eykaryotes

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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, archaea

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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…

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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

Cytoplasmlattice-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

cytoplasmlattice 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

cytoplasmlattice-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

cytoplasmlattice-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

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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

cytoplasmlattice 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