What is a cell?
Cell
– Basic unit of
structure and
function in all
living things
Cell Study and Discovery
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• Matthias Schleiden (1888) – All plants are made up of
cells
• Theodore Schwann (1889) – All animals are made up
of cells
• Rudolph Virchow (1889) – Cells come from preexisting cells.
The Cell Theory
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All living things are made up of cells
Cells are the basic unit of structure
and function in all living things
Cells come from pre-existing cells
Shape – Form reflects function.
Red Blood Cells are like tubes at Sesame
Place so they flow easier
Nerve cells are like electrical wires
Cheek cells (Epithelial cells) are flat to act like
a shield
White Blood cells are amoeboid shaped to
move and squeeze into all areas
Types of cells
1. Prokaryotic cells
– Primitive cells – “before
the nucleus”
– No membrane bound
organelles
– No nucleus
– Found in Eubacteria and
Archaeabacteria
– Cell wall, cell membrane,
cytoplasm, DNA &
ribosomes
2. Eukaryotic
“True nucleus”
– Have membrane –
bound organelles
– All other
kingdoms but
Archaeabacteria &
Eubacteria
– Organelles such
as: Mitochondria,
endoplasmic
reticulum,
vacuoles,
lysosomes, and
chloroplasts.
Comparing the Two
Cytoplasm
DNA
Cell Membrane
Structures common to both Prokaryotic and
Eukaryotic cells
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Cell Membrane
Ribosomes
DNA
Cytoplasm
Cell Walls (not in Animal or some Protist
cells though!)
Organelle – small structures in cells that have
a specific function
Cell Organelles and Their Functions
1. Cell Membrane
– Outermost boundary in all Animal Cells.
- Separates the cell’s internal environment
from the external environment.
- Allows for the passage of some
substances based on size and
concentration
- Selectively Permeable due to pores being
present
Made up of a bilipid layer (lipid bilayer)
– 2 layers of lipids with proteins floating
through it.
• In the "fluid mosaic model" of membrane
structure, the membrane is a fluid bilipid
layer in which protein molecules are either
partially or wholly embedded. These layers
easily move around
Lipids
Rap
Protein
2. Nucleus
– Only in Eukaryotic cells.
– *Stores
hereditary information.
Nuclear
Membrane
– Surrounded by Chromatin
a double nuclear membrane
or envelope w/ pores
– Chromatin (strands of a combination of
DNA and protein within nucleus. These will
later become Chromosomes.
– Nucleolus (1 or >) produces ribosomes
Nucleolus
3. Cytoplasm – “cell’s liquid”
- Made of a gelatinous fluid (Cytosol)
between the nucleus and cell
membrane
Cyclosis – streaming movement of
the cytoplasm.
*Suspends organelles in place and
carries material in solution around
cell
4. Cytoskeleton
- Network of protein
strands that provide
support and mobility
of organelles in
cytoplasm.
- 2 components of
cytoskeleton Microfilaments and
Microtubules (both
made of protein)
5. Mitochondria
- *Powerhouse of the cells.
- Changes chemical bond energy of glucose into a
usable form
- *Site of Cellular respiration
- Contains Cristae or folds to increase surface area
- Has its own DNA and ribosomes and can replicate!
- Found in greater numbers in cells such as muscle
cells & liver cells (2500/cell)
Cristae
Double
Membrane
6. Ribosomes
– Most numerous organelle.
*Site of protein synthesis.
Made up of RNA and protein.
May be free floating in cytoplasm or
attached on Endoplasmic Reticulum
7. Endoplasmic Reticulum
– Channels or passageways in the cell.
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There are two types of ER:
1 – Rough w/ ribosomes attached for
production & distribution of proteins.
2 – Smooth – Synthesis of lipids &
detoxification of toxins
8. Golgi Apparatus (Bodies)
– Stack of smooth flat sacs
- Modifies, collects, packages &
distributes molecules to all
parts of a cell
9. Lysosomes
- *Produces digestive enzymes
– Are the cells' garbage disposal system.
They breakdown worn out organelles
– Clean up dead cells
– Responsible for the un-webbing of hands
of fetus while developing in utero
– These are rare in plant cells
10. Vacuoles
- *Stores food, water and wastes
- Plant cells have a very large central water
vacuole for support (turgor)
- Animal cells have many small vacuoles
11. Centrioles
– Found in animal cells 2
perpendicular bundles of
microtubules
- Function during cell division
Plant Cells’ Unique structures
Plastids
–Store starch or fats and many contain pigments to
absorb light.
- Chloroplasts - Double membraned.
Contain Chlorophyll and DNA
Convert solar energy into chemical bond energy of
glucose (Photosynthesis)
Amyloplasts (Leucoplasts)
Store starch
Cell Wall
– Gives cell rigidity, support and protection.
- Made up of cellulose with pectin (glue)
between adjacent cells.
1. Nucleus
2. Ribosomes
3. Mitochondria
4. Chloroplasts
5. Cell Membrane
6. Cytoplasm
7. Cell Wall
8. Central Vacuole
9. Golgi Apparatus
10.Endoplasmic
Reticulum
Typical Plant Cell
Cheek
Cells
Nucleus
Cytoplasm
Cell Membrane
Cyclosis
Elodea
Onion Cells
Amyloplast
Cell Wall
Potato Cells
1. _______________
2. _______________
3. _______________ (Dots)
4. _______________
5. _______________
6. _______________
7. _______________
8. _______________
9. _______________
10._______________
11._______________
12._______________
13._______________
Typical Animal Cell
1. Nucleolus
2. Nucleus
3. Ribosome
4. Vacuole
5. Rough ER
6. Golgi Apparatus
7. Microtubule
8. Smooth ER
9. Mitochondria
10. Vacuole
11. Cytoplasm
Typical Animal Cell
12. Lysosome
13. Centriole
Organelle
Function
Plant Cells
Animal Cells
Mitochondria
Site of cellular respiration - transfer of energy - Folds
called Cristae
Yes
Yes
Ribosomes
Site of Protein synthesis
Yes
Yes
Endoplasmic Reticulum
Rough - Protein packaging & transport site
Smooth - Sythesis of lipids
Yes
Yes
Golgi Apparatus
Processing & packaging center for cell secretions
Few
Many
Lysosomes
Produce hydrolytic enzymes
Few
Many
Cytoskeleton
Network of protein filaments - keep cell's shape and for
movement
Yes
Yes
Microfilaments &
microtubules
Support, movement and cell division
Yes
Yes
Cilia & Flagella
Cell movement & circulation Cilia - many & short,
Flagella - 1or 2 & long
Yes
Yes
Nucleolus
Production of ribosomes
Yes
Yes
Nucleus
Contains DNA, synthesizes RNA & Ribosomes
Yes
Yes
Chromatin
DNA & protein - genetic information
Yes
Yes
Cell Wall
Outmost layer of plant cell - support & protection Made
of cellulose & pectin glue between walls
Yes
No
Vacuole
Stores enzymes, wastes, water & food Large water in
plants - support
Yes, large
water
vacuole
Many
Yes
No
No
Yes
Yes
Yes
Plastid
Centrioles
Cell Membrane
Stores food and pigments - Chloroplasts
(photosynthesis) & leucoplasts (stores starch)
Microtubules that function during cell division
Selectively permeable - made of a bilipid layer &