARCH, GLYCOGEN & CELLULOSE

Polysaccharides are ubiquitous in nature.Polysaccharides are ubiquitous in nature.

They are called They are called HomopolysaccharidesHomopolysaccharides, when made from same sugars and , when made from same sugars and HeteropolysaccharidesHeteropolysaccharides when made from different sugars. when made from different sugars.

They can be linear or branched. Linear chains are made of They can be linear or branched. Linear chains are made of α-1→4 bonds and α-1→4 bonds and branch is made of α-1→6 bondsbranch is made of α-1→6 bonds

STARCH• Is a storage polysaccharide in Plants• MADE OF α – GLUCOSE. • AMYLOSE – Linear, linked by α 1→ 4 bonds. [15 – 20%].• AMYLOPECTIN – Branched, linked by α 1→ 6 bonds. [80 – 85%]• Branch point after every 30 Glc unit.

GLYCOGEN

• Storage polysacc in animals, highly branched. Similar to Amylopectin

• Branch point every 8 – 12 Glc units• Has only 1 reducing end but many non-reducing ends

CELLULOSE

• Similar to Amylose, linear but made of β 1→ 4 bonds.• Very long chains – 15,000 – 20,000 Glc units• Can’t be digested because amylase recognises only ‘α’ bonds• Microorganism in gut Trichonympha secretes cellulase, which

breaks down cellulose to short chain FA, a energy source

METABOLISM

PRIMARY FUNCTIONS:• Acquiring and Utilising Energy• Synthesis of structural components of cell eg Membrane• Growth & Development• Removal of waste products

Co-ordinated and specific reactions – organised as PATHWAYS…

GENERAL CHARACTERISTIC – of BIOCHEMICAL REACTIONS: No. of reaction types are few – eg., Hydrolysis, Oxidation-reduction etc. One enzyme usually catalyses only One reaction Only a few important pathways inside cell – Glycolysis, Gluconeogenesis, TCA cycle, Urea cycle, β-Oxidation etc.

Anabolic and Catabolic Pathways

CARBOHYDRATES METABOLISM

• Glycolysis is a Amphibolic pathway• It occurs in Eukaryotes & Prokaryotes• It occurs in cytoplasm of cell• Total 10 reactions in 2 phases• End product depends on presence of O2

GLYCOLYSIS

Prep

arat

ory

Pay

Off

ENERGETICS:

2 ATP

2 NADH = 6ATP

ENERGETICS:

2 ATP

2 NADH = 6ATP

GLUCONEOGENESIS

Pyruvate Carboxylase & PEP Carboxykinase function inside mitochondria

CORI CYCLE

HMP Shunt

AIM:1.To produce NADPH, involved in biosynthetic reactions2.To produce Ribose-5-P, a precursor for DNA synthesis

HMP Shunt

SUMMARY

1) Phase – I NADPH & Rib-5-P produced

2) Phase – II Transketolase & Transaldolase involved

Phas

e I

Phas

e II

TCA CYCLE• Final pathway for oxidation of CHO, PTN & Lipid• Occurs in Mitochondrial Matrix• End product is Acetyl CoA• Series of dehydrogenation & decarboxylation rxns• Each cycle generates 12 ATP’s• It is amphibolic in nature

FORMATION OF ACETYL COA:

ENERGETICS:

2 NADH = 6 ATP

ENERGETICS:

2 NADH = 6 ATP

TCA CYCLE

CITRATE SYNTHASECITRATE SYNTHASEACONITASEACONITASE

ISOCITRATE dehydrogenaseISOCITRATE dehydrogenase

KETO GLUTARATE dehydrogenaseKETO GLUTARATE dehydrogenase

SUCCINATE THIOKINASESUCCINATE THIOKINASE

SUCCINATE dhaseSUCCINATE dhase

FUMARASEFUMARASE

MALATE dhaseMALATE dhase

ENERGETICS:

3 NADH = 9ATP

1 FADH2 = 2 ATP

1 GTP = 1 ATP

-----------------------

TOTAL = 12 ATP

ENERGETICS:

3 NADH = 9ATP

1 FADH2 = 2 ATP

1 GTP = 1 ATP

-----------------------

TOTAL = 12 ATP

GLUCOSE OXIDATION:

GLYCOLYSIS = 8 ATP

ACETYL CO-A = 6 ATP

TCA CYCLE = 24 ATP

-----------------------

TOTAL = 38 ATP

GLUCOSE OXIDATION:

GLYCOLYSIS = 8 ATP

ACETYL CO-A = 6 ATP

TCA CYCLE = 24 ATP

-----------------------

TOTAL = 38 ATP

AMPHIBOLIC NATURE

GLYOXYLATE CYCLEMAIN FEATURES:• A modified form of TCA cycle• Occurs in Plants – during Germination stage• Helps to form Glucose from Lipid stores• Key enzymes – Isocitrate Lyase & Malate synthase present inside Glyoxysomes.• Involves participation of 3 compartments inside cell; glyoxysomes, mitochondria & cytosol

• Occurs from non-reducing end.• Takes place in muscle & liver• Glucose units enter glycolysis by the help of 3 enz:-

Glycogen phosphorylaseGlycogen debranching enzymePhosphogluco mutase

GLYCOGENOLYSIS

GLYCOGEN

GLUCOSE – 1 – P

GLUCOSE – 6 – P

GLYCOGEN

GLUCOSE – 1 – P

GLUCOSE – 6 – P

GLYCOGENOLYSIS

Glycogen debranching enz reaction• Acts at a branch point when it’s 4 glc long.• Transfers a 3 glc unit from branch point to a longer chain for p’lase action to continue• Last glc residue at branch removed as well

Phosphogluco mutase reactionGlc-1-P → Glc-6-P

GLYCOGENESIS• Starts when UDP-Glc & Glycogenin are available.• 4 enz involved:-

a) Phosphogluco mutase Glc-6-P → Glc-1-P b) UDP-glucose pyrophosphorylase

Glc-1-P + UTP → UDP-glc + PPi

c) Glycogen synthase – Transfers glc to non- reducing end. Acts until branch is 11 unit long

d) Glycogen branching enzyme – Transfers 6 or 7 glc from a branch containing 11 glc units to a more interior position creating a new branch.

c) Glycogen synthase – Transfers glc to non-reducing end. Acts until branch is 11 unit long

GLYCOGENESIS

d) Glycogen branching enzyme – Transfers 6 or 7 glc from a branch with 11 glc units to a more interior position creating a new branch.

GLYCOGENESIS