2. The Discovery of the Cell
• Robert Hooke – first to see
and identify cork “cells.”
3. The Cell Theory
• Cell Theory:
2. All living things are
composed of cells.
Schleiden 3. Cells are the basic units of Schwann
structure and function in
living things.
4. New cells are produced from
existing cells.
Virchow
4. Prokaryotes and Eukaryotes
• Nucleus – large membrane-
enclosed structure that
contains the cell’s genetic
information.
• Prokaryotes – cells that do
not contain nuclei. (Bacteria)
• Eukaryotes – cells that
contain nuclei. (All other
organisms)
5. Eukaryotic Cell Structure
• Organelles – structures in a
cell that act like “little organs.”
• Cytoplasm – the jelly-like
fluid where the organelles
“float.”
6. Inside the Nucleus
• Nuclear Envelope – membrane
that surrounds the nucleus.
• Chromatin – consists of DNA
wrapped around proteins. “Ball of
string”
• Chromosomes – condensed
string-like structure that forms from
DNA just before the cell divides.
• Nucleolus – structure within the
nucleus that makes ribosomes.
10. Endoplasmic Reticulum (ER)
• Endoplasmic reticulum –
internal membrane system of
the cell.
– Lipids, proteins, and other
products are made here.
– Rough ER – has ribosomes
– Smooth ER – no ribosomes
17. Mitochondria
• Mitochondria – organelle that
converts chemical energy
stored in food into compounds
that are more convenient for
the cell to use.
– “Powerhouse of the Cell!”
19. Chloroplasts
• Chloroplasts – organelles
that capture energy from
sunlight and convert it into
chemical energy.
(Photosynthesis)
– Found only in plants.
21. Cytoskeleton
• Cytoskeleton – helps cell to
maintain shape, move, and
move organelles.
• Centrioles – help organize
cell division. Not found in
plants.
23. Cell Boundaries
• Cell membrane – thin, flexible
membrane that surrounds the
cell.
• Cell walls – rigid layer around
the membrane found only in
bacteria, fungi and plants.
24. Cell Membrane
• Controls what
enters/leaves cell,
provides
support/protection.
• Lipid Bilayer – double-
layered sheet of
phospholipids.
Two layers!
25. Diffusion and Osmosis
• Diffusion – movement of
particles from an area of high
to low concentration.
• Osmosis – the diffusion of
water through a selectively
permeable membrane.
– Water will move into/out of a cell
to equalize concentrations.
26. Facilitated Diffusion and Active
Transport
• Facilitated diffusion – when
the plasma membrane “helps”
particles pass through protein
channels.
– No energy used.
• Active transport – when the
plasma membrane uses
energy to move particles
against a concentration
gradient.
– Uses Transport Proteins