1. The document discusses cell structure and function, outlining the key components of eukaryotic cells including organelles like the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and cytoskeleton. 2. It describes the differences between prokaryotic and eukaryotic cells, and introduces the cell theory which states that all living things are composed of cells, cells are the basic units of structure and function, and new cells are produced from existing cells. 3. The final sections cover cell boundaries like the cell membrane and cell wall, transport mechanisms like diffusion, osmosis, facilitated diffusion and active transport, and

1. Cell Structure and
Function
Chapter four

2. The Discovery of the Cell
• Robert Hooke – first to see
and identify cork “cells.”
7-1

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
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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)
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5. Eukaryotic Cell Structure
• Organelles – structures in a
cell that act like “little organs.”
• Cytoplasm – the jelly-like
fluid where the organelles
“float.”
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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.
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7. Inside the Nucleus
Nucleolus
Chromatin
Nuclear Envelope
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8. Ribosomes
• Ribosomes – made of RNA
and protein. Make Proteins!
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9. Ribosomes
Ribosome
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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
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11. Endoplasmic Reticulum (ER)
Rough ER
Smooth ER
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12. Golgi Apparatus
• Golgi Apparatus – modifies,
sorts, and packages proteins.
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13. Golgi Apparatus
Golgi Apparatus
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14. Lysosomes
• Lysosomes – small
organelles filled with enzymes.
– Digest molecules to be used by
the cell.
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15. Vacuoles
• Vacuoles – store materials.
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16. Vacuoles
Vacuoles
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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!”
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18. Mitochondria
Mitochondria
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19. Chloroplasts
• Chloroplasts – organelles
that capture energy from
sunlight and convert it into
chemical energy.
(Photosynthesis)
– Found only in plants.
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20. Chloroplasts
Chloroplast
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21. Cytoskeleton
• Cytoskeleton – helps cell to
maintain shape, move, and
move organelles.
• Centrioles – help organize
cell division. Not found in
plants.
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22. Cytoskeleton
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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.
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24. Cell Membrane
• Controls what enters/leaves
cell, provides
support/protection.
• Lipid Bilayer – double-
layered sheet of
phospholipids.
Two layers!
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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.
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26. Osmosis Practice
90% H2O
10% NaCl
Concentrations are
equal, so no net 90% H2O
movement of water! 10% NaCl
Cell
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27. Osmosis Practice
80% H2O
20% NaCl
Concentration of
water is greater in 90% H2O
the cell than out, so 10% NaCl
Cell
water will move out!
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28. Osmosis Practice
90% H2O
10% NaCl
Concentration of
water is greater 80% H2O
outside the cell than 20% NaCl
Cell
in, so water will move
In!
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29. 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
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30. Facilitated Diffusion and Active
Transport
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31. Organization in Multicellular
Organisms
Cells
Tissues
Organs
Organ System
Organism
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