Introduction to Biochemistry-Md and BSN.pptx

Biochemistry

1. INTRODUCTION TO BIOCHEMISTRY 1

2. INTRODUCTION TO BASIC BIOCHEMISTRY Biochemistry can be defined as the science concerned with the chemical basis of life. BIO = LIFE (Greek) The cell is the structural unit of living systems. Thus, biochemistry can also be described as: The science concerned with the chemical constituents of living cells and with the reactions they undergo.

3. What is Biochemistr y ? Biochemistry is the application of chemistry to the study of biological processes at the cellular and molecular level. It emerged as a distinct discipline around the beginning of the 20th century when scientists combined chemistry, physiology and biology to investigate the chemistry of living systems by: Studying the structure and behavior of the complex molecules found in biological material. The ways these molecules interact to form cells, tissues and whole organism.

4. Cells Basic building blocks of life Smallest living unit of an organism Grow, reproduce, use energy, adapt, respond to their environment Many cannot be seen with the naked eye A cell may be an entire organism or it may be one of billions of cells that make up the organism Basis Types of Cells: Prokaryotic and eukaryotic

5. Biomolecules : The four main classes of molecules in biochemistry are: carbohydrates, lipids, proteins, and nucleic acids. Monomers are relatively small molecules that are linked together to create large macromolecules, which are known as P olymers .

6. 8

7. Biomolecule s Carbohydrates are made from monomers called monosaccharides. Examples of these monosaccharide include glucose (C 6 H 12 O 6 ), fructose (C 6 H 12 O 6 )

8. Sugars Carbohydrates most abundant organic molecule found in nature. • Initially synthesized in plants from a complex series of reactions involving photosynthesis. Basic unit is monosaccharaides. Monosaccharaides can form larger molecules e.g. glycogen, plant starch or cellulose. Functions Store energy in the form of starch (photosynthesis in plants) or glycogen (in animals and humans). Provide energy through metabolism pathways and cycles. Supply carbon for synthesis of other compounds. Form structural components in cells and tissues.

9. Lipids are usually made from one molecule of glycerol combined with other molecules. For example in triglycerides , the main group of bulk lipids, there is one molecule of glycerol and three fatty acids.

10. Fatty acids 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, streiods (cholestrol, sex hormones), fat soluble vitamins. Functions Storage of energy in the form of fat Membrane structures Insulation (thermal blanket) Synthesis of hormones

11. Proteins are very large molecules made from monomers called amino acids. There are 20 standard amino acids. When amino acids combine, they form a special bond called a peptide bond and become a polypeptide, or protein.

12. Amino Acids Building blocks of proteins. 20 commonly occurring. Contains amino group and carboxyl group R function g roup (side chains) determines the Also determines how the protein folds and its biological function. Individual amino acids in protein connected by peptide bond.

13. Nucleic acids are the molecules that make up DNA, (to store their genetic information). The most common nucleic acids are D eoxyribonucleic acid (DNA) and R ibonucleic acid (RNA).

14. 16

15. B iochemistry is essential to all life sciences Genetics :The biochemistry of the nucleic acids lies at the heart of genetics. Physiology : The study of body function, overlaps with biochemistry almost completely. Immunology employs numerous biochemical techniques.

16. Pharmacology and pharmacy rest on a sound knowledge of biochemistry and physiology; in particular, most drugs are metabolized by enzyme- catalyzed reactions. Toxicology : Poisons act on biochemical reactions or processes. Pathology (the study of disease) : Biochemical approaches are being used increasingly to study basic aspects of such as inflammation, cell injury, and cancer.

17. Relationship between biochemistry & medici ne The interrelationship of biochemistry and medicine is a wide, two- way street. Biochemical studies have illuminated many aspects of health and disease, and conversely, the study of various aspects of health and disease has opened up new areas of biochemistry.

18. 20

19. 21

20. 22

21. 23

22. 24

23. 25

24. A ll disease has a biochemical basis Most, if not all diseases are manifestations of abnormalities of molecules, chemical reactions, or biochemical processes. Biochemistry has become the foundation for understanding all biological processes. It has provided explanations for the causes of many diseases in humans, animals and plants.

25. Molecular Biology

26. Molecular biology is a field of biology that studies the molecular basis of biological activity. It involves the study of the structure, function, and interactions of biological macromolecules such as proteins and nucleic acids. It deals with the nature of biological phenomena at the molecular level through the study of DNA, RNA, and proteins involved in genetic and cell functions.

27. Nucleic acids Nucleic acids are large biomolecules essential to all known life forms. They are composed of nucleotides, which are the monomer components. Nucleotides have three components: a nitrogen-containing base, a five-carbon sugar, and a phosphate group. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA is the genetic material in all free-living organisms and most viruses, while RNA plays an important role in certain processes such as the making of proteins.

28. Nucleic acids carry information in cells and make up genetic material. They create, encode, and store information in every living cell of every life-form on Earth. They also send and express that information inside and outside the cell nucleus. Nucleic acids are responsible for the storage of genetic information and protein synthesis. DNA and RNA are made up of monomers called nucleotides, which are linked together by dehydration synthesis or polymerization.

29. Chromosomes chromosomes are essential structures that carry genetic information from cell to cell. They are made up of DNA and proteins and are located inside the nucleus of animal and plant cells. Chromosomes are not visible in the cell’s nucleus when the cell is not dividing, but they become visible under a microscope during cell division.

30. Humans have 23 pairs of chromosomes, including 22 pairs of autosomes and one pair of sex chromosomes. Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, and the location of the centromere on each chromosome gives the chromosome its characteristic shape.

31. Genes G enes are the basic physical and functional unit of heredity. They are made up of DNA and are located on chromosomes. Genes contain the information needed to specify physical and biological traits. Some genes act as instructions to make molecules called proteins, while others do not code for proteins. Humans have approximately 20,000 to 25,000 genes, and every person has two copies of each gene, one inherited from each parent. Most genes are the same in all people, but a small number of genes are slightly different between people, which are called alleles. 

32. Cell membrane and Signal transduction

33. The biochemistry of the cell membrane is a complex and fascinating subject that involves the study of the structure, function, and composition of the membrane. It is a critical component of all cells, providing a barrier between the interior and exterior of the cell, controlling the flow of molecules in and out of the cell, and facilitating communication between cells. The cell membrane is composed of a variety of molecules, including lipids, proteins, and carbohydrates, all of which play important roles in maintaining the integrity and function of the membrane. Understanding the biochemistry of the cell membrane is essential for understanding the fundamental processes of life.

34. The cell membrane, also known as the plasma membrane or cytoplasmic membrane, is a thin layer that forms the outer boundary of a living cell and separates and protects the interior of the cell from the outside environment It is composed primarily of fatty-acid-based lipids and proteins The membrane lipids are principally of two types, phospholipids and sterols, which dissolve readily in organic solvents and have a region that is attracted to and soluble in water The proteins are inserted into the lipid bilayer and carry out many specialized functions, such as regulating the transport of materials entering and exiting the cell, cell adhesion, ion conductivity, and cell signaling

35. The cell membrane is selectively permeable to ions and organic molecules, allowing some dissolved substances to pass while blocking others The fluid mosaic model is the primary archetype for the cell membrane, which describes the membrane as a fluid mosaic in which proteins are inserted into a lipid bilayer The cell membrane is involved in a variety of cellular processes and serves as the attachment surface for several extracellular structures, including the cell wall and the carbohydrate layer called the glycocalyx, as well as the intracellular network of protein fibers called the cytoskeleton

36. Lipid Bilayer: The primary structure is a double layer of phospholipids, with hydrophobic tails oriented inward and hydrophilic heads facing outward, creating a stable barrier. Proteins: Proteins are embedded in the lipid bilayer, some spanning the entire membrane (integral proteins) and others attached to the surface (peripheral proteins). These proteins contribute to the functionality and selectivity of the membrane. Cholesterol: Cholesterol molecules are interspersed among the phospholipids, adding stability to the membrane and modulating its fluidity. Carbohydrates: Carbohydrates are often found attached to proteins (glycoproteins) or lipids (glycolipids) on the extracellular surface, playing a role in cell recognition and signaling.

37. Phospholipids Formation of the Lipid Bilayer: Phospholipids are the primary building blocks of the lipid bilayer, the basic structural framework of cell membranes. The hydrophobic tails of phospholipids align together, creating a barrier that separates the internal and external environments of the cell. Selective Permeability: The amphipathic nature of phospholipids (hydrophilic head and hydrophobic tail) contributes to the selective permeability of the membrane. This allows the membrane to regulate the passage of substances, controlling what enters and exits the cell. Cell Signaling: Phospholipids, especially those containing signaling molecules like phosphatidylinositol, play a role in cell signaling pathways. Protein Anchoring: Proteins are often embedded in the lipid bilayer, and phospholipids provide an anchor for these membrane proteins. Some proteins are partially or entirely embedded in the hydrophobic region of the membrane, contributing to the membrane's structural integrity and facilitating various cellular functions.

38. Ion Channel proteins Ion Selectivity: Ion channels are selective about the types of ions they allow to pass through. Different channels are specific to certain ions such as sodium (Na+), potassium (K+), calcium (Ca2+), or chloride (Cl-). This selectivity is crucial for maintaining the proper ion concentrations inside and outside the cell. Membrane Potential Regulation: Ion channels contribute to the establishment and regulation of the cell's membrane potential. By allowing the selective movement of ions across the membrane, ion channels influence the electrical charge of the cell. Nerve Signal Transmission: In neurons, ion channels play a fundamental role in the generation and propagation of action potentials. Voltage-gated sodium and potassium channels, for example, are involved in the rapid changes in membrane potential essential for nerve signal transmission.

39. Muscle Contraction: Ion channels are involved in the regulation of muscle contraction. Calcium channels, both voltage-gated and ligand-gated, play a crucial role in initiating muscle contraction by allowing the influx of calcium ions into muscle cells. Cellular Excitability: Ion channels contribute to the excitability of cells, allowing them to respond to stimuli. Changes in membrane potential, facilitated by the opening and closing of ion channels, lead to cellular responses such as muscle contraction or the release of neurotransmitters.