EXAM - UNIT 1

• Cell Theory 


  1.All living things are made up of cells

  2.Cells are the smallest and most basic unit of biology

  3.All cells come from pre-existing cells
• Prokaryotes 


  Group of single-celled organisums with no nucleus or membrane bound organelles and a circular loop of DNA. Include bacteria and archea.
• Eukaryotes 


  Group of single or multi-celled organisums with a nucleous and membrane bound organelles and linear strands of DNA. Include animal, plant, fungi and protists.
• Differences between Animal and Plant Cells

  1.Cell wall present in plant cells but not in animal cells

  2.Chloroplasts present in plant cells but not animal cells

  3.Vacuoles in animal cells are small and can be multiple or none, whereas plant cells have one large vacuole
• Organnelles - Define


  A cellular structure that performs specific functions
• Cytosol 


  Fluid that surrounds organelles
• Cytoplasm 


  Cytosol and organelles in plasma membrane (aside from nucleus)
• Cellular Respiration 


  Process that converts glucose into ATP
• Surface Area to Volume Ratio (SA:V)

  A comparison of the amount of surface area per unit of volume.

  • A greater surface area and smaller volume, or high SA:V can help a cell exchange materials efficiency with environment.
• SA:V - Benefitsof small cells


  -Exchange of materials with extracellular environment can occur efficiently due to high SA:V

  -Distances to travel within the cell are smaller, so intracellular transport of molecules is faster
• SA:V - Influence


  In biology influences temperature regulation, and high SA:V lead to more effective transport into and out of cell.
• Plasma Membrane


  A phospholipid Bilayer embedded with proteins carbohydrates, and cholesterol. Each of these molecules fulfil specific function in the membrane.
• Phospholipids


  Made up of Phosphate head and two fatty acid tails
• Phosphate Head 


  Polar, Hydrophilic, negatively charged, water loving
• Two Fatty Acid Tails

  Non polar, hydrophobic, uncharged, repel water
• PLASMA MEMBRANE - PROTIENS

  Structure: Intergral proteins, transmembrane Proteins, Peripheral Proteins.

  Functions: Transport, Communication, Catalysis, Adhesion.
• Intergral Proteins


  Permanent Part of the membrane
• Transmembrane Proteins


  Integral proteins that span the entire bilayer
• Peripheral Proteins


  Temporally attached to the plasma membrane
• CARBOHYDRATES


  Structure: usually in chains that extend outside the cell rooted in membrane lipids.

  Function: Aid Cell to Cell Communication, signalling and recognition.
• CHOLESTEROL 


  Structure: Lipid steroid embeds itself between fatty acid tails in phospholipid bilayer.

  Functions: Regulate fluidity of the membrane.
• Fluid Mosaic Model


  Theory of how plasma membrane is structured, phospholipids continually move side to side in membrane, molecules move fluidly throughout bilayer has flow.
• Passive Transport 


  Movement of molecules through semipermeable membrane and down concentration gradient without use of energy.
• Active Transport 


  Movement of molecules across semipermeable membrane that require energy.
• Diffusion


  The passive movement of non polar/hydrophobic small molecules from areas of high concentration to areas of low concentration (down the concentration gradient)

  EG: Oxygen, Carbon
• Facilitated Diffusion


  Passive transport where molecules move through phospholipid bilayer with the aid of a membrane protein such protein channel or carrier protein. (Down concentration gradient)

  EG: Ions, Glucose.
• Osmosis


  Passive Transport of water through semi-permable membrane from region of low solute (high solvent) to region of high solute (low solvent). (Hypertonic to Hypotonic solution).
• Concentration Gradient


  The difference in solute concentration between to different areas.
• Hypertonic


  Solution with higher solute concentration compared to another solution
• Hypotonic


  Solution with lower solute concentration compared to another solution
• Isotonic 


  Solution with same amount of solute concentration compared to another solution.
• Turid 


  Describes plant cells that are swollen and firm from water uptake.
• Solute 


  A substance dissolved in the solvent
• Solvent 


  A liquid in which the solute is dissolved, forming a solution

  (eg water (solvent) + salt (Solute) = solution)
• Active Transport (Protein Meditated Active Transport)


  Active transport of molecules against their concentration gradient across the membrane, using membrane proteins.

  1. BINDING: molecule binds to specific protein pump
  2. CONFORMATIONAL CHANGE: reaction of ATP - ADP releases energy which leads to conformational change in protein pumps.
  3. RELEASE: Target Molecule released to other side of membrane
• Bulk Transport 


  Active transport that uses vesicles to move large molecules or groups of molecules into or out of the cell, across plasma membrane.

  TWO FORMS: Exocytosis, Endocytosis.
• Bulk Transport - Exocytosis

  Bulk transport of large molecules out of the cell.

  1. Vesicular Transport: vesicles (containing secretory products) transported to plasma membrane
  2. Fusion: Membrane of vesicles and cells fuse
  3. Release: Secretory products released from vesicle and out of cell.
• Vesicle


  A small membrane-bound sac that transports or stores substances within a cell.
• Secretory products 


  The substances inside vesicle that are being transported out of cell
• Proteins - Extocytosis


  -Made at ribosomes.

  -located on surface of rough endoplasmic reticulum,

  -sorted, packaged and modified at the Golgi apparatus

  -transported be vesicles to plasma membrane for extocytosis.