BIOL1102 Week 2(The cell)

• Cells are the fundamental unit of life
• Although cells differ substantially, they share common features
• Cell features


  • Plasma membrane
  • Cytosol
  • Chromosomes
  • Ribosomes

  
• Prokaryotic cells


  No nucleus, DNA located in nucleoid, no membrane bound organelles
• Prokaryotes consist solely of bacteria and archaea
• Eukaryotes consist of all living organisms other than eubacteria and archaea
• Prokaryotes are 1-10µm in size, eukaryotes are 10-100µm in size
• Eukaryotic cells


  True nucleus, membrane bound organelles
• Nucleus


  Contains most of the DNA, enclosed by nuclear envelope
• Ribosomes


  Carry out protein synthesis, suspended in cytosol, attached to ER or nuclear envelope, not membrane bound

  
• Endoplasmic Reticulum (ER)


  • Rough ER - synthesis of secretory proteins, membrane proteins and lipids
  • Smooth ER - synthesis of lipids, metabolism of carbohydrates, detox of the cell and storage of calcium ions

  
• Golgi Apparatus


  Modifies proteins, transport warehouse
• Lysosomes


  Contain hydrolytic enzymes to digest food, involved in phagocytosis and autophagy
• Vacuole


  Membrane bound, empty of cytoplasm
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• Mitochondria


  • Site of cellular respiration
  • Converts chemicals into energy
  • Mobile within cell
• Chloroplasts


  • Site of photosynthesis
  • Convert sunlight into energy
  • Mobile within cell
• Cytoskeleton


  Maintains cell shape and internal organization
• Animals and plants
• The cell membrane is integral to the function of all cells
• Fluid mosaic


  • Phospholipids
  • Cholesterol
  • Proteins
• Phospholipids


  • Glycerol
  • Two fatty acid tails
  • Phosphate-linked head group
• Biological membrane


  • Amphipathic (both hydrophilic and hydrophobic)
  • Hydrophilic (water loving)
  • Hydrophobic (water fearing)
• Membrane fluidity


  • Hydrophobic interactions
  • Lateral diffusion (1µm2 per second)
  • Flip-Flop (rare)

  
• The nucleus is the control center of the cell.