Transcript Eukaryotic Cells

A Tour of the Cell
Read pg.98-99 ~ Create a double bubble to compare
and contrast prokaryotic and eukaryotic cells
Prok
aryo
tic
DIFFERENCES
Eukaryotic
SIMILARITIES
DIFFERENCES
Chp.6:
Tour of the Cell
How big is a cell?
• Cells Alive! How Big is a Cell?
• Most cells are between 1 and 100 μm (10-6
or 1/ 1,000,000 m)
• Eukaryotic Cells are larger than
prokaryotic cells
Types of cells
Prokaryote
bacteria cells
- no organelles
- organelles
Eukaryote
animal cells
Eukaryote
plant cells
Prokaryotic Cells
• No nucleus, no membrane-bound
organelles
• But, they do have a cell membrane and
they do have an organelle
– Ribosomes!
• Also have Nucleoid region, Cell Wall, and
Cytosol (fluid)
Eukaryotic Cells
• Eukaryotic Cells contain a nucleus and
membrane-bound organelles
• The membrane is key!
Limits to Cell Size
• As a cell grows, its surface area
to volume ratio decreases
• This means the cell has more
volume that needs to get
oxygen, food, get rid of waste
but less SA to do it over (in
proportion)
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
Golgi
– unique combinations of lipids & proteins
– embedded enzymes & reaction centers
• chloroplasts & mitochondria
ER
Cells gotta work to live!
• What jobs do cells have to do?
– Make proteins
• proteins control every
cell function
– Store energy
• for daily life
• for growth
– Make more cells
• growth
• repair
• renewal
Proteins do all the work!
proteins
cells
DNA
organism
Repeat after me…
Proteins do all the work!
Cell functions
• Building proteins
1. read DNA instructions
2. build proteins
3. process proteins
• folding
• modifying
– removing amino acids
– adding other molecules
» e.g, making glycoproteins
for cell membrane
4. 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
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
large
subunit
• Function
– protein production
small
subunit
• Structure
– rRNA & protein
– 2 subunits combine
0.08mm
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
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
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
• 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
protein
on its way!
endoplasmic
reticulum
nucleus
DNA
TO:
RNA
vesicle
TO:
TO:
vesicle
ribosomes
TO:
finished
protein
protein
Making Proteins
Golgi
apparatus
Putting it together…
nucleus
nuclear pore
Making proteins
cell
membrane
protein secreted
rough ER
ribosome
vesicle
proteins
smooth ER
transport
vesicle
cytoplasm
Golgi
apparatus
Lysosomes
•Sac of hydrolytic enzymes; intracellular digestion
of macromolecules
• Phagocytosis
• Autophagy: recycle cell’s own organic material
• Apoptosis: programmed cell death
Vacuoles
• Membrane-bound sacs
– digestion & release of
cellular waste
– Food (phagocytosis)
– Contractile (pump
excess water)
– Central (storage in
plants)
Mitochondria
• Quantity in cell correlated
with metabolic activity
– cellular respiration
• double membrane
(phospholipid);
– Outer membrane is smooth
– Inner membrane is highly
convoluted forming folds
called cristae
• Contains enzymes used for
ATP production
•contain own DNA
Chloroplast
• Contains chlorophyll, captures energy from Sun and
converts it to chemical bond energy via photosynthesis
• Structure: double membrane, contains thylakoids
(flattened disks), grana (stacked thylakoids), stroma.
• own DNA
Microscope Review
Types of Microscopes
• Compound Light Microscopes (like what we use in
class)-uses 2 or more lenses to magnify objects.
– Max magnification 1500X.
• Electron Microscopes-uses a beam of electrons to
image a specimen.
Scanning EM(SEM)
– Surface
– Magnification 60,000X
Transmission EM(TEM)
– Inside
– Magnification 100,000 X +
Body Tube
Eyepiece
Revolving
Nosepiece
Low Power
Objective
Arm
Medium Power
Objective
Stage Clip
High Power
Objective
Course Adjustment
Knob
Stage
Fine Adjustment
Knob
Diaphragm
Light Source
Base
Using a Microscope
• Always carry the microscope by the arm and the base.
• To calculate magnification, multiply the eyepiece
magnification by the objective magnification.
• Always make sure the stage is all the way up when focusing
and slowly bring the stage down.
• When on low power, use the course adjustment knob (the
big knob)
• When on medium and high power, use the fine adjustment
knob (the little knob) ONLY!!!
• NEVER use the course adjustment knob on medium or high
power!!! Why? You are so close to the slide that you will
run into it with the objective!!
• When you are finished with the microscope, wrap the cord
around the base and put the lowest objective down. Make
sure the stage is all the way down.
How to Draw a Diagram from a
Microscope
Drawing the Diagram
1. If it is not already provided, draw your “field of view”
•
2.
•
3.
This is the circle that you see when you look through the
microscope
Draw exactly what you see
make sure it’s not a water spot or air bubble!!!
Add color exactly like the colors you observe in the
specimen.
4.
Mark the diagram with the specimen name and
magnification.
Labels
5. Printed neatly
6. Horizontal to the upper edge of the paper
7. Lines connecting labels to the diagram should be
straight.
Pseudopod
Food vacuole
Ameoba
400X
Assignment
• Cell Observations: Prokaryotic vs.
Eukaryotic Cells
– Examine at least one of each of the following
types of cells
•
•
•
•
Bacteria
Protist
Plant
Animal
– Draw your observations under high power
– Complete analysis questions on the back