Biochemistry in Medicine and Nutrition

Lectures presented by Dr. Mohamed Kotb El-Sayed, Professor of Pharmaceutical Biochemistry & Molecular Biology.
Dr. Mohamed I. Kotb, Professor of Pharmaceutical Biochemistry and Molecular Biology, is also mentioned.

Students will become familiar with the definition and importance of biochemistry.
Biochemistry and Clinical Medicine.
Interaction of Nutrition, Metabolism, and Disease.
Major Structural Components of the Body.
Biological Membranes.
ATP as Energy Currency.
Metabolism.
Role of Oxygen in Metabolism.
Fed-Fasting Cycle and Metabolism.
Genome and Metabolism.
A summary.

Biochemistry is the study of chemical processes in living organisms.
It encompasses all areas of life sciences, from botany to medicine and genetics.
Pure biochemistry aims to understand how biological molecules (carbohydrates, lipids, and proteins) lead to processes within living cells and whole organisms.
Biochemistry is closely related to molecular biology, which studies the molecular mechanisms behind genetic information.
Biochemistry deals with the structures, functions, and interactions of biological macromolecules (proteins, nucleic acids, carbohydrates, and lipids).
These macromolecules form the structure of cells and carry out many life functions.
The chemistry of the cell also depends on smaller molecules and ions (water, metal ions, and amino acids).
The mechanisms cells use energy are known as metabolism.
The outcomes of biochemistry are applied in medicine and nutrition.
Biochemists investigate disease causes in medicine.
In nutrition, they study maintaining health and understanding nutritional deficiencies.
Biochemistry focuses on cellular components (proteins, carbohydrates, lipids, nucleic acids, and other biomolecules).

Biochemistry covers clinical applications of biotechnology and genomics.
It relates to how diet, exercise, and metabolic stress impact health and performance as organisms age.
Also related to cellular signaling and communication responses to internal and external stressors.

Biochemistry shows the interplay between nutrition, metabolism, and disease.
Humans consume food, water, and oxygen, which are used in oxidative metabolism for energy and body temperature maintenance.
Food intake significantly impacts health, malnutrition and obesity/diabetes are current public health issues globally.

Proteins are building blocks and catalysts for various functions: forming tissue structure, and catalyzing biochemical reactions.
Lipids (like cholesterol and phospholipids) are the backbone of biological membranes.
Carbohydrates and lipids are primary energy sources, stored as glycogen and triglycerides.
These molecules can be linked to form important structures involved in signaling and immunity.
Chemical variables (like pH, oxygen tension, and ionic concentration) help define the homeostatic environment for metabolism.
Even small changes in this environment can be harmful.
Blood acts as a transport medium in the exchange of gases, fuels, metabolites, and information between tissues.

Membranes are formed from phospholipid bilayers that are impermeable to polar molecules.
They partition metabolic pathways within cells.
Membranes have gated channels, transporters, and receptor proteins.
Receptors initiate intracellular signaling.
Membranes play a key role in transport and signal transduction, both within individual cells and between different cells.
Membrane potentials are critical for nerve signaling, muscle contraction, and nutrient transport.

Energy released from nutrients is stored in adenosine triphosphate (ATP).
ATP is the "common currency" for metabolism, allowing energy use for work, transport, and biosynthesis.
Energy capture in biological systems occurs through oxidative phosphorylation, taking place in the mitochondria.
Oxygen consumption, or respiration is an essential part of this process, generating a hydrogen ion gradient across the mitochondrial membrane, which then creates ATP.

Metabolism is a complex network of chemical reactions.
Carbohydrates and lipids are the main energy sources but nutritional needs also include amino acids, inorganic molecules (containing sodium, potassium, phosphate, and other atoms), and micronutrients (vitamins and trace elements).
Glucose undergoes glycolysis, an anaerobic pathway for energy production.
Glycolysis produces pyruvate initiating oxidative metabolism (Krebs cycle) in the mitochondria.

Glycolysis also generates metabolites for amino acid, protein, lipid, and nucleic acid synthesis.
Glucose is crucial for brain function; maintaining its concentration is vital for survival.
Glucose metabolism is linked to glycogen (its short-term storage form).
Glucose homeostasis is controlled by hormones, primarily insulin, regulating metabolic processes between cells and organs.

Oxygen is essential for energy production in aerobic metabolism, transforming pyruvate to acetyl-CoA, an intermediate in carbohydrate, lipid, and amino acid metabolism.
Acetyl-CoA enters the central metabolic cycle (TCA cycle) in mitochondria.
Acetyl-CoA is oxidized, reducing coenzymes (NAD+ and FAD), capturing energy during fuel oxidation.
Oxygen is essential for the final oxidative phosphorylation pathway, reducing oxygen and creating ATP.
Oxygen can also cause oxidative stress, leading to tissue damage.

Metabolism cycles between fasting and eating states.
Pathways like glycolysis and glycogen synthesis are active during feeding, storing excess metabolites.
During fasting, glycogenolysis and lipolysis reverse the process, degrading stores for energy production when nutrients are not available.
Depletion of glycogen triggers gluconeogenesis to provide a constant glucose supply.
Conditions like diabetes, obesity, and atherosclerosis result from impaired fuel metabolism and transport.

The genome controls the conservation and transfer of genetic information through gene expression and protein synthesis.
Protein synthesis is driven by information encoded in DNA, transcribed into RNA, and translated into peptides forming protein molecules.
Recombinant DNA technology has revolutionized clinical and industrial biotechnology.

A visual representation showing the interconnectedness of metabolic pathways.
Metabolic pathways involve the transformation of molecules for energy production and biosynthesis.