Cellular Structure

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Cellular Structure
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Nucleus

• The control center of the cell (metabolism,
  protein synthesis)

3
Nucleus FYI

• Most cells contain only one nuclei
• Skeletal muscle many
• Mature RBCs none

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Nucleolus

• Dense region that contains DNA/RNA
• Synthesizes RNA and ribosomes

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Cytoplasm

• The watery fluid which contains the materials
  which enter the cell.
• Dissolves things, supports cell structure.

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Cytoplasm

• Three parts
• 1. Cytosol (liquid)
• 2. Organelles (little organs)
• 3. Inclusions (insoluble particles)

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Organelles

• Intracellular structure that performs a specific
  function or group of functions. (cellular
  respiration, releasing energy)

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Mitochondria

• The powerhouse of the cell.
• They create food to obtain energy for cell
  activities.
• Produces 95 of ATP

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Mitochondria

• of mitochondria energy level needed

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Matrix
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Cristae

• Lots of folds in mitochondria

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• The cristae greatly increase the inner membrane's
  surface area. It is on these cristae that food
  (sugar) is combined with oxygen to produce ATP -
  the primary energy source for the cell.

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Ribosomes

• Makes proteins in the cell. Protein factories-
  aka. protein synthesis
• Contains RNA

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Ribosomes

• Free-floating
• Proteins are made and enter in the cytosol

• Fixed
• Proteins enter ER where they are modified and
  packaged for export.

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Endoplasmic Reticulum (ER)

1. Synthesis
2. Storage
3. Transport

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Synthesis

• ER makes
• Carbohydrates
• Lipids

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Storage

• Storage of molecules that are absorbed from the
  cytosol.

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Transport

• Network of membranes. (Travel anywhere)

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Smooth (SER)

• Lack ribosomes (smooth)
• Focus on making carbohydrates and lipids

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Rough (RER)

• Contain ribosomes (hence rough)
• Focus on making proteins

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Golgi Apparatus

• Package proteins for storage and secretion from
  the cell.
• Exocytosis, package particles (forms lysosomes)

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Golgi Apparatus

• Page 55 of text.
• Example of exocytosis and membrane reconstruction.

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Lysosomes

• Digest worn out or unneeded cells and cell parts.
  

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Lysosomes

• Packages of digestive enzymes.
• Fight pathogens
• Why?????

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Specialized Structures
                              

• Organelles that are not common to all cells,
  therefore they are not necessary for the cell to
  operate.

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Microtubules

• Hollow tubes that give support and strength

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Centrosome

• The centrosome, also called the "microtubule
  organizing center", is an area in the cell where
  microtubles are produced.

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Cilia

• Hair-like microtubules attached to the plasma
  membrane that often help in movement

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Flagella

• A tail like structure used for movement

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Microvilli

• Extension/folding of membrane to help increase
  surface area.
• Found in kidney and intestinal cells.

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• http//www.stolaf.edu/people/giannini/flashanimat/
  cellstructures/endomembrane20protein20synthesis.
  swf
• http//www.wisc-online.com/objects/index_tj.asp?ob
  jIDAP11403

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S
M
T
U
K
N
P
Q
O
L
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AKA cell membrane
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COLOR CODE (Page 52 new)

• Glycoproteins (Globular) G
• Channel H
• Phospholipids Heads A
• Fatty acid tails S
• Carbohydrate (sugar)

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1. Hydrophobic

• Dislike Water
• Two fatty acid tails

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2. Hydrophilic

• Likes Water
• Non-lipid head

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• http//www.stolaf.edu/people/giannini/flashanimat/
  lipids/membrane20fluidity.swf

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• The lipid tails will not associate with water
  molecules, and this allows the cell membrane to
  act as a physical barrier. The phospholipid
  bilayer also contains cholesterol, which makes
  the bilayer stronger, more flexible and
  permeable.

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3. Glycoprotein (Channel Carrier)

• Globular proteins have a structural role as well
  as a role in transporting ions in and out the
  cell-they are rounded and compact.

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4. Receptor Proteins

• Receptor Proteins are found on the bilayer, deal
  with communication, recognition and transport.
• Ex Binding of insulin Tell cell to increase
  intake of glucose.

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5. Carbohydrates Lipids

• Are found on the outer surface of the cell and
  have 3 major roles
• 1. important cell lubricants and adhesives
• 2. act as receptors for exracellular compounds
• 3. part of a recognition system that keeps the
  immune system from attacking its own tissues.

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Plasma Membrane (review)

• Controls what enters and leaves the cell. It
  contains the cell contents and protects the cell.
  
• composed of lipids
• hydrophobic lipid ends facing inward and the
  hydrophilic phosphate ends facing outward. Also
  called lipid bilayer.

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Functions of cell membrane

• The cell membrane or plasma membrane has four
  basic functions.

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Functions of cell membrane

• 1. Boundary between cell fluids
• Cytoplasm vs. extracellular fluid.

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• 2. Regulation of exchange
• Selects what goes in and what goes out (ions,
  waste, etc)

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• 3. Communication
• Senses environment and adjusts.

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• 4. Structural Support
• Gives cell support and shape.