General Biology Lab

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Lab 5 - Cells

Fundamental Units of Life – CELLS!

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Fundamental Units of Life – CELLS!
CELLS ARE - 

• Living Compartments
•   Organisms can exist as a single cells - amebas
•   Cells vary in size and shape; each is basically a fluid filled bag in which various structures are housed
•   Internal structures are called organelles (little organs in latin)
•   Living Compartments
•   Intracellular = “inside of the cell”
•   Extracellular = “outside of the cell”
•   Organelles are small membrane bound structures that have specific functions within the cell

Prokaryotic vs. Eukaryotic

•   Prokaryotic = DO NOT have a membrane-bound nucleus or organelles
  • ​​bacteria
•   Eukaryotic = Have a membrane bound nucleus and membrane-bound organelles
  • ​​both plants and animal cells are eukaryotic

  

  Plant Cells vs. Animal Cells

 Property                                   Animal Cell                                                 Plant Cell
            Cell wall                                                           Present (formed of cellulose)                                                                Absent
                Shape                                                                  Round (irregular shape)                                                       Rectangular (fixed shape)
               Vacuole                                       One or more small vacuoles (much smaller than plant cells)    One, large central vacuole taking up 90% of cell volume.
            Centrioles                                                             Present in all animal cells                                           Only present in lower plant forms.
          Chloroplast                                              Animal cells don't have chloroplasts              Plant cells have chloroplasts because they make their own food.
              Plastids                                                                                Absent                                                                                           Present
   Plasma Membrane                                                    Only cell membrane                                                       Cell wall and a cell membrane
           Lysosomes                                                   Lysosomes occur in cytoplasm                                            Lysosomes usually not evident.
                   Cilia                                                                                  Present                                                                 Most plant cells do not contain cilia.



  Cell Structure

Cell Wall

• Composed of complex carbohydrate-cellulose
•   Humans are unable to digest cellulose because the appropriate enzymes to breakdown the beta-acetal linkages it has are lacking. 
• Support, rigidity, and protection
• Surrounds plasma membrane
•   PLANT CELLS ONLY!!
  

Plasma membrane (cell skin?)

•   Double lipid bilayer (2 layers)
• Composed of protein and phospholipids
• The membrane regulates the exchange of substances (nutrients/waste/signaling molecules) between the cell and its surrounding
•   Cell Structure
•   Cytoplasm (cell blood?)
•   liquid substance inside the plasma membrane and outside the nucleus
•   Where biochemical reactions occur and organelles are suspended
•   BOTH plant and animal cells
•   Cell Structure

  Flagella / Cilia (cell feet/arms?)

• Aid in locomotion
•   BOTH Plant and Animal cells can have these.
•   Cell Structure - Organelles
•   Nucleus (cell brain?)
• Contains genetic instructions (DNA)
• Controls cellular activities
•   BOTH plant and animal cells
•   Cell Structure - Organelles

  Mitochondria (cell engine?)

• Release of energy from sugars in the form of ATP through cellular respiration
•   BOTH plant and animal cells
•   Cell Structure - Organelles

  Chloroplasts

•   Acquire energy through light (absorb photons!) and convert into chemical energy by photosynthesis
•   Contain green photosynthetic pigments - chlorophyll.
•   PLANT Cells ONLY!!!
•   Cell Structure - Organelles

  Ribosomes

• Protein synthesis
•   BOTH Plant and Animal Cells
•   Cell Structure - Organelles

  Endoplasmic reticulum (cell circulatory system?)

• Transport of proteins and synthesis of lipids
•   BOTH Plant and Animal cells
•   Cell Structure - Organelles

  Golgi Bodies (cell post office)

• Modification, packaging and shipping of proteins, lipids and carbohydrates
•   BOTH Plant and Animal cells
•   Cell Structure - Organelles

  Central vacuoles (plant cell stomach?)

• Storage of water, wastes, and nutrients
• Influences cell size and shape – TURGOR PRESSURE
•   PLANT cells ONLY!!!
•   Cell Structure - Organelles

  Lysosomes – (cell digestive tract?)

• Contain enzymes for intracellular digestion of bacteria, cellular debris, and worn out cell parts
•   Animal Cells ONLY!!!

 Cytoskeleton

• protein filaments that give structure and create a scaffold for organelles.
•   Animal Cells ONLY!!!

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