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Cells and Cell Organelles
History
Anton Van Leeuwenhoek
• The microscope was invented by Anton
Van Leeuwenhoek, a Dutch biologist in the
early 1600’s. Leeuwenhoek’s invention
allowed him to see tiny living organisms in
droplets of water.
Robert Hooke was the first person to name
cells.
Hooke was looking at cork under the
microscope and thought they looked like
the rooms monks lived in called cells.
Over the next 300 years…
Matthias Schleiden – stated that all plants are made of
cells. (1838)
Theodor Schwann – discovered that all animals are made
of cells too (1839).
Rudolf Virchow – stated that all cells arise from the
division of preexisting cells (1855).
Cell Theory
Three key statements
i. All organisms are made up of one or more
cells.
ii. The cell is the smallest living organizational
unit.
iii. All cells are produced from previously
existing cells.
b.
All cells appear to be descended from
the first cell which existed about 4 billion
years ago
For a species to exist, its reproductive
cells must be potentially immortal (no
aging).
2 type of cells
Prokaryotic cells
Eukaryotic Cells
Prokaryotic cells
• Prokaryotic cells are . . .
• (1)Smaller and more primitive.
(2)Have few organelles and
their organelles have no membranes. The
cell has no nucleus.
• (3)They are bacteria.
Eukaryotic Cells
Eukraryotic Cells are…..
(1)
More 1. More advanced, larger, and contain
organelles. These cells have a nucleus.
Organisms made of these cells include protists,
fungi, plants, and animals (including humans).
2.Organelles allow many activities to
take place within the same cell other reactions
take place on membrane surfaces and eukaryotic
cells have much more internal membrane surface
that prokaryotic cells
Organization of Organisms
Complex organisms can be organized as follow
Organism
Organs and organ systems
Tissues
Cells
Organelles
Molecules
b.
All cells appear to be descended from
the first cell which existed about 4 billion
years ago
For a species to exist, its reproductive
cells must be potentially immortal (no
aging).
Cell Membrane
- contains special fat molecules which keep
water from passing through
- controls what comes into and goes out of
the cell
- also has proteins stuck in it
- very important for homeostasis
- Selectively permeable
Cell Wall
- found in plants, bacteria, and fungi
- not living like the cell membrane
- because it is not living it requires pores for
things to get in and out.
- protects the plant cell and gives it strnegth
and structure
- because it is so strong the plant does not
need a skeleton
Cytoplasm
Also known as cytosol
• all the liquid which fills the cell
• mostly water
nucleus
•
•
•
•
controls the activities of the cell
contains the DNA (genetic information)
DNA is in the form of chromosomes
surrounded by the nuclear membrane
which is similar to the cell membrane
• the nuclear membrane controls what goes
in and out of the nucleus
Mitochondria
• release energy from the food we eat
• break down glucose and other molecules
for energy
Ribosome
• - make protein for the cell
• - most cells have 1000s of ribosomes
• - some proteins stay inside the cell, some
proteins leave the cell
Lysosome
- lysosomes break apart worn out cell parts
- like a little recycling center
- the parts are then reused to make new cell
parts
Chloroplasts
- contain a green pigment called chlorophyll
- this pigment absorbs light from the sun
- the chloroplasts make glucose (the main
food) for the plant
- this process is called photosynthesis
Vacuole
- the vacuole is used for storing things inside
the cell
- plant cells usually have very large vacuoles
that they use to store water
- the vacuoles of animal cells are not as large
but they have many more