1. A Tour of the Cell

2. Read pg.98-99 ~ Create a double bubble to compare and contrast prokaryotic and eukaryotic cells
DIFFERENCES
DIFFERENCES
SIMILARITIES

3. Chp.6: Tour of the Cell 3

4. 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

5. Prokaryote bacteria cells Eukaryote animal cells
Types of cells
Prokaryote bacteria cells
- no organelles
- organelles
Eukaryote animal cells
Eukaryote plant cells

6. 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)

8. Eukaryotic Cells
Eukaryotic Cells contain a nucleus and membrane-bound organelles
The membrane is key!

9. 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)

10. Why organelles? Specialized structures Containers
mitochondria
Why organelles?
Specialized structures
specialized functions
cilia or flagella for locomotion
Containers
partition cell into compartments
create different local environments
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
chloroplasts & mitochondria
chloroplast
Golgi
Why organelles?
There are several reasons why cells evolved organelles. First, organelles can perform specialized functions. Second, membrane bound organelles can act as containers, separating parts of the cell from other parts of the cell. Third, the membranes of organelles can act as sites for chemical reactions.
Organelles as specialized structures
An example of the first type of organelle is cilia, these short filaments act as "paddles" to help some cells move.
Organelles as Containers
Nothing ever invented by man is as complex as a living cell. At any one time hundreds of incompatible chemical reactions may be occurring in a cell. If the cell contained a uniform mixture of all the chemicals it would not be able to survive. Organelles surrounded by membranes act as individual compartments for these chemical reactions. An example of the second type of organelle is the lysosome. This structure contains digestive enzymes, these enzymes if allowed to float free in the cell would kill it.
Organelle membranes as sites for chemical reactions
An example of the third type of organelle is the chloroplast. The molecules that conduct the light reactions of photosynthesis are found embedded in the membranes of the chloroplast. ER 10

11. 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 11

12. Proteins do all the work!
DNA
cells
Repeat after me…
Proteins do all the work!
organism

13. 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

14. Building Proteins Organelles involved nucleus ribosomes
endoplasmic reticulum (ER)
Golgi apparatus
vesicles
The Protein Assembly Line
Golgi apparatus
nucleus
ribosome ER
vesicles

15. Nucleus Function Structure protects DNA nuclear envelope
histone protein
chromosome
DNA
Function
protects DNA
Structure
nuclear envelope
double membrane
membrane fused in spots to create pores
allows large macromolecules to pass through
nuclear
pores
pore
nuclear envelope
nucleolus 15

16. production of mRNA from DNA in nucleus
nuclear
membrane 1
production of mRNA from DNA in nucleus
small
ribosomal
subunit
large
cytoplasm
mRNA
nuclear pore 2
mRNA travels from nucleus to ribosome in cytoplasm through nuclear pore 16

17. 17

18. Nucleolus Function ribosome production
build ribosome subunits from rRNA & proteins
exit through nuclear pores to cytoplasm & combine to form functional ribosomes
small
subunit
large subunit
ribosome
rRNA &
proteins
nucleolus 18

19. Ribosomes Function Structure protein production rRNA & protein
small
subunit
large
Function
protein production
Structure
rRNA & protein
2 subunits combine
0.08mm
Ribosomes
Rough ER
Smooth
The genes for rRNA have the greatest commonality among all living things. There is very little difference in the DNA sequence of the rRNA genes in a humans vs. a bacteria.
Means that this function (building of a ribosome) is so integral to life that every cell does it almost exactly the same way.
Change a base and this changes the structure of the RNA which causes it to not function. 19

20. Types of Ribosomes Free ribosomes Bound 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 20

21. Endoplasmic Reticulum
Function
processes proteins
manufactures membranes
synthesis & hydrolysis of many compounds
Structure
membrane connected to nuclear envelope & extends throughout cell
accounts for 50% membranes in eukaryotic cell 21

22. Types of ER
rough
smooth 22

23. 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
ex. alcohol & barbiturates 23

24. Membrane Factory Build new membrane synthesize phospholipids
builds membranes
ER membrane expands
bud off & transfer to other parts of cell that need membranes 24

25. Rough ER function Produce proteins for export out of cell
protein secreting cells
packaged into transport vesicles for export
Which cells have a lot of ER?
protein production cells like pancreas = production of digestive enzymes (rough endoplasmic reticulum from a cell of exocrine pancreas (88000X)) 25

26. Synthesizing proteins
cytoplasm
cisternal
space
mRNA
ribosome
membrane of
endoplasmic reticulum
polypeptide
signal
sequence
ribosome

27. Golgi Apparatus Function finishes, sorts, tags & ships cell products
like “UPS shipping department”
ships products in vesicles
membrane sacs
“UPS trucks”
transport vesicles
secretory
vesicles
Cells specialized for secretion?
endocrine glands: produce hormones
pituitary, pancreas, adrenal, testes, ovaries
exocrine glands: produce digestive enzymes & other products
pancreas, mammary glands, sweat glands 27

28. Golgi Apparatus

29. Vesicle transport vesicle budding from rough ER fusion of vesicle
with Golgi
apparatus
migrating
transport
protein
ribosome

30. endoplasmic reticulum
protein on its way!
nucleus
DNA
TO:
RNA
vesicle
TO:
TO:
vesicle
ribosomes
TO:
protein
finished protein
Golgi apparatus
Making Proteins 30

31. Making proteins Putting it together… cytoplasm nucleus cell membrane
transport
vesicle
Golgi
apparatus
smooth ER
rough ER
nuclear pore
nucleus
ribosome
cell
membrane
protein secreted
cytoplasm 31

32. Lysosomes
•Sac of hydrolytic enzymes; intracellular digestion of macromolecules
Phagocytosis
Autophagy: recycle cell’s own organic material
Apoptosis: programmed cell death

33. Vacuoles Membrane-bound sacs digestion & release of cellular waste
Food (phagocytosis)
Contractile (pump excess water)
Central (storage in plants)

34. 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

35. 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

36. Microscope Review

37. 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 +

38. 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

39. 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.

40. How to Draw a Diagram from a Microscope
Drawing the Diagram
If it is not already provided, draw your “field of view”
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.
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.

41. Pseudopod
Food vacuole
Ameoba X

42. 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