Warm Up:

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Warm Up

• What are the three parts of cell theory?
• All organisms are composed of cells
• The cell is the structural unit of life
• Cells arise only from previously existing cells

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Cell Theory
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The Microscope

• Dutch lens grinder
• Invented the first compound microscope around 1600

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The CELL
Robert Hooke 1635-1703

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• Observed cork under microscope-1655
• Noted many chambers that he called cells
• Publishes Micrographia

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• Designed his own microscope- 1683
• Discovered single celled protozoan

Anton van Leeuwenhoek
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The Cell Theory

• 1830- German scientists Schleiden and Schwann
  develop Cell Theory
• All organisms are composed of cells
• The cell is the structural unit of life
• Cells arise only from previously existing cells

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• Henri Dutrochet
• "The cell is the fundamental element of
  organization"

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• In 1858, Rudolf Virchow concluded that all cells
  come from pre-existing cells thus completing the
  classical cell theory.

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Cell Types

• Prokaryotic
• before nucleus
• No membrane bound organelles
• Lacks nucleus
• Most unicellular organisms are prokaryotic
• Monera

• Eukaryotic
• true nucleus
• Membrane bound organelles
• Contain nucleus
• Most organisms are made of these cells
• Plant cells, human cells

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Cell Types
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Organelles

• Specialized part of the cell
• little organs

Animal Cell
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Plasma or cell membrane

• 1. Forms a thin, flexible boundary between a cell
  and its environment
• 2. Selectively permeable
• -Allow some substances to pass through while
  keeping others out

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Plasma membrane

• Phospholipid bilayer
• hydrophilic head-water loving
• Hydrophobic tail-water fearing

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Plasma membrane-other components

• Moving with and among phospholipids
• 1.Proteins
• 2.Carbohydrates
• 3.Cholesterol
• Fluid mosaic- bilayer creates a sea in which
  these molecules can move around

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Plasma membrane

• Proteins
• Receptors- proteins on outer surface that serve
  to transmit signals to inner cell
• Structural-proteins on inner surface that serve
  to anchor the plasma membrane to the inner cell
• Transport- proteins that span the entire
  membrane, moving needed substances or waste in
  and out

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Plasma membrane

• Cholesterol- positioned among phospholipids-
  helps prevent fatty acid tails from sticking
  together
• Carbohydrates- attached to proteins, often stick
  out of plasma membrane- helps cell identify
  signals

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Organelles within the cell-Eukaryotes

• Each organelle has a unique structure and
  function
• Allow cell to carry out essential processes

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• Cytoplasm
• clear fluid
• jelly-like

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Nuclear Structures

• Nucleus
• control center
• contains DNA
• Nucleolus
• small dense region
• makes ribosomes
• Nuclear Membrane
• protects the nucleus

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Ribosomes

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Ribosomes

• The factories of cells
• Involved in protein synthesis

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Endoplasmic Reticulum
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Endoplasmic Reticulum

• Extensive membrane system of folded sacs and
  interconnected channels- large surface area for
  cellular functions to take place
• Continuous with outer nuclear membrane
• Serves as the site for protein and lipid
  synthesis
• Two types
• Rough (ER)- has ribosomes on it that produce
  proteins for export
• Smooth (ER)- lacks ribosomes and is involved in
  membrane lipid synthesis

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Golgi apparatus

• Flattened stack of membranes
• Modifies, sorts, and packages proteins into sacs
  called vesicles
• Vesicles can than fuse with the cells plasma
  membrane to release proteins to the environment
  outside the cell or they can be used internally

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Golgi apparatus
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Mitochondria

• Powerhouse of cell
• Site of aerobic respiration
• Sugaroxygen ATPcarbondioxidewater

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Lysosomes

• Lysosomes- found only in animal cells
• Clean-up crew
• Contain enzymes for use in the breakdown of
• worn-out organelles
• Food particles
• Bacteria and viruses

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Centrioles

• Groups of microtubules that function during cell
  division
• Usually located near the nucleus
• Present in animal cells and most protists

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Cilia and Flagella-cell movement

• Some eukaryotic cells have these, composed of
  microtubules
• Cilia- short numerous projections that look like
  hairs- oar like motion
• Flagella- longer, less numerous-whip motion

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What about Plant cells?

• Similar in many respects to animal cells
• Differences
• Cell wall
• Chloroplasts
• Vacuoles-large

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Cell Wall

• Thick, rigid, mesh of cellulose fibers
• Rigid cell walls allow plants to stand at great
  heights

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General Sherman- largest living thing
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Chloroplasts

• Site of Photosynthesis
• Converts solar energy to chemical energy-ATP and
  sugars
• Chlorophyll green pigment which captures light

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Vacuoles

• Membrane bound vesicle
• Used to store food, waste products, enzymes, and
  other materials needed by the cell
• Some animal cells contain vacuoles- they are much
  smaller than those in plants

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Comparing Plant Animal Cells
Structure Animal ? Plant?
cell membrane
cell wall
nucleus
ribosomes
E.R.
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golgi
lysosomes
vacuoles
mitochondria
chloroplasts
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Comparing Plant Animal Cells
Structure Animal ? Plant?
cell membrane Yes Yes
cell wall No Yes
nucleus Yes Yes
ribosomes Yes Yes
E.R. Yes Yes
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golgi Yes Yes
lysosomes Yes No
vacuoles Small Large
mitochondria Yes Yes
chloroplasts No Yes
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Cellular Transport

• Moves substances within the cell and moves
  substances into and out of the cell
• Diffusion/osmosis
• Facilitated diffusion
• Active transport

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Diffusion

• Random motion from high concentration to low
• No energy required
• Rate of diffusion is affected by
• Concentration
• Temperature
• Pressure

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Osmosis

• The diffusion of water across a selectively
  permeable membrane
• If cell is in a solution that has a lower
  concentration of solute/waterhypotonic
• If cell is in a solution that has a higher
  concentration of solutehypertonic
• If cell is in a solution that has an equal
  concentration of soluteisotonic

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Facilitated Diffusion

• Uses transport proteins to move ions and small
  molecules across the plasma membrane
• Uses concentration gradient for energy
• Conformational change in protein allows passage

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Active Transport

• Moves substances against concentration gradient
• Accomplished by protein pumps
• Na/K ATPase pump is an example
• Requires energy(ATP)

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Transport of Large Particles

• Endocytosis- cell surrounds a substance with
  plasma membrane- pinches it of to form vacuole
• Exocytosis- cell releases a substance at plasma
  membrane
• Both processes require energy(ATP)