Transcript Organelle Lecture Day 1

Cell Time
9/17 Outline
• Quick History
• Quick Microscopy
• Organelle Overview –focus on protein
production today
HW: Read and outline Chapter 4
HW: Bozeman Videos 13, 15, 16, 17
Quiz: Organelle Tuesday
• 1665 Robert Hooke Sees cork cells
• 1674 Anton Von Leeuwenhoek sees living cells
with much better microscopes
Not Robert Hooke
Anton Von Leeuwenhoek
Magnification vs. Resolution
• Magnification – ratio of image size to actual
size
• Resolution – measure of clarity
• We stain cells for contrast!
Light vs Electron Microscope
Figure 4.3
50 m
Light Microscopy (LM)
Brightfield
(stained specimen)
Phase-contrast
Differential-interference
contrast (Nomarski)
10 m
50 m
Brightfield
(unstained specimen)
Fluorescence
Confocal
Electron Microscopy (EM)
Longitudinal section
of cilium
Cross section
of cilium
Cilia
Scanning electron
microscopy (SEM)
2 m
2 m
Transmission electron
microscopy (TEM)
Organelle time
• What do ALL cells have?
Organelle time
• What do ALL cells have?
– Plasma membrane
– Semifluid substance called cytosol
– Chromosomes (carry genes)
– Ribosomes (make proteins)
Lets focus on eukaryotes for now
• Why should they use organelles?
Why organelles?
• Specialized structures
– specialized functions
mitochondria
• cilia or flagella for locomotion
• Containers
– partition cell into compartments
– create different local environments
chloroplast
• separate pH, or concentration of materials
– distinct & incompatible functions
• lysosome & its digestive enzymes
• Membranes as sites for chemical reactions
– unique combinations of lipids & proteins
– embedded enzymes & reaction centers
Golgi
• chloroplasts & mitochondria
ER
When we eat spiders, chicken, fish,
or beans what are they high in?
Proteins
Some Functions
• Metabolism (Enzymes)
• Support (Keratin, collagen)
• Transport (Channels, hemoglobin)
Some Functions
•
•
•
•
Defense (Antibodies)
Regulation (Hormones – Insulin)
Motion (Myosin and Actin)
Recognition
Building proteins
– read DNA instructions
– build proteins
– process proteins
• folding
• modifying
– removing amino acids
– adding other molecules
» e.g, making glycoproteins
for cell membrane
– address & transport proteins
Building Proteins
• Organelles involved
– nucleus
– ribosomes
– endoplasmic reticulum
(ER)
– Golgi apparatus
– vesicles
The Protein Assembly Line
nucleus
ribosome
ER
Golgi
apparatus
vesicles
Nucleus DNA
• Function
chromosome
– protects DNA
histone protein
• Structure
– nuclear envelope
• double membrane
• membrane fused in spots to create pores
– allows large macromolecules to pass through
nuclear
pores
What kind of
molecules need to
pass through?
nuclear
pore
nucleolus
nuclear envelope
1
nuclear
membrane
production of mRNA
from DNA in nucleus
DNA
Nucleus
mRNA
2
nuclear pore
mRNA travels from
nucleus to ribosome in
cytoplasm through
nuclear pore
small
ribosomal
subunit
mRNA
large
ribosomal
subunit
cytoplasm
Nucleolus
• Function
– ribosome production
• build ribosome subunits from rRNA & proteins
• exit through nuclear pores to cytoplasm &
combine to form functional ribosomes
large subunit
small
subunit
rRNA &
proteins
ribosome
nucleolus
Ribosomes
• Function
large
subunit
small
subunit
– protein production
• Structure
– rRNA & protein
– 2 subunits combine
0.08m
Ribosomes
Rough
ER
Smooth
ER
Types of Ribosomes
• Free ribosomes
– suspended in cytosol
– synthesize proteins that function in
cytosol
• Bound ribosomes
– attached to endoplasmic reticulum
– synthesize proteins
for export or
for membranes
membrane proteins
Endoplasmic Reticulum
• Function
– processes proteins
– manufactures membranes
– synthesis & hydrolysis of many compounds
• Structure
– membrane connected to nuclear envelope & extends
throughout cell
Types of ER
rough
smooth
Smooth ER function
• Membrane production
• Many metabolic processes
– synthesis
• synthesize lipids
– oils, phospholipids, steroids & sex hormones
– hydrolysis
• hydrolyze glycogen into glucose
– in liver
• detoxify drugs & poisons
– in liver
– ex. alcohol & barbiturates
– Ion Storage
Membrane Factory
• Build new membrane
– synthesize
phospholipids
• builds membranes
– ER membrane expands
• bud off & transfer to
other parts of cell that
need membranes
Rough ER function
• Produce proteins for export out of cell
– protein secreting cells
– packaged into transport vesicles for export
Which cells
have lot of
rough ER?
Synthesizing proteins
cisternal
space
polypeptide
signal
sequence
ribosome
ribosome
mRNA
membrane of
endoplasmic reticulum
cytoplasm
Golgi Apparatus
• Function
– finishes, sorts, tags & ships cell products
• like “UPS shipping department”
– ships products in vesicles
Which cells
have lots
of Golgi?
• membrane sacs
• “UPS trucks”
secretory
vesicles
transport vesicles
Golgi Apparatus
Vesicle transport
protein
vesicle
budding
from rough
ER
ribosome
migrating
transport
vesicle
fusion
of vesicle
with Golgi
apparatus
endoplasmic
reticulum
nucleus
protein
on its way!
DNA
RNA
vesicle
TO:
TO:
TO:
vesicle
ribosomes
TO:
finished
protein
protein
Making Proteins
Golgi
apparatus
Making proteins
Putting it together…
nucleus
nuclear pore
cell
membrane
protein secreted
rough ER
ribosome
vesicle
proteins
smooth ER
transport
vesicle
cytoplasm
Golgi
apparatus