Transcript The Cell Theory

The Cell Theory
Biology 11
Cell Biology
Chapter 1
The Cell
pages 8-10
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smallest living unit
Basic building block of organisms
Human body – 100 trillion cells
Different cells are specialized to preform
different tasks
Nerve Cells
• Transmit messages to the
body about our surroundings
and enable us to respond.
• Vision, hearing, taste, smell
and touch all depend on
nerves.
Muscle Cells
• Capable of rapid contraction.
• Grouped together to form our
muscle groups.
Red Blood Cells
• Transport of Oxygen
White Blood Cells
• Defense against disease.
Special Receptor Cells
• Communicate messages to nerves for
relay to nerve centres like the brain.
Our Body – a living ecosystem of
cells
• E. coli bacteria in our “gut”.
• We breathe in plant spores and pollen.
• Microbes and microscopic animal eggs on
the food we eat.
• All made of cells!
• Outside has cells too – fungus and
bacteria.
Cells in Daily Life
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Yogurt bacteria
Sour milk bacteria
Cheese processing
Yeast cells for bread and beer making
Leather tanning processes
All cells ………
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Digest nutrients
Excrete wastes
Synthesize needed chemicals
reproduce
Cells are….
• The basic unit of all living things!
• Grouped together to form tissues and
organs.
Cell History
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Robert Hooke, 1665, borrowed the word cell (reminded him of the “cells” in
a monastery) to describe the honeycomb shape and structure of a thin slice
of cork he observed under a primitive microscope.
Robert Hooke
Neglected Hooke
Anton Van Leeuenhoek, 1674 An Unlikely Scientist, made microcsopes
and observed blood cells, bacteria and single celled organisms.
Robert Brown, 1831, described the nucleus
Theodor Schwann and Mathias Schleiden, 1838, plant and animal tissue
composed of cells
Louis Pasteur, – Very Important Person! studied microorganisms.
Rudolph VIrchow, 1858, “All cells come from preexisting cells.”
Modern Cell Theory
• All living things are composed of one or
more cells.
• The cell is the smallest entity that retains
the properties of life.
• New cells arise only from cells that already
exist.
• An expansion….More to the story!