General Biochemistry CHY 2026 Unit 1 PDF

CHY 2026: General Biochemistry Unit 1: Introduction to Biochemistry  Biochemistry  Biochemistry is the science concerned with the chemical nature or chemical behaviour of living matter – Metabolic reactions E.g. digestion, excretion, respiration etc. – Analysis of b...

CHY 2026: General Biochemistry Unit 1: Introduction to Biochemistry  Biochemistry  Biochemistry is the science concerned with the chemical nature or chemical behaviour of living matter – Metabolic reactions E.g. digestion, excretion, respiration etc. – Analysis of biomolecules – Characterization of cell components Biological phenomena are analyzed in terms of Chemistry  The Term was first introduced by Carl Neuberg (German Chemist) in 1903…early writing date back to 1500s Branches of Biochemistry Qualitative and quantitative Descriptive characterization of cell components Biochemistry Mechanism of action Dynamic involving these cell components Newer Disciplines  Enzymology  Endocrinology  Clinical Biochemistry  Molecular Biology  Biotechnology  Pharmacological Biochemistry  Nutrition  Fermentation Technology  Etc. http://biochem.otago.ac.nz/assets/images/SiteContentPhotos/BiochemistryCareerslg.jpg  Break out Discussion  Discuss the importance of Biochemistry in your course of study. Importance of Biochemistry 1. Understanding the cause of diseases 2. Composition of living cells and molecules present 3. Location of biomolecules in the cell and structure of the cells 4. Function of biomolecules and relationship between structure and function 5. Source of biochemicals in cells (a) Nutrients and (b) Cellular biosynthesis 6. Relationship between function of biomolecules, biosynthesis and biodegradation of cells 7. Maintaining the concentration of cellular molecules in pathways and metabolic reactions Chemical Composition of Humans  Biological Importance of Water  Water - molecular compound H2O  It is essential for life  It is the most abundant substance on earth  Water account for ≥ 70% weight of most organism  An obese individual, the water constitutes a lower % i.e. 45-60%  Body temperature is maintained because water is expelled from the skin and lungs. loss of 10% of water – serious; loss of 20% - fatal Source: http://water.usgs.gov/edu/images/property-you.png  Water balance- the equilibrium between water intake and output  Metabolic water is available through the oxidation of food Oxidation of 100g Total mass of water macromolecules produced (g) Fat 107 Carbohydrate 55 Protein 41  If output> intake then dehydration occurs. This is serious in infants as their body pool of water is small and can readily be depleted  If water accumulates in tissues, then edema occurs…often seen in children with Kwashiorkor (sugar babies)  Values in litres Source: Jain, J. L., Jain, S. and Jain, N. (2006) Fundamentals of Biochemistry. (6th edition). S. Chad and Company Limited ©1979.  Overview of Chemical Composition of the Body  Carbon compounds are very versatile and can polymerize into large complex structures called macromolecules  Macromolecules are usually in the form of polymers  Polymers – joining together of smaller organic molecules (monomers) via condensation  Macromolecules have properties that are different from their constituent monomers  E.g. Glucose (carbohydrate monomer) is more soluble and sweeter than starch (carbohydrate polymer) Biological Macromolecules  The four major organic macromolecules are  Carbohydrates  Proteins  Lipids  Nucleic Acids Macromolecules Monomers Carbohydrates monosaccharides Proteins amino acids Lipids fatty acids and glycerols Nucleic acids nucleotides Organic Building Block Some Major Functions Examples Compound Carbohydrate: Monosaccharide ------------------ Energy storage; physical Glucose, fructose, structure galactose Disaccharide Monosaccharides Energy storage; physical Lactose, maltose, structure fructose Polysaccharide Monosaccharides Energy storage; physical Starch, cellulose, chitin, structure inulin, pectin Protein Amino acids Enzymes; toxins; physical Antibodies; viral structures surfaces, flagella; pili Lipid: Energy storage; thermal Fat, oil Triglyceride Fatty acids and glycerol insulation; shock absorption Phospholipids Fatty acids, glycerol, Foundation for cell Plasma membrane phosphate, and an R group membranes Steroids Four ringed structures Membrane stability Cholesterol Nucleic Acid Ribonucleotides; Inheritance; instructions for DNA, RNA deoxyribonucleotides protein synthesis  Carbohydrates  Referred to as sugars (saccharides)  The molecule is comprised of carbon (C), hydrogen (H) and oxygen (O)  Plants (30%) contain a significantly higher percentage of carbohydrate than animals (1%)  There are an important source of energy ◦ Brain can only use glucose for energy  They are a source of C for metabolic reactions  They form part of the structural framework for RNA and DNA causing flexibility of the rings and allowing for storage and expression of these genetic molecules  They help in maintaining the structure of cell wall of bacteria and plants  Carbohydrates  They are linked to proteins (glycoprotein) and lipids (glycolipid) which helps in cell to cell recognition, e.g. The sperm cell is able to search find and bind to an egg for fertilization to take place  Fibres – Increase bowel movement  Proteins  They are the most abundant intracellular macromolecule – most of the protein mass is found in the skeletal muscle  The molecule is comprised of the elements carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and small quantities of sulphur (S) – CHONs  Proteins found in animal: 0.5 -2.0% sulphur except for insulin which contains 3.4%  They are biological catalysts – enzymes  They act as carrier molecules transporting small molecules and ions e.g. haemoglobin (protein) transports oxygen in the erythrocytes  They are responsible for the high tensile strength of the skin and bone  They are responsible for immunoregulation  Receptor proteins help in the transmission of nerve impulses  They are a major component of muscle  Lipids  They are a heterogeneous group of compounds which includes fats, oils and waxes  They have high energy value and are an important constituent of the diet  The molecule in comprised of the elements carbon (C), hydrogen (H), and oxygen (O)  They are insoluble in water and are thus hydrophobic  They act as energy stores  They are stored under the skin and help to keep the body warm  They are the structural components of cells forming membranes  They are used as hormones which are important in the regulation of metabolic processes  Nucleic Acids  They are found in the nucleus and cytoplasm of the cell  They are made up of the elements, carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and phosphorus (P)  There exists two kinds Ribonucleic acid (RNA) Deoxyribonucleic acid (DNA)  They are found in animals, plants and viruses. However unlike plants and animals, viruses have either DNA or RNA…Do you know which nucleic acid is found in the human immunodeficiency virus (HIV)? Nucleic Acids  Nucleic acids are important They contain genetic information They transfer genetic information They are implicated in protein synthesis They form co-enzymes needed for metabolic reactions Functional Groups  Functional Group – group of atoms found within a molecule and have similar chemical properties when found in different molecules  Covalent and Non Covalent Interactions  Forces of attraction between individual distinct molecules are called intermolecular forces  The strength of the molecular forces between the molecules or atoms that make up a substance determines its state  Strong intermolecular forces tend to result in liquids and solids with high melting and boiling points  Weak intermolecular forces tend to result in gases with low melting and boiling points  Non Covalent Interactions  Non covalent interactions that are responsible for the 3-dimensional configuration that the biological polymers adopt  These interactions also play a very important role in the flexibility of the macromolecules, their interactions with each other and with other molecules in the cell  Non-covalent interactions can be classified as: 1. Hydrogen bonds 2. Ionic interactions 3. Van der waals interactions 4. Hydrophobic interactions  Hydrogen Bonding  These are intermolecular forces that are found in covalent compounds containing hydrogen  The interaction usually occurs between hydrogen present in the molecule and other small electronegative elements such as N, O and F  The small size of the electronegative atom allows for strong attraction between hydrogen and these elements  Hydrogen Bonding  H bonding should not be confused with chemical bonds as chemical bonds are much stronger than H bonds…H bond in liquid water have a bond energy 20 kJmol-1 compared to 460 kJmol-1 for the O-H covalent bond.  However, H bonding is the strongest of the intermolecular forces  Substances composed of molecules that form hydrogen bonds have higher MP and BP than substances that are composed of molecules that do not form H bonds Ionic Interactions  Other names- ionic bond, salt linkage, salt bridge, ion pair  Ionic interactions are attractions between oppositely charged ions  The attraction is strongest in a vacuum and weakest in a medium such as water Hydrophobic Interaction  Hydrophobic molecules are insoluble in water  The force that causes hydrophobic molecules or non polar portions of molecules to aggregate together rather than to dissolve in water is called the hydrophobic interactions  A non polar molecule cannot form hydrogen bonds with water molecules, so it distorts the usual water structure, forcing the water into a rigid cage of hydrogen-bonded molecules around it  Water molecules are normally in constant motion, and the formation of such cages restricts the motion of a number of water molecules; the effect is to increase the structural organization of water. This situation is energetically unfavorable because it decreases the randomness (entropy) of the population of water molecules  van der Waals Interactions  This type of interaction is caused by fluctuations in the electron distribution within molecules or atoms  There are two types of van derWaals Forces  London Dispersion Forces (weaker)  Dipole Dipole Forces (stronger)  London Dispersion Forces  Since all atoms and molecules have electrons then they have dispersion forces  Electrons are constantly moving. Therefore at any one instance there comes a point where the arrangement of electrons are asymmetrical  As a result a temporary dipole is created  The temporary dipole cause the atom to be attracted to other neighbouring atoms, inducing a temporary dipole in neighbouring atoms (Induce Dipole)  Larger and heavier atoms and molecules exhibit stronger dispersion forces than smaller and lighter ones  In a larger atom or molecule, the valence electrons are, on average, farther from the nuclei than in a smaller atom or molecule. They are less tightly held and can more easily form temporary dipoles  In addition the higher the melting point and/or boiling point in a molecule the stronger the dispersion forces Dipole-Dipole Forces  They are electrostatic interaction between permanent dipoles  This type of force exist in molecules that are polar  Polar molecules have a permanent dipole that interact with the permanent dipole of neighbouring molecules  The positive end of a permanent dipole is attracted to the negative end of another  The attraction is referred to as dipole-dipole forces  Because of this attraction, polar substances are able to dissolve in each other and polar liquids are miscible e.g. salt and water or ethanol and water  Also polar substances do not dissolve in nonpolar substances and polar and non polar liquids are immiscible e.g. oil and water Covalent Interaction  Disulphide Bonds, Disulphide linkages is a covalent bond derived from two thiol groups  The process occurs via chemical oxidation