Download Cell Structure and Function

Cell Structure and
Function
Textbook: Chapter 6
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)
1. Prokaryotes vs. Eukaryotes
1. Prokaryotes vs. Eukaryotes
Prokaryotes
Bacteria
Single celled
Eukaryotes
Animal cells, plant cells,
fungi, protists
Mostly multi-cellular
No membrane
bound organelles
membrane bound
organelles
Very small
100x bigger
4 byo
3 byo (Endosymbiotic
Theory)
Chromatin
Naked DNA
Both have:
• Plasma membrane
• Cytoplasm
• DNA
• Ribosomes
This is the minimum requirement for living
cells
2. 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
2. Cell organelles vs cell
structures
Double membrane bound organelles:
• Nucleus (N)
• Mitochondria (M)
• Chloroplasts (C)
Endosymbiotic Theory
States that M & C were prokaryotic
organisms that were swallowed by another
larger prokaryote 3-4 byo through a
process called endocytosis. M & C were
not digested but formed a: mutualistic
symbiosis with their host.
Endosymbiotic Theory
Arguments that support ET
1. M, C, and N have their own DNA
2. M and C DNA is similar to prokaryotic
DNA
3. M and C multiply independent from
nucleus/mitosis
4. M, C, and N have double membranes
Cell structures that are not real
organelles
•
•
•
•
•
Ribosomes
Membranes
Plasms
Centrioles
Cytoskeleton
3. Cytoskeleton
•
•
•
•
Network of elastic fibers
Made of proteins
Found in eukaryotes
Used for cell shape, movement, anchoring
and movement of organelles, mitosis
Microfilaments
3. Cytoskeleton
Intermediate Filament
Microtubule
Microfilaments
Intermediate
Filaments
Microtubule
Size
small
medium
large
Protein
subunits
actin
keratin
tubulin
Characteristics
Tension
resistant
Tension
resistant
Compression
resistant
Functions
Muscle contraction,
Makes cytoplasm 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
4. 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)
a) Directly connected through touching
membranes: nuclear envelope and ER
b) Indirectly connected through migrating
vesicles: ER with Golgi, Golgi with
Plasma Membrane
Secretion of Proteins
• Examples: mammary cells  milk,
pancreas  insulin
• Rough ER (rER) - ribosomes on rER make
polypeptide chains that grow inside lumen
(space inside ER)
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
Secretion of Lipids
• Smooth ER: lipids for milk secretion,
sex/steroid hormones, cholesterol
Inner workings of the cell
• http://www.youtube.com/watch?v=zrXykvo
rybo&feature=player_embedded