11.13 (dr. saleem) overview of metabolism & bioenergetics ii oidative phosphorylation & electron transport chainPresentation Transcript
We have indeed created man in the best shape (Holy Quran) Lecture # 2 Biochemistry Foundation Module November-2010
Growth and reproduction and all other vital process depend on Hundreds of planned chemical reactions called metabolic reactions
Energy is fundamental requirement of living systems
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 cells
Free or useful energy is released during catabolic reactions:
Oxidation of energy-rich organic compounds (Cellular respiration):
Fats (Glycerol & Fatty acids).
Storage of energy in living system
Free 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 used Energy Storing Molecule Adenine | Ribose_______P Adenosine Monophosphate ~ P ~ P High Energy Phosphate Bonds
Capture of Energy as ATP Adenine | Ribose_______P ~ P ~ P Energy 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 ATP
Phosphate 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.
An Overview of Energy Storage Adenine | Ribose__P Adenosine Monophosphate Adenine | Ribose__P __P Adenosine Diphosphate Adenine | Ribose__P __P __P Adenosine Triphosphate Catabolism of Nutrients CO2 + H2O Energy
ATP / ADP Cycle Adenine | Ribose — P ~ ~ ATP Adenine | Ribose — P ~ ADP 7300 cal/mol
ATP as energy currency
ATP acts as currency
of energy, when energy
is gained from high-energy
molecules, is stored in
this form and it pays it to
Organic molecules (Nutrients Such as Glucose & Fats) contain energy, stored in their molecular structure
Catabolism of these molecules generate the energy to synthesize High-energy Phosphate bonds (ATP)
Generation and utilization of energy in human tissues is an important concern in medical science
Medical problems due to energy imbalance:
Unavailability of Energy
Excess Storage of Energy
Energy imbalance due to Malnutrition
Diabetes mellitus, Diseases of Thyroid
Cellular Respiration is the Main 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.
Cellular respiration is a complex biochemical phenomena backed up by:
Feel the difference between breathing and respiration!
Merely inhalation of Oxygen and expulsion of carbon dioxide is not respiration.
Blood circulatory System.
To generate energy through Cellular respiration a cell must have:
Required amount of Oxygen.
Sufficient quantity of energy generating molecules.
Required enzymes in cytosol and Mitochondria.
Certain derivatives of vitamins such as Thiamin, Niacin and Riboflavin).
Role of Carbohydrates, Fats, and Proteins Cellular Respiration Carbohydrates Proteins Fats Glucose Amino acids Fatty acids Glycerol CO2 + H2O + ATP (Energy)
Breakdown (Catabolism) of molecules generate the energy to synthesize ATP
Direct At Substrate Level:
At the time of reaction ADP is converted to ATP.
Indirect Through Biological Oxidation:
Hydrogen atoms generated during reaction go through a complex process of biological oxidation.
Metabolic Processes Involved In Cell Respiration
Glycolysis ; occurs in cytosol.
Oxidation of Fatty acids and Krebs Citric acid Cycle occur in Matrix of Mitochondria.
Biological Oxidation occurs in Inner Membrane of Mitochondria.
Two types of Cellular Respiration
Final Oxidizing agent (Electron Acceptor) is Oxygen.
The most Important Metabolic Source of Energy in Living cells (Exceptions?)
Contributes approximately 90% of total energy generated in cell.
Net result is CO2, H2O and Energy (ATP & Heat)
Final Oxidizing agent (Electron Acceptor) is Other than Oxygen.
Important Source of Energy in cells Not Having Mitochondria (RBC).
Cells Deprived of Oxygen (Exerting Muscles & Ischeamic Tissues)
A number of NAD and FAD molecules are reduced by H + generated during Glycolysis, Oxidation of Fatty acids and Krebs Citric acid Cycle
In various reactions of Glycolysis, Citric acid cycle and Oxidation of Fatty acids Hydrogen atoms are removed from the substrate and accepted by co-enzyme NAD and FAD.
Biological oxidation in the mitochondria is the final and most important step of cellular respiration
Reduced NAD (NADH) and Reduced FAD (FADH) ultimately pass their Hydrogen to Oxygen to form water
During this complex process elctron of hydrogen atom is seprated and takes part in genertaion of energy in the form of ATP
Cellular Respiration Glycolysis, Oxidation of Fatty acids and catabolism of Amino acids Citric Acid Cycle NADH FADH2 Biological Oxidation ADP ATP
The Final Stage of Cellular Respiration called Biological Oxidation
The Oxidation of NADH 2 & FADH generates as high as 90% of total energy generated by complete setup of Cellular Respiration.
Biological mechanism for the synthesis of ATP, Takes place in Inner Mitochondrial Membrane.
Includes two integrated mechanisms
Respiratory Chain, extracts energy from electrons of Hydrogen.
Oxidative Phosphorylation, utilizes extracted energy for the formation of high-energy bond.