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ALTERING OF NUTRIENTS AND METABLOISM

SUBMITTED BY :- KIRAN B.Sc. BIOTECH 6TH SEM

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METABOLISM Metabolism is the collection

of biochemical reactions that occur within a cell, which includes a tremendous diversity of molecular conversions.

Metabolic pathways can be divided into two broad types :-

Catabolism: The breakdown of molecules into smaller units. Energy is released in this process.

Ex: Glucose catabolism results in the release of CO2 and H2O Anabolism: The building of

compounds from small molecules into larger ones. Energy is used for this process to take place.

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GOAL OF METABOLISM _MAKE ATP Adenosine triphosphate, is referred to

as the “the energy of the cell” (cell energy) because it powers most of the reactions that take place in a cell.

each ATP molecule has three parts: an adenine molecule a ribose molecule three phosphate molecules in a chain The ATP is the molecule that carries

energy to the place where the energy is needed. When ATP breaks into ADP (Adenosine diphosphate) and Pi (phosphate), the breakdown of the last covalent link of phosphate (a simple -PO4) liberates energy that is used in reactions where it is needed.

ATP ADP + P + energy

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THE CAPTURE AND UTILIZATION OF ENERGY

As the sole building block of CARBOHYDRATES that are broken down during digestion and release energy .

glucose is a key molecule in the energy metabolism of both plants and animals. The free energy released by the complete oxidation of glucose is very large .

There are basically two stages in the catabolism of glucose, and they are virtually identical in all aerobic organisms.

The first stage glycolysis occurs in the soluble phase of the cytoplasm (the cytosol) and leads to the formation of pyruvate.

The second stage is the tricarboxylic acid (or TCA)cycle, which occurs within the mitochondria of eukaryotic cells and the cytosol of prokaryotes and leads to the final oxidation of the carbon atoms to carbon dioxide.

Most of the chemical energy of glucose is stored in the form of high- energy electrons, which are removed as substrate molecules are oxidized during both glycolysis and the TCA cycle.

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GLYCOLYSIS Glycolysis is a series of reactions that

and extract energy from glucose by splitting it into two three-carbon molecules called pyruvates.

Glycolysis – the first stage in cellular respiration:-

A series of enzyme catalyzed reactions.

Glucose converted to pyruvic acid. Small number of ATPs made (2 per

glucose molecule), but it is possible in the absence of oxygen.

All living organisms use glycolysis.

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STEPS INVOLVE IN GLYCOLYSIS Event 1 – Phosphorylation1) two phosphates added to glucose 2) requires ATP Event 2 – Splitting (cleavage) 6-carbon glucose split into two 3-carbon molecules Event 3 – Production of NADH

and ATP 1) hydrogen atoms are released 2) hydrogen atoms bind to NAD+ to produce NADH 3) NADH delivers hydrogen atoms to electron transport chain if oxygen is available 4) ADP is phosphorylated to become ATP 5)two molecules of pyruvic acid are produced

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Aerobic Reactions (Presence of Oxygen)–

• Pyruvic acid is used to produce acetyl CoA

• citric acid cycle begins• electron transport chain

functions• carbon dioxide and water are

formed• 36 molecules of ATP

produced per glucose molecule

Anaerobic Reactions (Absence of Oxygen) :-

• electron transport chain cannot accept NADH

• pyruvic acid is converted to lactic acid

• glycolysis is inhibited• ATP production declines

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CITRIC ACID CYCLE The 3-carbon pyruvate loses a carbon

producing an acetyl group. Electrons are transferred to NAD+

forming NADH. The acetyl group combines with CoA

forming Acetyl-CoA. Ready for use in Krebs cycle. begins when acetyl CoA combines with

oxaloacetic acid to produce citric acid citric acid is changed into oxaloacetic

acid through a series of reactions cycle repeats as long as pyruvic acid and

oxygen are available for each citric acid molecule: one ATP is produced eight hydrogen atoms are transferred to

NAD+ and FAD two CO2 produced

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ELECTRON TRANSPORT CHAIN (ETC) An electron transport chain (ETC) is a series of compounds

that transfer electrons from electron donors to electron acceptors via redox (both reduction and oxidation occurring simultaneously) reactions, and couples this electron transfer with the transfer of protons (H+ ions) across a membrane.

So far only 4 of the 38 ATP that will be produced have been, all by substrate level phosphorylation.

The remaining will be produced by the ETC. The majority of the ATP produced comes from the energy

carried in the electrons of NADH (and FADH2) that were produced by the Krebs Cycle. 6 NADH and 2 FADH2

The energy in these electrons is used in the ETC to power the synthesis of ATP.

There are thousands of ETC’s found in each mitochondria, which can number in the 100’s depending on the cell type.

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PRODUCING ATP- CHEMIOSMOSIS

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REFERENCES

Cell biology by karp https://www.slideshare.net/ https://www.khanacademy.org/