1. Cell Structure & Function
Chapter 6.2+
Cellular Biology

2. What you need to know!
The differences between prokaryotic and eukaryotic cells.
The structure and function of organelles common to plant and animal cells.
The structure and function of organelles found only in plant cells or only in animal cells.
How chloroplasts and mitochondria evolved through endosymbiosis (Endosymbiotic Theory)

3. Cell Size Surface Area (SA) – How a cell gets what it needs
Volume – Size of the cell (cytoplasm)
SA/V ratio = survivability (the higher the number, the better)

4. Prokaryotes vs. Eukaryotes

5. Prokaryotes vs. Eukaryotes
Prokaryotes Eukaryotes
Bacteria Animal cells, plant cells,
fungi, protists
Single celled Mostly multi-cellular
No membrane membrane bound
bound organelles organelles
Very small 100x bigger
4 byo 3 byo (Endosymbiotic
Theory)
Naked DNA (nucleoid) Chromatin

6. Both have: Plasma membrane Cytoplasm DNA Ribosomes
This is the minimum requirement for living cells

7. Cell organelles vs cell structures
Definition: A true organelle is surrounded by one or more membranes
Single membrane bound organelles:
Golgi ER
Vacuole
Lysosome, Peroxisomes
Cilia, Flagella

8. Cell organelles vs cell structures
Double membrane bound organelles:
Nucleus (N)
Mitochondria (M)
Chloroplasts (C)

9. Endosymbiotic Theory
M & C were prokaryotic organisms that were swallowed by another larger prokaryote 3-4 byo via phagocytosis
Host cell failed to digest M & C and ultimately formed a: mutualistic symbiosis with their host.

10. Endosymbiotic Theory Arguments that support ET
M & C have independent DNA
M & C DNA is similar to prokaryotic DNA
M & C multiply independently from the rest of the cell
M & C have double membranes

11. Cell structures that are not real organelles
Ribosomes
Membranes
Plasms
Centrioles
Cytoskeleton

12. Cytoskeleton Network of elastic fibers Made of proteins
Found in eukaryotes
Used for cell shape, movement, anchoring and movement of organelles, mitosis
Microfilaments
Intermediate Filaments
Microtubules

13. Cytoskeleton
Microfilaments
Intermediate
Filaments
Microtubule
Size
small
medium
large
Protein
subunits
actin
keratin
tubulin
Functions
Muscle contrac-
tion,
Makes cyto-
plasm gel-like,
amoeba
movement
Permanent role
in cytoskeleton
nucleus anchor
Grow out of centrosome
Easy assembly/
Disassembly
Attachment of
Organelles
Sliding tracks
For organelles
Separate
Chromosomes in
Mitosis
Cilia and
Flagella

14. Endomembrane System
Large membrane system that spans entire cell, makes up for over 50% of cell’s entire membrane, used for transport, secretion, compartmentalization: nuclear envelope, ER, Golgi, lysosomes, vesicles (membrane bound, liquid filled spheres)
Directly connected through touching membranes: nuclear envelope and ER
Indirectly connected through migrating vesicles: ER with Golgi, Golgi with Plasma Membrane

15. Secretion of Proteins Example
pancreas  insulin
Rough ER (rER) - ribosomes on rER make polypeptide chains that grow inside the lumen (space inside ER)

16. Secretion of Proteins
Vesicles from rER pinch off, migrate to and fuse with Golgi, forming side (cis)
Golgi – finishes proteins
Packed into vesicles pinching off the maturing side (trans)
Vesicles migrate and fuse with plasma membrane
exocytosis

17. Secretion of Lipids
Smooth ER: produces lipids for milk secretion, sex/steroid hormones, cholesterol
Vesicle pinches off products and migrates to the cell membrane

18. The Inner Life of the Cell