Cells: The Basis of Life
Mevan Siriwardane
Mrs. Rolle’s Biology - Barringer High School
October 25, 2007
Background
 Microscopes
 Magnifies objects of small size
 Series of lens refracts a beam of light passing through
an object
 Light reflect of the object is focused to the eye to see a
larger image
Discovery of a Cell
 Earliest Microscopes
 Compound light microscope, mid-1600s
 Observations led to discoveries
 Hooke’s study of cork through microscope (1665)
 Leeuwenhoek saw living things in pond water (1674)
Development of the Cell Theory
 (Early 1600’s) - Invention of the first microscope
 1665 - Robert Hooke’s observation of cork under compound
microscope
 1674 - Anton van Leeuwenhoek discovers tiny living things in
pond water
 1838 - Matthias Schleiden states all plants are made of cells
 1839 - Theodor Schwann concludes all animals made up of cells
 1855 - Rudolph Virchow says that all cells come from existing cells
Cell Theory
 Observations and conclusions by many scientists
led to understanding of the cell
 Cell Theory:
 1) All livings things are made of cells
 2) Cells are basic units of structure/function
in living things
 3) New cells are produced from existing cells
Modern Microscopes
 Types
 Light microscope (400-1000X)
 Confocal/Fluorescence microscope (500X)
 Electron microscope (1000-10000X)
Basics of the Cell
 Separated from outside world
 Cell membrane
 Stores DNA for biological information
 DNA stored in nucleus depending of type
of cell
Types of Cells
 Prokaryotes
 Very ancient
 Very small and simple
 Bacteria
 No nucleus
 Eukaryotes
 Larger and more complex
 Organized structures
 Contains a nucleus
Prokaryotes vs. Eukaryotes
What is the Nucleus?

Control center
–
Contains DNA -> Coded set of instructions

Instructions for making molecules like proteins
Cell Structure and Function
Nucleus
 Eukaryotic Cell (Animal Cell)
Cytoplasm
 Divided into two parts: nucleus and cytoplasm
 Contains many functional “little organs” or
organelles
1.
2.
3.
4.
5.
6.
Nucleolus
Nucleus
Ribosome
Vesicle
Rough ER
Golgi Apparatus
7.
8.
9.
10.
11.
12.
Cytoskeleton
Smooth ER
Mitochondria
Vacuole
Cytoplasm
Lysosome
Cell Structure and Function
 Eukaryotic Cell (Plant)
Review
 http://www.wiley.com/legacy/college/boyer/0470003790/animation
s/cell_structure/cell_structure.htm
Closure