Introduction to Biochemistry Dr.S.Chakravarty M.D.

Don’t fall behind..

• If you read what I am teaching today, you need just 30 mins to revise the topic and solve mcqs.

• If you don’t read for three days ….you will need 2 days to cover a topic and BY THEN I’ll have finished another 2 topics already…..

• Biochemistry is a LOT OF UNDERSTANDING AND A LOT OF MEMORIZATION too…..

WHY ? Any chemistry is VOLATILE …revision is the KEY

BOOKS for MD2

• Lippincott or Harper ( good for metabolism!)• Kaplan Step 1 Lecture notes :- Mol .Biology and

Genetics

• MCQs- good sources– PRE-TEST BIOCHEMISTRY AND GENETICS– BRS QUESTION BANK– USMLE WORLD Q.BANK– KAPLAN Q.BANK

BASIC RULES

• Switch off MOBILES • Don’t come late – You’ll be not be allowed to enter after 5 minutes.

• No edibles • No blowing/bubbling of chewing gums

INTERNAL ASSESSMENT

• FINAL DISTRIBUTION – (30% BLOCK 1) + (30% BLOCK 1)+ (30% NBME )+ 10 %

internal assessment

INTERNAL ASSESSMENT means :-(10% block 1 + 10 % block 2 + 10% class performance)

Class performance ( 10%)

– 30% CLASS QUIZZES – 20% CLASS ASSIGNMENTS – 50% SMALL GROUP & CLINICAL CASE DISCUSSION

PERFORMANCE

Introduction to Biochemistry Dr. Soumitra ChakravartyMBBS,MD.

BIOCHEMISTRY

BIO ( Greek, from bios) +

CHEMISTRY

So, what is life ?

What is the purpose of life ?

The purpose of life is a life full of purpose. .

Need an official definition ??

Life :- The condition that distinguishes animals and plants from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally.

Life needs 3 things….

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(1) ENERGY, which it must know how to:

• Extract

• Transform

• Utilize

Digestion and Oxidation of food

Reducing equivalents

ATP

ENERGY !!

BIOLOGICAL

OXIDATION

ATP is the energy currency of the cell!

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Life needs …

(2) SIMPLE MOLECULES, which it must know how to:

• Convert• Polymerize• Degrade

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Macromolecules

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Macromolecules

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Biomolecules – Structure

• Building block• Simple sugar• Amino acid• Nucleotide• Fatty acid

• Macromolecule• Polysaccharide• Protein (peptide)• RNA or DNA• Lipid

Anabolic pathways

CatabolicPathways

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How did organic complex molecules evolved from more simple molecules?

• Urea was synthesized by heating the inorganic compound ammonium cyanate (1828)

• This showed that compounds found exclusively in living organisms could be synthesized from common inorganic substances

The Urey-Miller experiment (1950)

Some amino acids could be produced:

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Why is potassium concentration more inside a cell than outside ?

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Life needs …

(3) CHEMICAL MECHANISMS, to:

• Harness energy• Drive sequential chemical reactions• Synthesize & degrade macromolecules• Maintain a dynamic steady state• Self-assemble complex structures• Replicate accurately & efficiently• Maintain biochemical “order” vs outside

THE METABOLIC REACTIONS ARE SIMILARIN ALL LIFE FORMS………

• ANATOMY :- ( Greek ἀνατομία anatomia, from ἀνατέμνειν ana: separate, apart from, and temnein, to cut up, cut open) is a branch of biology and medicine that is the consideration of the structure of living things.

• PHYSIOLOGY:- The science of the function of living systems showing how organisms, organ systems and organs carry out the chemical or physical functions that exist in a living system.

BIOCHEMISTRY• Biochemistry can also be described as the

science of the chemical constituents of living cells and of the reactions and processes they undergo.

• The Aim of Biochemistry Is to Describe & Explain, in Molecular Terms, All Chemical Processes of Living Cells.

Modern Biochemistry

A Knowledge of Biochemistry Is essential to All Life Sciences.

Biochemistry includes the sciences of :-

•MOLECULAR BIOLOGY•MOLECULAR DIAGNOSTICS•IMMUNOCHEMISTRY•NEUROCHEMISTRY•BIOINORGANIC, BIOORGANIC, AND BIOPHYSICAL CHEMISTRY.•LABORATORY DIAGNOSIS•THERAPY – ALMOST EVERYWHERE

Normal Biochemical Processes Are the Basis of Health

Biochemical Research Has Impact on Nutrition & Preventive Medicine.– One major prerequisite for the maintenance of health is

that there be optimal dietary intake of a number of chemicals;• vitamins, • certain amino acids, • certain fatty acids, • various minerals, • and water.

– Preventive medicine largely focuses on providing these in adequate amounts.

Most & Perhaps All Diseases Have a Biochemical Basis

The Major Causes of Diseases

1. Physical agents: Mechanical trauma, extremes of temperature, sudden changes in atmospheric pressure, radiation, electric shock. 2. Chemical agents, including drugs: Certain toxic compounds, therapeutic drugs, etc.

3. Biologic agents: Viruses, bacteria, fungi, higher forms of parasites.

4. Oxygen lack: Loss of blood supply, depletion of the oxygen-carrying capacity of the blood, poisoning of the oxidative enzymes.5. Genetic disorders: Congenital, molecular.

6. Immunologic reactions: Anaphylaxis, autoimmune disease.

7. Nutritional imbalances: Deficiencies, excesses.

8. Endocrine imbalances: Hormonal deficiencies, excesses.

Some Uses of Biochemical Investigations and Laboratory Tests in Relation to Diseases

Use Example1. To reveal the fundamental causes and mechanisms of diseases

Demonstration of the nature of the genetic defects in Phenylketonuria.

2. To suggest rational treatments of diseases based on item 1 above

A diet low in phenylalanine for treatment of phenylketonuria.

3. To assist in the diagnosis of specific diseases Use of the plasma levels of troponin I or T in the diagnosis of myocardial infarction.

4. To act as screening tests for the early diagnosis of certain diseases

Use of measurement of blood thyroxine or thyroid-stimulating hormone (TSH) in the neonatal diagnosis of congenital hypothyroidism.

5. To assist in monitoring the progress (ie, recovery, worsening, remission, or relapse) of certain diseases

Use of the plasma enzyme alanine aminotransferase (ALT) in monitoring the progress of infectious hepatitis.

6. To assist in assessing the response of diseases to therapy

Use of measurement of blood carcinoembryonic antigen (CEA) in certain patients who have been treated for cancer of the colon.

BIOCHEMISTRY AND PHARMACOOGY /TOXICOLOGY

• ALL DRUGS ARE MOSTLY COMPETETIVE INHIBITORS OF MANY BODY ENZYMES .

• MOST TOXINS ARE NON –COMPETETIVE INHIBITORS OF THE BODY ENZYMES.

Human Genome Project (HGP)

• Completed in 2003, the Human Genome Project (HGP) was a 13-year project coordinated by the U.S. Department of Energy and the National Institutes of Health.

Is it enough?

PROTEOMICS !!

1. Average no of genes is 40,000- 60, 000, average no . of proteins is more than ½ a million in humans.

2. Average no of proteins per gene -- one to two in bacteria, three in yeast three to six per gene ,in human beings .

3. In addition to genetic makeup , many other factors determine proteins behavior and expression- factors like pH, oxygen depletion , chemicals and drugs etc.

THE ‘OMICS

• GENOMICS• TRANSCRIPTOMICS• PROTEOMICS• METABOLOMICS• GLYCOMICS• LIPIDOMICS• NUTRIGENOMICS• PHARMACOGENOMICS …..and of course BIOINFORMATICS!!

Thank you