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Cell structure and function
Discovering cells
• Robert Hooke discovered cells
• Used a compound microscope
Discovering cells
• Robert Hooke looked at cork under a
microscope
– Reminded him of small rooms monks used
called cells
Cell Theory
• Mathias Schleiden found that all plants
have cells
• Theodor Schwann found that all animal
have cells
3 main ideas of cell theory
1. All organisms are composed of one or
more cells
2. Cell is the basic unit of structure and
organization of organisms
3. All cells come from pre-existing cells
2 major kinds of cells
• Prokaryotic
• Eukaryotic
Prokaryotic cell structure
Eukaryotic cell structure
Prokaryotic vs. Eukaryotic
• Prokaryotic cells are simple cells.
– The first cells. Only contain DNA, RNA and
ribosomes along with cell wall and plasma
membrane. They are much smaller than
eukaryotic cells. Ex: bacteria cells
• Eukaryotic cells are more complex cells.
– These cells are larger. They contain
organelles; nuclues, mitochondria, vacuole,
chloroplast, etc. Ex: animal and plant cells.
Organelles
• Organelle: specialized subunit within a
cell that has a specific function
Nucleus
• Control center.
Cell Wall
• Tough, fairly rigid layer that surrounds
some types of cells
Plasma membrane
• Biological membrane separating the
interior of the cell from the exterior of the
cell
Mitochondria
• Energy powerhouse
Vacuole
• Cell storage unit
Chloroplast
• Converts sunlight into food (sugar) in
plants
Ribosomes
• Protein builders
Comparing types of cells
Prokaryotic
•
•
Does it have a nucleus?
– no
Does it have membrane bound
organelles?
– no
Eukaryotic
•
Does it have a nucleus?
– yes
•
Does it have membrane bound
organelles?
– yes
What kind of organisms is it
found in?
– Animals, Plants, Fungi,
Protists
•
•
What kind of organisms is it
found in?
– bacteria
•
Examples
– E.coli
•
Examples
– Red blood cell
•
Which cell evolved first?
– prokaryotes
•
Which cell evolved first?
– Prokaryotes
Plasma Membrane
• Homeostasis:
regulation of internal
environment
(balance)
• Plasma Membrane:
Boundary between
cell and its
environment
Maintaining Balance
• Plasma membrane acts as a selectively
permeable membrane
– What does that mean?
• Allows some stuff to come in, and keeps
some stuff out
• Helps cell maintain homeostasis!
Structure of the plasma membrane
• How many layers is it?
• What is it mostly made
of?
• Why is it called the fluid
mosaic model?
• What else is it made up of
besides phospholipids?