Basic Concepts of Biochemistry

Basic Concepts of Biochemistry

Intended Learning Outcomes (ILOs)
  • Upon completion, students should be able to:
    • ILO1: Explain the structures and function of basic biomolecules.
    • ILO2: Describe the action of biological buffers.
    • ILO3: Explain the structure and functions of biological membranes.
    • ILO4: Describe cellular transport mechanisms.
    • ILO5: Explain the general characteristics of enzymes including kinetics.
    • ILO6: Explain the functions and mechanisms of selected hormones.
Introduction to Biomolecules (10 h)
1. Carbohydrates
  • Monosaccharides: Basic units such as glucose, fructose, galactose.
    • Isomerism affects molecular structure and properties.
    • Optical rotation is related to the arrangement of atoms.
  • Disaccharides: Formed from two monosaccharides; includes sucrose, maltose.
    • Formation involves glycosidic bonds.
  • Polysaccharides: Larger molecules such as starch, glycogen, cellulose, and chitin.
    • Biological importance includes energy storage and structural functions.
  • Testing and identification of carbohydrates include assays and their implications for functions in the body.
    • Glycoproteins and glycosaminoglycans emerge as significant molecules in cellular functions.
2. Lipids
  • Fatty Acids: Can be saturated or unsaturated, with characteristics defined by their carbon chains and presence of double bonds (nomenclature).
    • Essential fatty acids are vital for human health.
  • Triacylglycerols & Phospholipids: Key storage and structural components in biological membranes.
    • Amphipathic properties of phospholipids allow for membrane formation.
3. Amino Acids & Proteins
  • Fundamental building blocks of proteins, classified by side chains:
    • Charged Side Chains: (e.g., Lysine (Lys), Histidine (His), Arginine (Arg)).
    • Polar Uncharged Side Chains: (e.g., Serine (Ser), Glutamine (Gln), Asparagine (Asn)).
    • Hydrophobic Side Chains: (e.g., Alanine (Ala), Methionine (Met), Phenylalanine (Phe)).
  • Biological Importance: Proteins provide energy, serve as structural units, and participate in various biological processes such as transportation and signaling.
  • Peptide Bonds: Formed between amino acids, creating chains that fold into functional proteins.
Structure and Functions of Nucleic Acids (6 h)
  • Nucleosides & Nucleotides: Building blocks of DNA and RNA.
  • DNA Replication: Mechanism by which genetic information is copied.
  • Transcription and Translation: Processes of gene expression in both prokaryotes and eukaryotes.
Proteins: Structure and Organization
  • Primary Structure: Linear sequence of amino acids.
    • Determined by the gene sequence.
  • Secondary Structure: Includes alpha helices and beta-pleated sheets formed by hydrogen bonding between backbone atoms.
  • Tertiary Structure: The 3D shape formed by interactions among side chains, influencing protein functionality.
  • Quaternary Structure: Assembly of multiple polypeptide chains into a single complex.
Classification of Proteins
  • Simple Proteins: Composed solely of amino acids.
  • Conjugated Proteins: Contain additional non-protein components (e.g., lipids, carbohydrates).
  • Derived Proteins: Modifications of simple or conjugated proteins (e.g., denatured proteins).
Denaturation of Proteins
  • What is Denaturation?: Disruption of the secondary, tertiary, and quaternary structure, leaving the primary structure intact.
  • Methods Causing Denaturation:
    • Heat, acids, organic solvents, heavy metals, chaotropic agents, mechanical agitation.
  • Reversible Denaturation: Some proteins can refold back to their original structure under certain conditions, known as renaturation.
Key Functions of Proteins
  • Enzymatic Activity: Catalyze biochemical reactions.
  • Structural Roles: Provide support (e.g., collagen in connective tissues).
  • Transport: Move materials across cell membranes.
  • Signaling: Respond to external stimuli.
Tests for Proteins
  • Biuret Test: Violet coloration occurs when proteins react with copper sulfate in a sodium hydroxide solution, indicating peptide bonds.
  • Ninhydrin Test: Produces blue/violet coloration upon reacting with amino acids, useful for quantifying protein concentrations.
Important Definitions
  • Isoelectric Point (pI): The pH at which an amino acid is neutral and exists as a zwitterion (no overall charge).
  • Zwitterion: A dipolar ion that is neutral overall, significant in amino acid behavior in solutions.