LQB182 Week 1 Lecture Notes

Unit Introduction

  • Learning Objectives of the Unit

    • What are cells?
    • Cells are singular units that compose tissues and perform their functions.
    • What are cells made from?
    • Central dogma of biology: DNA (genes) → RNA (message) → Protein (structural and functional macromolecule)
    • Cell building blocks:
      • Carbohydrates
      • Amino acids
      • Lipids
      • Minerals, ions, water
    • Cells can break down and reconfigure these components.
    • Cell Parts, Structure, and Function
    • Organelles: the functioning parts of a cell, akin to organs in a body.

  • Key Concepts

    • Polymerisation
    • Structure relates to function
    • Behavior of biological molecules

  • Practicals

    • Prac 1: Health and safety, Microscopes (best practice, measuring)
    • Prac 2 (assessed - 4%): Using a pipette, DNA extraction.
    • Prac 3 (assessed - 7%): Mitosis, Mendelian genetics.
    • Prac 4 (assessed - 6%): Enzyme activity, Amylase action experiments.
    • Prac 5 (assessed - 6%): Calculating ATP production in cells.

Chemistry for Biologists (2a)

  • Learning Objectives

    1. Atoms and ions contain specific numbers of electrons, protons, and neutrons.
    2. Compounds are formed from 2 or more bonded atoms.
    3. Intramolecular Bonds:
    • Types include metallic, ionic, and covalent bonds.
    1. Valence electrons determine ion charge and bond types.
    2. Compound shape is based on the bond type and specific atom/ion configurations.
    3. Intermolecular Bonds:
    • Include London Dispersion Forces, Dipole-Dipole interactions, and Hydrogen Bonding.
    1. Water properties, concentration, and moles.
    2. Overview of organic molecules, polymers, and macromolecules.

  • Elements in the Human Body

    • Key Elements:
    • Oxygen (O): 65.0%
    • Carbon (C): 18.5%
    • Hydrogen (H): 9.5%
    • Nitrogen (N): 3.3%
    • Calcium (Ca): 1.5%
    • Phosphorus (P): 1.0%
    • Potassium (K): 0.4%
    • Sulfur (S): 0.3%
    • Sodium (Na): 0.2%
    • Chlorine (Cl): 0.2%
    • Magnesium (Mg): 0.1%
    • Trace Elements (
    • Boron (B), Chromium (Cr), Cobalt (Co), Copper (Cu), Fluorine (F), Iodine (I), Iron (Fe), Manganese (Mn), Molybdenum (Mo), Selenium (Se), Silicon (Si), Tin (Sn), Vanadium (V), Zinc (Zn).

Atoms and Elements

  • Atoms: Smallest units of matter resembling the unique properties of elements.
    • Protons (p+) and neutrons (n0) are located in the atomic nucleus.
    • Electrons (e-) exist in a cloud around the nucleus.
    • Key Definitions:
    • Atomic Number = Number of protons
    • Atomic mass = Protons + Neutrons (molecular weight).
  • Combining Atoms to Form Molecules:
    • Interaction involves electrons arranged in quantized "shells":
    • Valence shell determines chemical behavior and bonding.
    • Max electrons per shell:
    • Shell 1: 2 e-
    • Shell 2: 8 e-
    • Shell 3: 18 e-
    • Shell 4: 32 e-

Chemical Bonds

  • Ion Formation:
    • Atoms can gain or lose electrons.
    • Gaining electrons leads to negative charge (Anions); losing leads to positive charge (Cations).
  • Bond Types:
    • Ionic Bonds:
    • Formed by the attraction of oppositely charged ions (e.g., sodium and chlorine).
    • Covalent Bonds:
    • Electrons are shared between atoms.
    • Can form single, double, or triple bonds.
    • Weaker Bonds (Intermolecular):
    • Hydrogen bonds, Dipole-dipole interactions, London dispersion forces.

Water and Biological Interactions

  • Water:
    • Most important biological solvent.
    • Dipoles are formed from covalent bonds (H-O-H).
    • Hydrogen bonding allows water to create network structures with other polar molecules.

Concentration and Reactions

  • Concentration:
    • Measure of how much of something exists in a certain volume.
      • Mole (6.02 x 10²³): A very large number used for measuring levels of substances.
  • Water Self-Ionisation:
    • Water can dissociate into Hydronium and Hydroxide ions.
  • Energy and Reactions:
    • Energy is absorbed to form covalent bonds and released when bonds break.

Macromolecules

  • Types of Macromolecules:
    1. Carbohydrates: Monosaccharide (e.g., glucose) → Polysaccharide (e.g., starch).
    2. Proteins: Amino Acids → Polypeptides.
    3. Nucleic Acids: Nucleotides → DNA or RNA.
    4. Lipids: Fatty acids and glycerol, do not form true polymers.
  • Polymerisation: Formation of larger structures from smaller units via covalent bonds.