Molecular

• Molecular biology


  The study of all molecules in the cell
• Proteins and nucleotides


  • Have fundamental roles to sustain life
  • Proteins are the key components in everything related to life
• Living organisms


  Most are single cells, others are multicellular with groups of cells performing specialized functions and linked by communication systems<|>Whole organisms are generated by cell divisions from a single cell
• Organism


  Composed of organs which perform specific functions<|>(atom-molecule-macromolecule-organelle-cell-tissue-organ-organ system-organism)
• Cell


  The basic unit of life in all living organisms, containing molecules with fundamental functions for life
• Cells


  • Can be cultured in a lab where they will grow and reproduce
  • Highly complex and organized, with precise cellular activities
  • Possess a genetic program and means to use it
  • Capable of producing more of themselves through cell division
  • Acquire and utilize energy
  • Carry out a variety of chemical reactions
  • Engage in mechanical activities
  • Able to respond to stimuli
  • Capable of self-regulation
• Comparison of eukaryotic and prokaryotic cells

  • Eukaryotic cells are more complex structurally and functionally than prokaryotic cells
• Eukaryotic cell components


  • Nucleus: storage of DNA, RNA and ribosome synthesis
  • Endoplasmic reticulum: synthesis of lipids and proteins
  • Golgi apparatus: distribution and processing of proteins and lipids
  • Mitochondria: conversion of energy from food
  • Vesicles: transport, secretion, and digestion

  
• Both prokaryotic and eukaryotic cells have DNA containing chromosomes

  
• Eukaryotic chromosomes


  Contain single linear DNA molecules tightly associated with proteins to form chromatin
• Prokaryotic chromosomes


  Single, circular DNA molecules
• Cell composition


  Water (70% or more), inorganic ions, and carbon-containing organic molecules
• Elements in cells


  • Trace elements
  • Nitrogen (3.3%)
  • Hydrogen (9.5%)
  • Carbon (18.5%)
  • Oxygen (65%)
  • Calcium (1.5%)
  • Phosphorus (1%)
  • Potassium (0.4%)
  • Sulfur (0.3%)
  • Sodium (0.2%)
  • Chlorine (0.2%)
  • Magnesium (0.1%)
• Atoms


  Smallest unit of an element that can undergo chemical change<|>Joined by covalent bonds where electrons are shared
• Atomic structure


  Protons (positive charge) in nucleus<|>Neutrons (no charge) in nucleus<|>Electrons (negative charge) in orbits around nucleus
• Radioactive atoms


  Have too many neutrons in nucleus, making them unstable and giving off particles until stable
• Ions


  Atoms with extra or missing electrons, having a positive or negative charge, responsible for many chemical reactions
• Building blocks to larger units

  1. Sugars to polysaccharides

  2. Fatty acids to fats, lipids, membranes

  3. Amino acids to proteins

  4. Nucleotides to nucleic acids
• Components of a bacterial cell

  • 30% chemicals
  • 70% H2O
• Macromolecules in a bacterial cell

  • Ions, small molecules (4%)
  • Phospholipid (2%)
  • DNA (1%)
  • RNA (6%)
  • Proteins (15%)
  • Polysaccharides (2%)
• Basic macromolecules of life

  • DNA: Contains all the information needed by the cell
  • RNA: Transports information from DNA and plays crucial role in protein synthesis
  • Proteins: Many different functions, key constituents of organisms

  
• Ionic bonds


  Attraction between fully charged components
• Types of bonds


  • Covalent bonds (hydrogen bonds)
  • Double covalent bonds (oxygen bonds)
  • Multiple covalent bonds (methane bonds)
• Hydrogen bonds


  Occur between most polar molecules, important in determining structure and properties of water, weak bonds
• Functional groups


  Particular groupings of atoms that give organic molecules their physical properties, chemical reactivity, and solubility
• The science of genetics began with the work of Gregor Mendel


  1860s
• Genes


  Can exist in different forms called alleles<|>One allele from each parent, with dominant alleles determining characteristics
• Transforming factor


  Substance passed from dead bacteria to live bacteria, later identified as DNA
• Chargaff's rule


  Concentration of thymine = adenine, concentration of cytosine = guanine, total purines = total pyrimidines

  
• Blender experiment 1952


  1. Infection

  2. Blending

  3. Centrifugation
• DNA structure


  Double helix, containing genetic information to build cells and tissues, and transmit information to future generations

  
• DNA in different organisms

  • Animal: Linear, long length, in nucleus
  • Bacteria: Circular, medium length, in cytoplasm
  • Virus: Linear or circular, short length, in capsid
• DNA and RNA


  Polynucleotides with high molecular weight, composed of nucleotides with sugar, phosphate, and base

  
• Location of DNA


  • Nucleus
  • Cytoplasm
  • Capsid
• DNA in the nucleus

  • Linear
  • Long length
• DNA in the cytoplasm

  • Circular
  • Medium length
• DNA/RNA in the capsid

  • Linear or Circular
  • Short length
• Deoxyribonucleic acid (DNA)


  Long polymer chains of small compounds called nucleotides
• Chemists had learned the general structure of DNA and of a related compound, ribonucleic acid (RNA). They are the polynucleotides having high molecular weight.

  
• Both DNA and RNA are long polymers: chains of small compounds called nucleotides.