Cells

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Cells

• November 19, 2009

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• I. Cells building blocks of all life
• A. Discovered in 1600s
• 1. After Microscope was invented
• 2. Named by Hooke

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• II. Cell Theory
• A. All living organisms are made of cells
• 1. One or more
• Humans, elephants, redwood trees, amoebas,
  bacteria, mushrooms
• B. Cells basic unit of structure in function of
  organism
• Bone cells
• Fat cells
• Muscle cells
• Leaf cells
• C. All cells come from other cells
• 1. Reproduction cell division
• 2. We start as one cell fertilized egg

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• III. Types of cells (types of organisms)
• A. Prokaryotic
• 1. Most primitive life form
• bacteria and blue green bacteria
• 2. Oldest fossils 3.75 billion years old
• 3. Do not have nucleus
• 4. Do not have organelles with membranes
• 5. DNA is in form of loop or ring

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• B. Eukaryotic
• 1. More advanced/complex have nucleus
• 2. Includes protists,fungi, plants, and animals
• 3. Oldest fossils 1.9 billion years old
• 4. Have nucleus
• a) Double membrane
• b) DNA enclosed inside
• 5. Have organelles made of membranes
• a) Mitochondria
• b) Chloroplasts
• c) Vacuoles
• d) Many others
• 6. DNA is in linear form

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• IV. Geography of Eukaryotic Cell
• A. Plasma membrane
• 1. Outer layer of cell
• 2. Controls what goes in or out of cell
• B. Nucleus Has double membrane with pores
• 1. Center of cell
• 2. Contains DNA
• control center of cell
• C. Cytoplasm
• 1. Region
• Area between nucleus and cell membrane
• Filled with cytosol (jelly) and organelles

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• V. How cells are studied
• A. Microscopy
• 1. Principle of the Light Microscope
• a) Light is focused on specimen
• b) Light passed through specimen
• c) Magnification how much larger an object is
  made to appear compared to its larger size
• d) Resolving power minimum distance between two
  points that can still be seen
• e) Resolution of a light microscope is limited by
  the wavelength of light
• -Highest magnification in a light microscope
  1500X

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• 2. Principle of a Transmission Electron
  Microscope (TEM)
• a) Electron beam is aimed at a thin section of
  specimen
• b) Electrons are focused by using electromagnetic
  lenses
• c) Image is focused into screen or film
• d) Used to study internal cellular
  ultra-structure
• e) Resolving power is inversely related to
  wavelength
• 3. Principle of a scanning electron microscope
• a) Electron beams scans the structure of the
  specimen and gives a 3D image
• 4. Cell Fractionation centrifuging broken cells
  at various speeds to isolate parts of different
  sizes
• a. Heavier organelles sink to bottom

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• VI. The Nucleus
• A. Structure
• 1. Nuclear membrane
• a. Double Membrane
• b. Has pores
• 2. Chromosomes
• a. Long threads of DNA
• b. Each species has certain amount
• Humans 46
• 3. Nucleolus spherical region in the nucleus
• a) Makes ribosomes
• b) May have two or more per cell
• B. Function
• 1. Control Center
• 2. Stores DNA

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• VII. Ribosomes
• A. Structure
• 1. Made of protein RNA
• B. Function
• 1. Help make proteins
• C. Made in the nucleolus
• D. Free ribosomes ribosomes in cytosol
• E. Bound ribosomes ribosomes attached to E.R.

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• VIII. Endoplasmic Reticulum (ER)
• A. Structure
• 1. Extensive network of membranes, tubules, and
  sacs highly folded
• 2. Connected with the outer membrane and the
  nuclear membrane
• B. Smooth ER
• 1. Lacks ribosomes
• 2. Makes lipids, phosolipids and steroids
• C. Rough ER
• 1. Has ribosomes
• 2. Makes proteins for export

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• IX. The Golgi Apparatus
• Structure
• 1.Made of membrane sacs
• 2. Arranged in stacks
• B. Function
• 1. Package materials for export (secretion)
• 2. Makes carbohydrates

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• Lysosomes
• A. Membrane sac filled with digestive enzymes
• 1. Break down food vacuoles
• 2. Break down worn out cell parts
• 3. Break down worn out cells

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• XI. Vacuoles
• A. Membrane-enclosed sac
• B. Types
• 1. Food vacuole
• 2. Contractile vacuole
• 3. Central vacuole found in most mature plant
  cells
• a) Stores materials

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• XII. Mitochondria
• A. Structure
• 1. Has two membranes
• a) Smooth outer membrane
• b) Highly folded inner membrane
• B. Function
• 1. Site of cellular respiration powerhouse
• 2. Site where ATP is made

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• XIII. Chloroplasts
• A. Structure
• 1. 3 membranes
• Inner
• Outer
• Thylakoid
• B. Function
• 1. Site of photosynthesis
• 2. Found in eukaryotic algae, leaves and other
  green plants

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• XIV. The Cytoskeleton A network of fibers
  throughout the cytoplasm that forms a framework
  for support and movement
• A. Mechanical Support
• B. Enables a cell to change shape
• C. Associated with cell movement
• 1. Microtubules
• -Straight hollow tubes
• -Separation of chromosomes during cell division
• -Make up centrioles in animal cells

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• Centriole composed of nine sets of triplet
  microtubules arranged in a ring
• Cilia and Flagella
• May propel single-celled organisms
• Draw fluid across the surface of cells
• Structure of cilia and flagella
• Are extensions of plasma membrane with a core of
  microtubules

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• XV. Endosymbiosis (Endosymbiotic Hypothesis)
• A. States that eukaryotes arose from groups of
  prokaryotes living together
• 1. Many examples of symbiosis in nature
• E. coli in large intestine
• Skin mites
• 2. Some present day organelles may have arose
  from ancient prokaryotes