1. Tour of the Cell 1

2. 10 m 1 m 0.1 m 1 cm 1 mm 100 mm 10 mm 1 mm 100 nm 10 nm 1 nm 0.1 nm
Figure 4.2
10 m
Human height
1 m
Length of some
nerve and
muscle cells
0.1 m
Chicken egg
Unaided eye
1 cm
Frog egg
1 mm
Human egg
100 mm
Most plant and
animal cells LM
10 mm
Nucleus
Most bacteria
1 mm
Mitochondrion EM
Figure 4.2 The size range of cells
100 nm
Smallest bacteria
Super-
resolution
microscopy
Viruses
Ribosomes
10 nm
Proteins
Lipids
1 nm
Small molecules
0.1 nm
Atoms
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3. Light Microscopy (LM) Electron Microscopy (EM)
Figure 4.3
Light Microscopy (LM)
50 mm
Brightfield
(unstained specimen)
Brightfield
(stained specimen)
Phase-contrast
Differential-interference
contrast (Nomarski)
50 mm
10 mm
Fluorescence
Confocal (without
technique)
Confocal (with technique)
Electron Microscopy (EM)
Longitudinal section
of cilium
Cross section
of cilium
Figure 4.3 Exploring microscopy
Cilia
2 mm
Scanning electron
microscopy (SEM)
Transmission electron
microscopy (TEM)
2 mm
© 2016 Pearson Education, Inc.

4. © 2016 Pearson Education, Inc.
Cell Fractionation
Cell fractionation breaks up cells and separates the components, using centrifugation
Cell components separate based on their relative size
Cell fractionation enables scientists to determine the functions of organelles
Biochemistry and cytology help correlate cell function with structure
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5. Comparing Prokaryotic and Eukaryotic Cells
Basic features of all cells
Plasma membrane
Semifluid substance called cytosol
Chromosomes (carry genes)
Ribosomes (make proteins)
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6. Prokaryote bacteria cells Eukaryote animal cells
Types of cells
- no organelles
- organelles
Eukaryote animal cells
Eukaryote plant cells

7. Metabolic requirements set upper limits on the size of cells
The ratio of surface area to volume of a cell is critical
As the surface area increases by a factor of n2, the volume increases by a factor of n3
Small cells have a greater surface area relative to volume
© 2016 Pearson Education, Inc. 7

8. Surface area increases while total volume remains constant 1 1
Figure 4.6
Surface area increases while
total volume remains constant 5 1 1
Total surface area
[sum of the surface areas
(height ✕ width) of all box
sides ✕ number of boxes] 6
150
750
Total volume
[height ✕ width ✕ length
✕ number of boxes]
Figure 4.6 Geometric relationships between surface area and volume 1
125
125 6
1.2 6
© 2016 Pearson Education, Inc.

9. Animation: Tour of an Animal Cell
© 2016 Pearson Education, Inc.

10. Animation: Tour of a Plant Cell
© 2016 Pearson Education, Inc.

11. Why organelles? mitochondria chloroplast Golgi ER
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

12. Cells gotta work to live!
What jobs do cells have to do?
make proteins
proteins control every cell function
make energy
for daily life
for growth
make more cells
growth
repair
renewal

13. Building Proteins

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

15. Cells functions 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

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

17. What kind of molecules need to pass through?
histone protein
chromosome
DNA
Nucleus
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
What kind of molecules need to pass through?

18. 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

20. 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

21. Ribosomes Function Structure protein production rRNA & protein
small
subunit
large
Ribosomes
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.

22. 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

23. 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

24. Types of ER
rough
smooth

25. 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

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

27. 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))

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

29. Which cells have lots of Golgi?
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
Which cells have lots of Golgi?
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

30. Golgi Apparatus

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

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

33. 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

36. Any Questions!!