There are two main types of cells - prokaryotic and eukaryotic cells. Prokaryotic cells like bacteria do not have a nucleus or membrane-bound organelles. Eukaryotic cells have a nucleus enclosed in a nuclear envelope and membrane-bound organelles like the mitochondria and chloroplasts. Mitochondria and chloroplasts were originally free-living bacteria that were engulfed by early eukaryotic cells in a process called endosymbiosis, providing both cells with evolutionary advantages. Eukaryotic cells have complex internal structures like the nucleus, endoplasmic reticulum, Golgi apparatus and lysosomes that allow them to produce proteins, package and transport materials within the cell.

1. Regents Biology
Cells: Two main types

2. before
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nucleus
true
nucleus

3. Regents Biology
Prokaryotes
1. NO nucleus
1. unicellular
1. NO membrane-bound organelles
(just ribosomes)
2. Forerunner to eukaryotic cells
(smaller, simpler)
3. DNA – single strand and circular
-Bacteria, archaea
4. 70S Ribosomes

4. Eukaryotes
1.Has a nucleus with a nuclear
envelope
2. Bigger and more complex than
prokaryotes
3.Have membrane bound organelles
4.DNA – double-stranded and forms
chromosomes (highly organized)
5. Uni- OR multicellular organisms
animals, plants, fungi…
6. 80S Ribosomes
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5. Similarities
1. Contain all four biomolecules
(lipids, carbs, proteins, and nucleic acids)
1. Have ribosomes (eukaryotes 80S,
prokaryotes 70S)
2. Have DNA
3. Similar Metabolism
4. Can be unicellular
5. Have cell/plasma membranes or cell wall
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6. Evolution of Eukaryotic Cells
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7. Organelles
 Organelles do the work of cells
 each structure has a job
 keeps the cell alive; keeps you alive
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Model Animal Cell

8. Cytoplasm
jelly-like material holding
organelles in place
cell membrane
cell boundary
controls movement
of materials in & out
recognizes Regents Biology
signals

9. Cell membrane
 Function
 Barrier
 Control
 O2,CO2, food, H2O, nutrients, waste
 Communication
 between cells
 Structure
 phospholipid bilayer
 receptor molecules
 proteins
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phosphate
“head”
lipid “tail”

10. Vesicles  Function
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 Transport
 Endocytosis
 Exocytosis
 Structure
 membrane sac
large food
particle
vesicle
Proteins etc
Endocytosis!
Exocytosis!

11. Vacuoles: Storage
plant cells
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contractile
vacuole
animal cells
central vacuole
food vacuoles

12. cytoplasm
jelly-like material holding
organelles in place
vacuole & vesicles
storage
transport
cell membrane
cell boundary
controls movement
of materials in & out
recognizes Regents Biology
signals

13. Lysosomes
 Function
 little “stomach” of the cell
 digests macromolecules
 “clean up crew” of the cell
 cleans up broken down
organelles
 Structure
 vesicles of digestive
enzymes
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only in
animal cells
synthesized by rER,
transferred to Golgi
Where
old organelles
go to die!
 lyso– = break apart
 –some = body

14. Lysosomes
white blood cells attack
& destroy invaders =
digest them in
lysosomes
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1960 | 1974
1974 Nobel prize: Christian de Duve
Lysosomes discovery in 1960s

15. When things go bad…
 Diseases of lysosomes are often fatal
 digestive enzyme not working in lysosome
 picks up biomolecules, but can’t digest one
 lysosomes fill up with undigested material
 grow larger & larger until disrupts cell & organ
function
 lysosomal storage diseases
 more than 40 known diseases
 example:
Tay-Sachs disease
build up undigested fat
in brain cells
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16. But sometimes cells need to die…
 Lysosomes can be used to kill cells when
they are supposed to be destroyed
 some cells have to die for proper
development in an organism
 apoptosis
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 “auto-destruct” process
 lysosomes break open & kill cell
 ex: tadpole tail gets re-absorbed
when it turns into a frog
 ex: loss of webbing between your
fingers during fetal development

17. Fetal development
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15 weeks
6 weeks
syndactyly

18. Apoptosis
 programmed destruction of cells in multi-cellular
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organisms
 programmed development
 control of cell growth
 example:
if cell grows uncontrollably this self-destruct
mechanism is triggered to remove damaged cell
 cancer must over-ride this to enable tumor
growth

19. Regents Biology

20. cytoplasm
 jelly-like material holding
organelles in place
vacuole & vesicles
transport
storage
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lysosome
food digestion
garbage disposal &
recycling
cell membrane
cell boundary
controls movement
of materials in & out
recognizes signals

21. Making Energy
 Cells must convert incoming energy to
forms that they can use for work
 mitochondria:
from glucose to ATP
 chloroplasts:
from sunlight to ATP & carbohydrates
 ATP = active energy
 carbohydrates = stored energy
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+
ATP
ATP

22. Mitochondria & Chloroplasts
 Important to see the similarities
 transform energy
 generate ATP
 double membranes = 2 membranes
 semi-autonomous organelles
 move, change shape, divide
 internal ribosomes, DNA & enzymes
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23. Mitochondria
 Function
 make ATP energy from cellular respiration
 sugar + O2  ATP
 fuels the work of life
 Structure
 double membrane
in both animal &
plant cells
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ATP

24. cytoplasm
 jelly-like material holding
organelles in place
vacuole & vesicles
transport inside cells
storage
mitochondria
make ATP energy
from sugar + O2
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lysosome
food digestion
garbage disposal &
recycling
cell membrane
cell boundary
controls movement
of materials in & out
recognizes signals

25. Plants make energy two ways!
 Mitochondria
 make energy + O2 from sugar
 cellular respiration
 sugar + O2  ATP
 Chloroplasts
 make energy + sugar from sunlight
 photosynthesis
 sunlight + CO2  ATP & sugar
 ATP = active energy
 sugar = stored energy
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 build leaves & roots & fruit
out of the sugars
ATP
sugar
ATP

26. Mitochondria
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27. Dividing Mitochondria
Who else divides
like that?
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What does this tell us about
the evolution of eukaryotes?

28. Mitochondria
 Almost all eukaryotic cells have mitochondria
 there may be 1 very large mitochondrion or
100s to 1000s of individual mitochondria
 number of mitochondria is correlated with
aerobic metabolic activity
 more activity = more energy
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needed = more mitochondria
What cells would
have a lot of
mitochondria?
active cells:
• muscle cells
• nerve cells

29. Mitochondria are in both cells!!
animal cells plant cells
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mitochondria
chloroplast

30. Chloroplasts
 Function
 photosynthesis
 generate ATP & synthesize sugars
 transform solar energy into chemical energy
 produce sugars from CO2 & H2O
 Semi-autonomous
 moving, changing shape & dividing
 can reproduce by pinching in two
Who else divides
like that?
bacteria!
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31. Regents Biology

32. Endosymbiosis theory
 Mitochondria & chloroplasts were once
free living bacteria
 engulfed by ancestral eukaryote
 Endosymbiont
 cell that lives within another cell (host)
 as a partnership
 evolutionary advantage
for both
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 one supplies energy
 the other supplies raw materials
& protection
Lynn Margulis
U of M, Amherst
1981 | ??

33. Endosymbiosis theory
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Evolution of eukaryotes

34. Endosymbiosis
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Evidence
• Mitochondrial has its own DNA
• Mitochondrial DNA more
similar to bacterial DNA than nuclear DNA of
cell
• Mitochondria divide by binary fission, not
mitosis

35. Regents Biology
central vacuole
storage: food,
water or waste
mitochondria
make ATP in
cellular respiration
cell wall
support
chloroplast
make ATP & sugars in
photosynthesis
cell membrane
cell boundary
controls movement
of materials in & out
recognizes signals
lysosome
digestion & clean up
cytoplasm

36. Cells need workers (proteins)!
 Making proteins
 to run daily life & growth, the cell must…
 read genes (DNA)
 build proteins
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 structural proteins (muscle fibers, hair, skin, claws)
 enzymes (speed up chemical reactions)
 signals (hormones) & receptors
 organelles that do this work…
 nucleus
 ribosomes
 endoplasmic reticulum (ER)
 Golgi apparatus

37. Proteins do all the work!
one of the major job of cells is to make proteins,
because…
structure
enzymes
DNA proteins cells
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proteins do all the work!
signals
receptors

38. Nucleus
 Function
 control center of cell
 protects DNA
 instructions for building proteins
 Structure
 nuclear membrane
 nucleolus
 ribosome factory
 chromosomes
 DNA
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39. Regents Biology
Ribosomes on ER
Ribosomes
 Function
 protein factories
 Eukaryotes have 80S, prokaryotes 70S
 read instructions to build proteins from DNA
 Structure
 2 subunits
 some free in cytoplasm
 some attached to ER
large
subunit
small
subunit

40. Endoplasmic Reticulum
 Function
 part of protein factory
 helps complete the
proteins
 makes membranes
 Structure
 rough ER
 ribosomes attached
 works on proteins
 smooth ER
 makes membranes
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41. cytoplasm
jelly-like material holding
organelles in place
vacuole & vesicles
transport inside cells
storage
mitochondria
make ATP energy
from sugar + O2
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lysosome
food digestion
garbage disposal &
recycling
cell membrane
cell boundary
controls movement
of materials in & out
recognizes signals
nucleus
protects DNA
controls cell
ribosomes
builds proteins
ER
helps finish proteins
makes membranes

42.  finishes, sorts, labels & ships proteins
vesicles
carrying proteins
Golgi Apparatus
 Function
 like UPS headquarters
 shipping & receiving department
 ships proteins in vesicles
 “UPS trucks”
 Structure
 membrane sacs
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43. cytoplasm
jelly-like material holding
organelles in place
vacuole & vesicles
transport inside cells
storage
mitochondria
make ATP energy
from sugar + O2
cell membrane
cell boundary
controls movement
of materials in & out
recognizes Regents Biology
signals
nucleus
protects DNA
controls cell
ribosomes
builds proteins
lysosome
food digestion
garbage disposal &
recycling
ER
helps finish proteins
makes membranes
Golgi apparatus
finishes, packages
& ships proteins

44. nucleus
control cell
protects DNA
Golgi apparatus
finish & ship
proteins
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central vacuole
storage: food,
water or waste
mitochondria
make ATP in
cellular respiration
cell wall
support
chloroplast
make ATP & sugars in
photosynthesis
cell membrane
cell boundary
controls movement
of materials in & out
recognizes signals
endoplasmic reticulum
processes proteins
makes membranes
lysosome
digestion & clean up
cytoplasm
ribosomes
make proteins