eykaryotes
DESCRIPTION
cellsTRANSCRIPT
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Cells: Two main types
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before nucleus
true nucleus
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Prokaryotes1. NO nucleus
2. unicellular
3. NO membrane-bound organelles (just ribosomes)
4. Forerunner to eukaryotic cells (smaller, simpler)
5. DNA – single strand and circular-Bacteria, archaea4. 70S Ribosomes
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Eukaryotes1.Has a nucleus with a nuclear
envelope2.Bigger and more complex than
prokaryotes3.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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Similarities1. Contain all four biomolecules
(lipids, carbs, proteins, and nucleic acids)
2. Have ribosomes (eukaryotes 80S, prokaryotes 70S)
3. Have DNA
4. Similar Metabolism
5. Can be unicellular
6. Have cell/plasma membranes or cell wall
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Evolution of Eukaryotic Cells
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Organelles Organelles do the work of cells
each structure has a job keeps the cell alive; keeps you alive
Model Animal Cell
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cell membranecell boundarycontrols movementof materials in & out
recognizes signals
Cytoplasmjelly-like material holding
organelles in place
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Cell membrane Function
Barrier Control
O2,CO2, food, H2O, nutrients, waste Communication
between cells
Structure phospholipid bilayer receptor molecules
proteins
lipid “tail”
phosphate“head”
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Vesicles Function Transport Endocytosis Exocytosis
Structure membrane sac
large foodparticle
vesicle
Proteins etc
Endocytosis!
Exocytosis!
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Vacuoles: Storage
plant cells
contractilevacuole
animal cells
central vacuole
food vacuoles
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cell membranecell boundarycontrols movementof materials in & out
recognizes signals
cytoplasmjelly-like material holding organelles in place
vacuole & vesiclesstoragetransport
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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
only in animal cells
synthesized by rER, transferred to Golgi
Where old organellesgo to die!
lyso– = break apart –some = body
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Lysosomes
white blood cells attack & destroy invaders = digest them in lysosomes
1974 Nobel prize: Christian de Duve
Lysosomes discovery in 1960s
1960 | 1974
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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 diseasebuild up undigested fat in brain cells
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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
“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
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Fetal development
15 weeks
6 weeks
syndactyly
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Apoptosis
programmed destruction of cells in multi-cellular 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
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lysosomefood digestiongarbage disposal &recycling
cell membranecell boundarycontrols movementof materials in & out
recognizes signals
cytoplasm jelly-like material holding organelles in place
vacuole & vesiclestransportstorage
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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
+
ATP
ATP
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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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Mitochondria Function
make ATP energy from cellular respiration sugar + O2 ATP fuels the work of life
Structure double membrane
in both animal & plant cells
ATP
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lysosomefood digestiongarbage disposal &recycling
cell membranecell boundarycontrols movementof materials in & out
recognizes signals
cytoplasm jelly-like material holding organelles in place
vacuole & vesiclestransport inside cellsstorage
mitochondriamake ATP energy from sugar + O2
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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
build leaves & roots & fruit out of the sugars
ATP
sugar
ATP
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Mitochondria
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Dividing MitochondriaWho else divides like that?
What does this tell us about the evolution of eukaryotes?
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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
needed = more mitochondria
What cells would have a lot of mitochondria?
active cells: • muscle cells • nerve cells
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Mitochondria are in both cells!!
animal cells plant cells
mitochondriachloroplast
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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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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 one supplies energy the other supplies raw materials
& protection
Lynn MargulisU of M, Amherst
1981 | ??
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Endosymbiosis theoryEvolution of eukaryotes
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Endosymbiosis 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
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central vacuolestorage: food, water or waste
mitochondriamake ATP in cellular respiration
chloroplastmake ATP & sugars in photosynthesis
cell wallsupport
cell membranecell boundarycontrols movementof materials in & out
recognizes signalslysosomedigestion & clean up
cytoplasm
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Cells need workers (proteins)! Making proteins
to run daily life & growth, the cell must… read genes (DNA) build proteins
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
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Proteins do all the work!
cellsDNA proteins
one of the major job of cells is to make proteins,because…
proteins do all the work!
signals
structure
enzymes
receptors
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Nucleus Function
control center of cell protects DNA
instructions for building proteins
Structure nuclear membrane nucleolus
ribosome factory chromosomes
DNA
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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
largesubunit
smallsubunit
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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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lysosomefood digestiongarbage disposal &recycling
cell membranecell boundarycontrols movementof materials in & out
recognizes signals
cytoplasmjelly-like material holding organelles in place
vacuole & vesiclestransport inside cellsstorage
mitochondriamake ATP energy from sugar + O2
nucleusprotects DNAcontrols cell
ribosomesbuilds proteins
ERhelps finish proteinsmakes membranes
Regents Biology transport vesicles
vesiclescarrying proteins
Golgi Apparatus Function
finishes, sorts, labels & ships proteins like UPS headquarters
shipping & receiving department ships proteins in vesicles
“UPS trucks”
Structure membrane sacs
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cell membranecell boundarycontrols movementof materials in & out
recognizes signals
cytoplasmjelly-like material holding organelles in place
vacuole & vesiclestransport inside cellsstorage
mitochondriamake ATP energy from sugar + O2
nucleusprotects DNAcontrols cell
ribosomesbuilds proteins
ERhelps finish proteinsmakes membranes
Golgi apparatusfinishes, packages
& ships proteins
lysosomefood digestiongarbage disposal &recycling
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central vacuolestorage: food, water or waste
mitochondriamake ATP in cellular respiration
chloroplastmake ATP & sugars in photosynthesis
cell wallsupport
cell membranecell boundarycontrols movementof materials in & out
recognizes signals
Golgi apparatusfinish & ship proteins
nucleuscontrol cellprotects DNA
endoplasmic reticulumprocesses proteinsmakes membranes
lysosomedigestion & clean up
cytoplasm
ribosomesmake proteins