Microscopes and Cells: History

1
Microscopes and Cells History
Robert Hooke

• In 1663, __________ coined the term cells
• 10 years later, _________________ observed
  bacteria and protozoa
• In 1833, __________ observed and coined the term
  nucleus

Anton van Leeuwenhoek
Robert Browne
2
Cell Theory History
Guten Tag, Dr. Shwann
Guten Tag, Dr. Schleiden
It appears we have come up with a very similar
theory

• In 1838 (and 1839) German scientists,
  ________________ ________________ independently
  came up with the Cell Theory

Matthias Schleiden
What shall we call this theory?
Theodore Schwann
3
Cell Theory

• All living things are composed of one or more
  cells.
• Cells are organisms' basic units of structure and
  function.
• Cells form by free-cell formation, similar to the
  formation of crystals (spontaneous generation).

Do you agree?
4

• In 1855, German physician Rudolph Virchow
  discovered that

I do believe that all cells must come from
pre-existing cells.
5
Cell
6
Prokaryotic Cells
DNA (Nucleoid)
Ribosomes
Plasma Membrane
Cytoplasm
Flagellum
Flagella
TEM of a bacterium
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Differences and similarities between Prokaryotes
and Eukaryotes

• Differences
• Prokaryotes lack
• True nucleus
• Membrane bound organelles
• Prokaryotes are much smaller than eukaryotes
  (prokaryotes are 1 10 ?m)

• Similarities
• Both have
• DNA
• Cytoplasm
• Ribosomes
• Plasma Membrane

8
Plant and Animal Cells
Comparing and Contrasting Organelles in
Eukaryotic Cells
9
Plasma Membrane

• A cell boundary that controls the movement of
  substances into and out of the cell
• Often folds multiple times to create extensions
  called microvilli
• In all cells

10
The Plasma Membrane
Carbohydrate side chains
Proteins
Hydrophilic Region
Hydrophobic Region
Hydrophilic Region
Phospholipid
TEM of a red blood cell
11
Cell Wall

• An inflexible barrier that provides support and
  protects the plant cell
• Located outside of the cell membrane
• In plant and prokaryotic cells

12
CytoplasmCytoskeleton

• Jellylike fluid that fills the cells and supports
  organelles (cell parts)
• The cytoskeleton is the framework within the
  cytoplasm
• In all cells

13
Nucleus

• The brain or control center of the cell.
• Contains DNA, that hold directions for cell
  division, growth, and making of proteins
• In plant and animal cells

14
Nucleolus

• Found inside the nucleus, this structure makes
  ribosomes
• In plant and animal cells

15
Ribosome

• Makes proteins for the cell
• Can be found free in the or attached to the
  Rough Endoplasmic Reticulum
• Very, very small
• In all cells

16
Centriole

• Occur in pairs, may help create spindle fibers
  that assist in cell division
• Found near the nucleus
• In animal cells

17
Mitochondrion

• The powerhouse of the cell that makes energy
• In plant and animal cells

18
Chloroplast

• Contains chlorophyll for photosynthesis so that
  plant cells can make sugar (food) for itself
• In plant cells only

19
RoughEndoplasmic Reticulum (RER)

• A highly folded membrane with ribosomes on the
  surface
• Assists in transport of substances such as
  proteins
• Proteins are made by the ribosomes on its surface
• In plant and animal cells

20
Smooth Endoplasmic Reticulum

• Similar to the RER, but w/o ribosomes on its
  surface
• Involved in detoxification of drugs and poisons
• Makes fats, and metabolizes carbohydrates
• In plant and animal cells

21
Golgi Apparatus

• Collects, modifies, and packages proteins so they
  can be delivered to different parts of the cells
• In plant and animal cells

22
Lysosome

• Contains digestive enzymes for the breakdown of
  waste
• Animal cells only

23
Vesicle

• Pinches off from the golgi
• Carries proteins and other substances to
  different parts of the cell
• In plant and animal cells

24
Vacuole

• A membrane-bound vesicle that temporarily stores
  materials such as water, waste, and nutrients
• In all cells
• Large in plant cells, small in animal cells

25
Cilia and Flagella(12)

• Cellular projections that aide in movement
• Flagella are longer move in a snake-like
  motion.
• Cilia are shorter, more numerous and move back
  forth

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Microvilli (13)

• Projections from the cells surface that increase
  the surface area.

Microvilli
Microfilaments
Intermediate Filaments