Cellular Structure

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

Nucleus: FYI  Most cells contain only one nuclei;  Skeletal muscle = many  Mature RBCs = none

Nucleolus  Dense region that contains DNA/RNA  Synthesizes RNA and ribosomes

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

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

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

Mitochondria  The “powerhouse” of the cell.  They create food to obtain energy for cell activities.  Produces 95% of ATP

Mitochondria  # of mitochondria = energy level needed

Matrix

Cristae  Lots of folds in mitochondria

 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.

Ribosomes  Makes proteins in the cell. “Protein factories”- aka. protein synthesis  Contains RNA

Ribosomes  Free- floating: Proteins are made and enter in the cytosolProteins are made and enter in the cytosol  Fixed Proteins enter ER where they are modified and packaged for export.

Endoplasmic Reticulum (ER) 1. Synthesis 2. Storage 3. Transport

Synthesis  ER makes CarbohydratesCarbohydrates LipidsLipids

Storage  Storage of molecules that are absorbed from the cytosol.

Transport  Network of membranes. (Travel anywhere)

Smooth (SER)  Lack ribosomes (smooth)  Focus on making carbohydrates and lipids

Rough (RER)  Contain ribosomes (hence rough)  Focus on making proteins

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

Golgi Apparatus  Page 55 of text.  Example of exocytosis and membrane reconstruction.

Lysosomes  Digest worn out or unneeded cells and cell parts.

Lysosomes  Packages of digestive enzymes.  Fight pathogens  Why?????

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

Microtubules  Hollow tubes that give support and strength

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

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

Flagella  A tail like structure used for movement

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

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P Q S T U O N M L K

AKA: cell membrane

COLOR CODE (Page 52 new)  Glycoproteins: (Globular) G  Channel: H  Phospholipids Heads: A  Fatty acid tails: S  Carbohydrate (sugar)

1. Hydrophobic  “Dislike Water”  Two fatty acid tails

2. Hydrophilic  “Likes Water”  Non-lipid head

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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.

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.

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.

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.

Plasma Membrane (review) 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.

Functions of cell membrane  The cell membrane or plasma membrane has four basic functions.

Functions of cell membrane 1. Boundary between cell fluids Cytoplasm vs. extracellular fluid.

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

 3. Communication: Senses environment and adjusts.Senses environment and adjusts.

 4. Structural Support: Gives cell support and shape.Gives cell support and shape.