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Cell Biology Preview

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Title: Cell Biology Preview


1
Chapter One
  • A Preview Of Cell Biology
  • By Arkan Omais

2
Introduction
  • The cell is the basic unit of biology
  • Cells are constantly changing
  • The convergence of cytology, genetics, and
    biochemistry has made modern cell biology one of
    the most exciting dynamics and disciplines in
    biology

3
The Cell Theory A Brief History
  • Robert Hooke (1665) observed compartments in
    cork, under a microscope, and first named the
    cells
  • He had observed the compartments formed by cell
    walls of dead plant tissue

4
Advances in Microscopy Allowed Detailed Studies
of Cells
  • Two factors restricted progress in early cell
    biology
  • Microscopes had limited resolutions, or resolving
    power ( ability to see fine detail)
  • The descriptive nature of cell biology the focus
    was on observation, with little emphasis on
    explanation

5
Compound Microscopes
  • By the 1830s, compound microscopes were used
    having the following features
  • Contain two lenses
  • Both magnification and resolution were improved
  • Structures only 1µm in size could be seen

6
The Cell Theory Applies to All Organisms
  • Using a compound microscope, Robert Brown
    identified the nucleus, a structure inside plant
    cells
  • Matthias Schleiden concluded that all plant
    tissues are composed of cells
  • Thomas Schwann made the same conclusion for
    animals

7
The Cell Theory
  • In 1839, Schwann postulated the cell theory
  • All organisms consist of one or more cells
  • The cell is the basic unit of structure for all
    organisms
  • Later, Virchow (1855) added
  • 3. All cells arise only from preexisting cells

8
The Emergence of Modern Cell Biology
  • Three strands of biological inquiry weave into
    modern cell biology
  • Cytology focuses mainly on cellular structure and
    emphasizes optical techniques
  • Biochemistry focuses on cellular morphology and
    function
  • Genetics focuses on information flow and heredity
    and includes sequencing of the entire genome (all
    of the DNA) and the numerous organisms

9
Cellular Dimensions
  • Cells are measured in micrometer µm also called a
    micron where 1µm 10-6 m
  • Plant and animal cells are larger than bacterial
    cells in size by 10- 20 times
  • Organelles are comparable to bacterial cells in
    size

10
The Light Microscope
  • Earliest tools of cytologists
  • Allowed identification of nuclei, mitochondria,
    chloroplasts within cells
  • Light microscopy is also called brightfield
    microscopy because white light is passed directly
    through a specimen

11
Improvements of Microscopy
  • Microtome (1800s) allowed preparation of very
    thin slices of samples
  • Usage of dyes for staining cells
  • Improving the limit of resolution
  • A greater resolving power
  • Electroscope

12
Meanings
  • Morphology shape or structure
  • Electroscope a scientific instrument that uses
    electric beams to detect and observe the samples
    sharply
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