Cells

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Cells
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4.1 Discovery of the Cell

• The truth is, the science of Nature has already
  been too long made only a work of the brain and
  the fancy. It is now high time that it should
  return to the plainness and soundness of
  observations on material and obvious things.
  Robert Hooke Micrographia 1665

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The Cell

• Cell- the smallest unit that carries out all life
  processes

• Unicellular-
• one celled critters

• Multicellular-
• 2 celled critters

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Cell size is limited by the surface area to
volume ratio
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Cell Size

• The longest cell is 2 Meters long.

• The largest is the . . .

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Cell discovery
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Robert Hooke

• English
• Looked at cork cells in 1665

I could exceedingly plainly perceive it to be
all perforated and porous, much like a
Honey-comb
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Anton van Leeuwenhoek

• Dutch
• First to observe living cells

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Schleiden Schwann

• Botanist
• All Plants have cells

• Zoologist
• All animals have cells

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Virchow

• Cells only come from other cells

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Cell Theory

1. All living things are composed of cells
2. Cells are the basic unit of structure
3. Cells only come from other living cells

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Cell Membrane

• Boundary of the cell
• Made from a Phospholipid bilayer
• Selectively Permeable

Hydrophilic Hydrophobic
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Cytoplasm

• Jelly like substance found inside the cell
• Contains Water, Salts and Organic Molecules
• In constant motion

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Nucleus

• Contains the DNA
• Information center of the cell
• Nucleolus
• Ribosome
• components are
• made here

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Ribosome

• Site of Protein Synthesis

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Endoplasmic Reticulum

• Folded sacs and tunnels
• Two types
• Smooth
• Intracellular highway
• Rough
• Covered with ribosomes which make proteins

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Golgi Apparatus

• Processes, Packages and secretes proteins for the
  cell
• Stacks of membranes

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Mitochondria

• Power house of the cell
• Have their own DNA
• Respiration occurs here

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Lysosomes

• Digestive organelle
• Contains enzymes that breakdown food particles
  and old worn out organelles

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Cilia and Flagella

• Both used in movement
• Cilia
• Short hair-like structures
• Flagella
• Whip like tail

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Exclusive to Plants

1. Cell Wall
2. Vacuole
3. Chloroplast

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Cell Wall

• Rigid covering of plant cells
• Gives cell strength

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Vacuoles

• Stores enzymes and waste products
• Similar to lysosomes in animals

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Chloroplast

• Contain chlorophyll
• Where plants absorb sunlight
• Site of photosynthesis