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4-1 Introduction to the Cell

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... Robert Hooke Observed cells in cork. Coined the term – PowerPoint PPT presentation

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Title: 4-1 Introduction to the Cell


1
4-1 Introduction to the Cell
2
Important events in the discovery of the cell and
the development of the cell theory..
3
1665 Robert Hooke
  • Observed cells in cork.
  • Coined the term "cells.

Cork Cells
4
1673- Anton van Leeuwenhoek
  • Created a powerful microscope

5
1827-33 - Robert Brown
  • -noticed that pollen grains in water jiggled
    around called Brownian motion
  • -discovered the nucleus

Nucleus
Human Cheek Cell
6
1838 - Matthias Schleiden
  • A botanist who concluded that all plants are made
    of cells.

Typical Plant Cell
7
1839 - Theodor Schwann
  • A zoologist who concluded that all animals
  • are made of cells.

Nerve Cells
8
1855 - Rudolph Virchow
  • A physician who did
  • research on cancer cells and concluded
  • Omnis cellula e cellula.
  • All cells are from other
  • pre-existing cells.

9
The Cell Theory
  • 1. All living things are composed of one or more
    cells.
  • 2. Cells are the basic units of structure and
    function in an organism.
  • 3. Cells come only from existing cells.

10
Cells are Diverse
  • both in size, shape, and internal organization.

11
Why Are Cells So Small?
  • Transport- Cell volume to surface area ratios
    favor small size.
  • Control- Nucleus to cytoplasm consideration.
  • Metabolic requirements-
  • ..well come back to this later.

12
How small can a cell be?
  • Mycoplasmas - bacteria that are 0.1 to 1.0 mm.
    (1/10 the size of
    regular bacteria).
  • Note 1.0 mm one millionth of a meter

13
All cells have
  • Plasma (cell) Membrane
  • Nucleus (eukaryotes only)
  • Cytoplasm (an area)
  • Organelles (structures with
  • specialized functions)

14
Cell Types
  • Prokaryotes- simple cells that do not have
    internal membranes
  • example bacteria
  • Eukaryotes- more complex cells that do have
    internal, membrane-bound structures
  • examples plants and animals

15
Timeline
Prokaryotic Organisms First appeared 3.5
BYA include bacteria and cyanobacteria
Eukaryotic Organisms First appeared 2.0
BYA include protists, fungi, plants and animals
16
Prokaryotes
  • Lack a nucleus and other membrane bounded
    structures.
  • Have small ribosomes
  • DNA is not organized into chromosomes
  • Flagella are not made of microtubules and does
    not have a 92 structure
  • Cell walls are made of peptidoglycan, not
    cellulose

17
Eukaryotes
  • Have a nucleus and other membrane bounded
    structures.
  • Have large ribosomes
  • DNA is organized into chromosomes
  • Flagella are made of microtubules and have a 92
    structure
  • Cell walls are made of cellulose

18
Examples
Prokaryotic
Eukaryotic
Nucleus
19
Eukaryotic
Prokaryotic
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