(dr. saleem) overview of metabolism & bioenergetics i

We have indeed created man in the best shape(Holy Quran)

Lecture # 1 BiochemistryFoundation Module

November-2010

Aims of Medical Sciences

To obtain the Knowledge of:Normal pattern of life.Abnormalities of life (Diseases).Procedures to prevent Diseases.Procedures to treat Diseases.

What life means to a Biologist?A variety of thoughts about life.Criteria of life:

Definite capability to grow.Increase in size.Increase in weight.

Reproduction.

Cells are made up of Specific Chemical

Compounds

Different components of cells such as

cytoplasm, nucleus, and cell membrane

are made up of specific chemical

compounds

An uncountable variety ofchemical compounds are related to

life, e.g., Bacteria may containover 5000 varieties.

Familiar examples in human body:Proteins (Haemoglobin, Collagen, Keratin, Albumin etc.). Carbohydrates (Glucose, Ribose, Chondrotin, Heparin etc.)Nucleic acids.Lipids.

Growth and Reproduction are based on Chemical Compounds and Reactions Chemical Compounds:

Proportional arrangement of specific chemical compounds.

Chemical Reactions:Synthesis of necessary compounds.Production of necessary energy.

Biological Concept of LifeLife is a biologic phenomena in which:

Certain specific chemical compounds are present in a definite proportion and in a planned manner.Still further hundreds of planned reactions are involved in growth and reproduction.

Basis of Health - Disease - Death

HEALTHSo long the chemical reactions are not

disturbed system remains healthy.DISEASE

Alterations within certain limit doesn’t kill the system but make it abnormal

(disease).DEATH

Changes beyond a limit ceases whole process and the system is dead.

Aim of studying Biochemistry?Understanding the normal pattern of life:

To get a sound knowledge of chemical compounds and reactions related to life.

Understanding the diseases:To know what, when, how & why abnormal changes takes place (Environmental, Nutritional, Genetic).

Diagnose & Treatment of diseases:To know how these changes can be prevented & corrected.

Hundreds of plannedchemical reactions

are involved in life process

Oxidation of compounds to generate energy e.g., Glucose, Fats etc.Synthesis of compounds necessary for

life e.g., Proteins, Nucleic Acids Hormones, Cholesterol etc.

A Chemical Reaction Taking Place

In Living Cell is CalledMetabolic Reaction.

Two types of metabolic reactions On the basis of final outcome:Anabolic Reactions.Catabolic Reactions.

Anabolic Reactions build up the tissues

Synthesis of higher and complex biological compounds from smaller molecules e.g., synthesis of proteins from Amino acids.Result in synthesis of complex

molecules and build up of tissues.Energy consuming reactions. Dominant during growth and

development period.

Catabolic Reactions generate energyBreakdown of higher and complex

biological compounds to simple smaller molecules e.g., Oxidation of Glucose to Water and Carbon dioxide.Energy generation during catabolism of

nutrients (Glucose, Fats etc.).Dominant during chronic debilitating

disease (TB, Cancer etc.) and old age.

In a living cell both Anabolic and Catabolic reactions take place

simultaneously according to the requirements and demands

A particular setup of metabolic reactions in a cell is called the Metabolism of the cell.

Anabolic reactions are collectively called Anabolism.Catabolic reactions are collectively called Catabolism.

During life time balance ofAnabolism and Catabolism

shifts according to circumstancesGrowing age:

Anabolism is dominant.Adulthood:

Anabolism and Catabolismrun parallel and remains balanced.

Old age and prolonged diseases:Catabolism is dominant.

Energy is fundamentalrequirement of living systems

Chemical energyFor synthetic reactions.

Mechanical energyFor contraction of muscles.

Heat energyFor maintenance of temperature.

Energy can be produced by actual burning of organic substances in air

(Oxidation or Combustion).

Such energy is not suitable for living systems because:

Can not be controlled.Can not be stored.Requires drastic conditions.

In living system energy is generated by precise chemical methods

Energy produced by such chemical methods:

Is Precisely controlled and regulated according to requirements.

Can be stored for use at a proper time.

Do not require drastic conditions of Temperature, Pressure and pH.

Bioenergetics(Biochemical thermodynamics)

Study of the energy changes accompanying biochemical reactions. Study of generation, storage and

utilization of energy in living system.

Sources of Energy In Human cellsFree or useful energy is released

during catabolic reactions:Oxidation of energy-rich organic compounds (Cellular respiration):

GlucoseFats (Glycerol & Fatty acids).Amino acids.

Storage of energy in living systemFree or useful energy is released

during catabolic reactions.This energy is captured and stored as

high energy phosphate bonds.Compounds having high energy bonds

are called high-energy compounds.

Adenosine Triphosphate (ATP)is the most commonly usedEnergy Storing Molecule

Adenine|Ribose_______P

Adenosine Monophosphate

~ P ~ P

High Energy Phosphate Bonds

Capture of Energy as ATP

Adenine|Ribose_______P ~ P ~ PEnergy generated by oxidation of food

stuffs is utilized for the formation of High- energy phosphate bonds.

ADP is converted to ATP

Release of energy by ATP

Adenine|Ribose_______P ~ P ~ P

Hydrolysis of terminal Generates 7300 Calories.ATP is Converted to ADP

Release of energy by ATPPhosphate bond splits to release free

energy Approximately 7300 cal/mol. for each of two terminal phosphate groups.Adenosine diphosphate (ADP) and

Adenosine monophosphate (AMP) are formed respectively.Phosphate bond of AMP is a low-

energy bond.

Release of energy by ATP

Adenine|Ribose_______P ~ P + Pi

Energy generated is utilized for:1. Metabolic Reactions.2. Muscle Contraction.3. Heat.

Catabolism of Nutrients

CO2 + H2O

Energy

Adenine|Ribose__P

Adenosine Monophosphate

Adenine|Ribose__P __P

Adenosine Diphosphate

Adenine|Ribose__P __P __P

Adenosine Triphosphate

An Overview of Energy Storage

Organic molecules (Nutrients Such as Glucose & Fats) contain energy, stored

in their molecular structure

Breakdown (Catabolism) of these molecules generate the energy to

synthesize High energy Phosphate bonds (ATP)

Generation and utilization of energyin human tissues is an important

concern in medical science Medical problems due to energy imbalance:

StarvationUnavailability of Energy

ObesityExcess Storage of Energy

MarasmusEnergy imbalance due to Malnutrition

Hormonal DisordersDiabetes mellitus, Diseases of Thyroid

Cellular Respiration is theMain Source of Energy

The overall process of energy generation by breakdown of food is called Cellular Respiration.The process by which the chemical

energy of food molecules (Carbohydrates, Fats, and Proteins) is released and captured in the form of ATP.

ATP / ADP Cycle

Adenine |Ribose — P ~ ~ ATP

Adenine |Ribose — P ~ ADP

7300 cal/mol

ATP as energy currency-----------------------

ATP acts as currencyof energy, when energy

is gained from high-energymolecules, is stored in

this form and it pays it to low-energy molecules,

when required.