Introduction to Introduction to BiochemistryBiochemistry

By

Dr Khaled Saleh Algariri

What are seven characteristics What are seven characteristics of ALL living things of ALL living things

1. Living things require food for energy 2. Living things respire (take in oxygen gas to breakdown food for energy) 3. Living things respond to the environment 4. Living things produce waste 5. Living things are able to repair themselves 6. Living things grow and reproduce 7. Living things have a limited lifespan

BiomoleculesBiomolecules

Carbohydrates Lipids Proteins Nucleic acid

CarbohydratesCarbohydrates

Composed of carbon, hydrogen, and oxygen. Sugars Monosaccharides

– Ex. Glucose

Disaccharides– Ex. Sucrose

Polysaccharides– Ex. Glycogen, Peptidoglycan

Carbohydrate - GlucoseCarbohydrate - Glucose

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Carbohydrate - SucroseCarbohydrate - Sucrose

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Carbohydrate - PeptidoglycanCarbohydrate - Peptidoglycan

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Carbohydrate - GlycogenCarbohydrate - Glycogen

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Carbohydrates most abundant organic molecule Carbohydrates most abundant organic molecule found in nature. found in nature.Initially synthesized in plants from a complex seriesInitially synthesized in plants from a complex series of reactions involving photosynthesis. of reactions involving photosynthesis.Basic unit is monosaccharides.Basic unit is monosaccharides.Monosaccharides can form larger molecules e.g. Monosaccharides can form larger molecules e.g. glycogen, plant starch or cellulose.glycogen, plant starch or cellulose.

FunctionsFunctionsStore energy in the form of starch (photosynthesis Store energy in the form of starch (photosynthesis in plants) or glycogen (in animals and humans).in plants) or glycogen (in animals and humans).Provide energy through metabolism pathways and Provide energy through metabolism pathways and cycles.cycles.Supply carbon for synthesis of other compounds.Supply carbon for synthesis of other compounds.Form structural components in cells and tissues. Form structural components in cells and tissues. Intercellular communicationsIntercellular communications

LipidsLipidsFatty Acids

– The building blocks of lipids.

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LipidsLipidsExamples are:

– Waxes– Fats and oils– Phospholipids– Steroids

Phospholipid Cell Membrane.

Fatty acids : Are monocarboxylic acid contains even number C

atoms

Two types: saturated (C-C sb) and unsaturated (C-C db)

Fatty acids are components of several lipid molecules.

E,g. of lipids are triacylglycerol, steriods (cholestrol, sex hormones), fat soluble vitamins.

Functions Storage of energy in the form of fat Membrane structures Insulation (thermal blanket) Synthesis of hormones

ProteinsProteins

Made up of polymers of amino acids.

“beads on a string.” 20 primary amino

acids exist. A polymer of 3 or

more amino acids forms a polypeptide.

ProteinsProteins

Primary Structure– Linear sequence of amino acids.

Secondary Structure– Form helices or sheets due to their structure.

Tertiary Structure– A folded protein.

Quaternary Structure– 2 or more polypeptide chains bonded together.

Amino acids:

• Building blocks of proteins.

• R Group (side chains) determines the chemical properties of each amino acids.

• Also determines how the protein folds and its biological function.

• Functions as transport proteins, structural proteins, enzymes, antibodies, cell receptors.

EnzymesEnzymes Are proteins. Are considered

biological catalysts.– Speed up a chemical

reaction without being altered.

Names often end in “-ase.”– Ex. Lipase,

carbohydrase. Act on a substrate. Proteins, including

enzymes, can be denatured.

Nucleic AcidsNucleic Acids

DNA and RNA.– (DNA - deoxyribonucleic acid,

RNA - ribonucleic acid).Is the “hereditary molecule.”Contains genes that code for a certain

product.DNA is translated into RNA which is used

to produce a protein or other product.

Nucleic Acid StructureNucleic Acid Structure

DNA nucleotides– Building blocks of DNA.

RNA nucleotides– Building blocks of RNA.

Nucleic Acid StructureNucleic Acid Structure

DNA– Nitrogenous base– Deoxyribose– Phosphate group

RNA– Nitrogenous base– Ribose– Phosphate group

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Nitrogenous BasesNitrogenous Bases

Adenine (A) Guanine (G)Cytosine (C)Thymine (T) – only DNAUracil (U) – only RNA

DNA and RNA

Nitrogenous BasesNitrogenous Bases

A and G – Purines (double-

ring structures)

C, T, and U– Pyrimidines

(single-ring structures)

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METABOLISM• The vital activity of a living organism is determined by The vital activity of a living organism is determined by

– the specific organization of biological structures, the specific organization of biological structures, – metabolic processes, metabolic processes, – energy metabolism, energy metabolism, – genetic information transfer, genetic information transfer, – regulatory metabolism regulatory metabolism

• The damage of any of these links develops a pathological process and a The damage of any of these links develops a pathological process and a disease.disease.

• An understanding of the molecular mechanisms involved in the vital An understanding of the molecular mechanisms involved in the vital activity or malfunction of the organism constitutes the basis for the search activity or malfunction of the organism constitutes the basis for the search and clinical applicationsand clinical applications

In the living organism there are:In the living organism there are:• Exogenous metabolism – extracellular transformations of the materials on Exogenous metabolism – extracellular transformations of the materials on

the way to their uptake and excretion from the cellsthe way to their uptake and excretion from the cells• Intermediary metabolism – the sum of all chemical reactions that occur in Intermediary metabolism – the sum of all chemical reactions that occur in

the living cellthe living cell

Four major processes are involved:Four major processes are involved:

1.1. Accumulation of energy from the decomposition of compoundsAccumulation of energy from the decomposition of compounds

2.2. Utilization of energy for Utilization of energy for • the synthesis of essential molecular components (monomers, the synthesis of essential molecular components (monomers,

macromolecules) and macromolecules) and

• the performance of osmotic, electric or mechanical work.the performance of osmotic, electric or mechanical work.

3.3. Decomposition of renewable structural components of the cellDecomposition of renewable structural components of the cell

4.4. Synthesis and decomposition of specialized biological molecules Synthesis and decomposition of specialized biological molecules (hormones, mediators, cofactors etc.)(hormones, mediators, cofactors etc.)

METABOLISMMETABOLISMTwo processes are distinguished:Two processes are distinguished:• catabolismcatabolism - the sum of degradative processes leading to cleavage of large - the sum of degradative processes leading to cleavage of large

molecules into smaller ones, with release of energy (stored as ATP), andmolecules into smaller ones, with release of energy (stored as ATP), and

• anabolismanabolism – the sum of processes leading to the synthesis of complex – the sum of processes leading to the synthesis of complex molecules from simpler ones, with the comsumption of energy (as ATP)molecules from simpler ones, with the comsumption of energy (as ATP)

ATP is a coupling energetic link between the two metabolic pathways.ATP is a coupling energetic link between the two metabolic pathways.Other simple metabolites, formed by the catabolic pathway, are starting Other simple metabolites, formed by the catabolic pathway, are starting

metabolites for the synthesis of monomers or macromolecules in the metabolites for the synthesis of monomers or macromolecules in the anabolic pathway. anabolic pathway.

This cycle unifying the degradative and synthetic routes is called This cycle unifying the degradative and synthetic routes is called amphibolic pathwayamphibolic pathway

The anabolism and catabolism are The anabolism and catabolism are separated in spaceseparated in space..All the processes in the living organisms are All the processes in the living organisms are enenzymatic processeszymatic processes

SPECIFIC FEATURES OF METABOLISMSPECIFIC FEATURES OF METABOLISM

CATABOLISM ANABOLISM

Degradative processes Biosynthesis processes

Cleavage of large molecules into smaller ones

Synthesis of complex molecules from simpler ones

Release of energy Consumption of energy

Oxidative reactions Reductive reactions

Use of oxidized coenzymes: NAD+, NADP+, FAD

Use of reduced coenzymes:NADH+H+, NADPH+H+, FADH2

Some metabolites which result from catabolism can be used for the anabolism and conversely

All chemical processes proceed with the involvement of enzymes, being regulated by alloster and feed-back mechanism

The EndThe EndThanksThanks