BIOCHEM

• Cell organelles are important for understanding biochemical reactions associated with life
• Nucleus:

  • Cell's command center
  • Contains genes (DNA and RNA)
  • Enveloped by ER
• Endoplasmic Reticulum (ER):

  • System of tubules and flattened sacs
  • Rough ER associated with ribosomes, size corresponds to protein quantity
  • Smooth ER synthesizes proteins for cell's own use
• Mitochondria:

  • Largest cytoplasmic organelles, cell's power plants
  • Smooth outer membrane and folded inner membrane (cristae)
  • Synthesizes and stores energy in the form of ATP
  • Self-regulating organelle, synthesizes own proteins, self-duplicating
  • Controls concentration of water, calcium, and other ions, breakdown and recycling of sugars, fatty acids, and amino acids
• Cell Membrane:

  • Cell's delicate but tough "guardian"
  • Composed of lipids, proteins, and oligosaccharides
  • Regulates translocation of materials
• Golgi Apparatus:

  • Packagers of cell's proteins
  • Concentrates and wraps certain enzymes into separate organelles
• Microtubules and Microfilament:

  • Not membrane-bound
  • For transport of materials, cell movement, and support
• Ribosomes:

  • Cell's protein factories
  • Made up of two unequal subunits, each containing RNA
  • Sites for protein synthesis
• Lysosome:

  • Scavengers of the cell
  • Principal site of intracellular digestion
• Cell macromolecules associated with organelles:

  • Nucleus: nucleic acids, proteins, lipids
  • ER: lipids, proteins
  • Ribosomes: RNA, proteins
  • Mitochondria: proteins, lipids, CHO, nucleic acid
  • Golgi Apparatus: proteins, lipids, CHO
  • Lysosome: proteins
  • Cell membrane: lipids, proteins, CHO protein
• Water and pH:

  • Water is essential for plant and animal growth
  • Major component of the cell, modifies structures of biomolecules
  • General properties of water:
  • Colorless, odorless, tasteless
  • Higher boiling point and osmotic pressure
  • High specific heat
  • High latent heat of vaporization
  • High surface tension
  • Capacity to dissipate heat to its environment
• Cell Inorganic System:

  • Cell is a combination of true and colloidal solution
  • Colloidal properties of the cell:
  • Filterability
  • Negligible Osmotic Pressure
  • Tyndall Phenomenon
  • Brownian Movement
  • Electrical Charges
• Physiological Buffer System:

  • Buffers resist pH changes
  • Weak acids and their conjugate bases exhibit buffering
  • In humans, bicarbonate system and phosphoric acid are important intra and extracellular buffering systems
• Biological Importance of Water:

  • Universal solvent
  • Electron dipole
  • Altered by solutes
  • Tendency to dissociate
• Inorganic ions:

  • Vital for enzyme functioning and maintenance of functional conformation of biomolecules