1. Tour of the Cell 1

2. Cells gotta work to live!
What jobs do cells have to do?
Build proteins
proteins control every cell function
Utilize energy
for daily life
for growth
Make new cells
growth
repair
renewal
Maintain Homeostasis
Digestion/Waste Removal

3. Building Proteins

4. Cells need workers = proteins!
Building proteins
read genes (DNA) instructions
build proteins
process proteins
folding
modifying
removing amino acids
adding other molecules
e.g, making glycoproteins for cell membrane
address & transport proteins

5. Proteins do all the work!
Structural (muscle fibers, hair, skin, claws)
Enzymes (speed up chemical rxns)
Signals (hormones) & Receptors
proteins
cells
DNA
organism

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

7. What kind of molecules need to pass through?
histone protein
chromosome
DNA
Nucleus
Function
Control center of cell
Contains & protects
chromosomes (DNA)
Instructions for building proteins
Structure
nuclear envelope
double membrane
membrane fused in spots to create pores
allows large macromolecules to pass through
nuclear
pores
pore
nuclear envelope
nucleolus
What kind of molecules need to pass through?

8. 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

10. 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

11. “UNIVERSAL STRUCTURES”
small
subunit
large
“UNIVERSAL STRUCTURES”
Ribosomes
Function
site of protein synthesis (translation)
read instructions to build proteins from DNA
Structure
rRNA (ribosomal RNA) & 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.

12. 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

13. Endoplasmic Reticulum
Function - many functions…
processes proteins - helps complete the proteins after ribosome builds them
manufactures membranes
synthesis & hydrolysis of many compounds
Structure
membrane connected to nuclear envelope & extends throughout cell
rough ER (ribosomes attached) and smooth ER
accounts for 50% membranes in eukaryotic cell

14. Types of ER
rough
smooth

15. Smooth ER function Many metabolic processes synthesis hydrolysis
synthesize lipids
oils, phospholipids, steroids & sex hormones
hydrolysis
hydrolyze glycogen into glucose
in liver
detoxify drugs & poisons
ex. alcohol & barbiturates
most important

16. Which cells have lot of rough ER?
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?
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))

17. Rough ER function - Membrane Factory
Build new membrane
synthesize phospholipids + membrane proteins
builds membranes
ER membrane expands
bud off & transfer to other parts of cell that need membranes

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

19. Which cells have lots of Golgi?
Golgi Apparatus
Function
finishes, sorts, labels & ships cell products
UPS headquarters - “shipping & receiving department”
ships products in vesicles
“UPS trucks”
Structure
Membrane sacs = “cisternae”
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
Which cells have lots of Golgi?

20. Golgi Apparatus

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

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

23. 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