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Eukaryotic cell
structure
The Cell factory
 Organelles
 Highly specialized structures within the cell
 Little organs
 2 major divisions of the eukaryotic cell
 Nucleus
 The “brain”
 DNA
 Cytoplasm
 Portion outside the nucleus but inside the cell membrane
2 types of Eukaryotic cells
 Plant cells
 Animal cells
 What are the differences? (write them down!!!)
Nucleus
 Brain of the cell
 Office of the factory
 Contains nearly all the cell’s DNA and
with it the coded instructions for making
PROTEINS and other important
molecules
Nuclear envelope
 Surrounds nucleus
 Made of 2 membranes
 Dotted with thousands of nuclear pores
 How do we get messages, instructions and
blueprints out of the office?
 Allow material to move in and out of nucleus by
using “little runners” such as proteins, RNA and
other molecules
Inside the nucleus we
see…
 Contain a granular material called…
 CHROMATIN
 Chromatin= DNA + protein
 Usually spread out in nucleus
 During cell division, chromatin clumps
together or condenses…we call this….
 CHROMOSOMES
Chromosomes
 Threadlike structures that contain genetic
information that is passed on from one
generation to the next
Nucleolus
 Small dense region inside the nucleus
 Function: assembly of ribosomes begin…
Ribosomes
 Most important function of cell is…
 Making proteins
 Proteins regulate a zillion different things
 Like…
 Proteins are assembled ON Ribosomes
 Ribosomes are small particles of protein &
RNA (what’s RNA?)
 They follow instructions from the nucleus to
make proteins…follow the orders from the
“head haunchos” in the main office
 Scattered throughout the cell
 They are like little factories
 If a cell’s main function is making proteins, how
many ribosomes are you going to have?
Endoplasmic reticulum
(ER)
 Internal membrane system
 The site where the lipid components of
the cell membrane are assembled, along
with proteins and other materials
exported from the cell
 2 types
 Smooth ER
 Rough ER
Rough ER
 Involved in protein making (synthesis)
 So what are we going to see on it?
 ribosomes
 Once a protein is made, it leaves the
ribosome and goes into the Rough ER
 The rough ER then modifies the protein
 All proteins that are exported by the cell
are made on the RER
 Membrane proteins are made on the
RER too
Smooth ER
 NO ribosomes on it
 Looks smooth
 Contains collections of ENZYMES that have
specialized tasks
 What do enzymes do?
 Tasks include:
 Synthesis of membrane lipids
 Detoxification of drugs
 Liver cells
 Big in detox therefore….what do u think liver cells have a
lot of?
Golgi Apparatus
 Discovered by Italian scientist Camillo Golgi
 Once proteins are done being “modified” in the
RER, they move onto the Golgi apparatus
 Looks like a stack of pancakes
 Function: modify, sort, and package proteins
and other materials from the ER for STORAGE
or SECRETION outside the cell
 Proteins are “shipped” to final destination
 They are the CUSTOMIZATION SHOP
 Finishing touches on proteins before they leave
factory
Lysosomes
 (Lie-so-soh-mz)
 The factory’s clean-up crew
 It’s an Organelle filled with
enzymes
 Function: Digestion (break
down) of lipids,
carbohydrates, and proteins
into smaller molecules that
can be used by the cell
 Also digest organelles that
have outlived their
usefulness
What do you think happens if
lysosomes malfunction?
 A bunch of “junk” build up in the cell
 Is this good?
 Many human diseases result from
malfunction of lysosome
 Tay-Sachs disease
Vacuoles
The factory’s storage place
Only in certain cells
Sac-like organelles
Function: stores material such as water,
salts, proteins, and carbohydrates
 Plant cells have a single, large central
vacuole
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 Pressure of central vacuole allows plants to
support heavy structures
Single-celled organisms and
some animals also have
vacuoles…
 Paramecium
 Contractile vacuole
 Contracts rhythmically to pump excess water
out…this maintains what?
 homeostasis
What is the one thing
all living things need
to eat, breath,
reproduce, move and
much more?
ENERGY!!!!
Two ways cells get
energy…
 From food molecules
 From the sun
Mithochondria
 Convert chemical energy stored in food
into compounds that are more convienent
for the cell to use
 Has 2 membranes
 Inner membrane
 Outer membrane
 Nearly all come from the ovum
 You get your mitochondria from your mom!
Chloroplasts
 Capture energy from the sunlight and
convert it into chemical energy…what is
this process called?
 PHOTOSYNTHESIS
 Like solar power for plants
 2 membranes
 Inside: large stacks of other membranes
that contain chlorphyll
Organelle DNA
 Chloroplasts and
mitochondria contain
their own genetic info
 In form of small DNA
molecules
Lynn Margulis
 American biologist
 Chloroplasts and
mitochondria are
descendents of
prokaryotes
She said…
 Ancient Prokaryotes from wayyyyy back in the
day had a symbiotic relationship with the
ancient eukaryotes
 What is symbiotic? (review ecology!!!)
 The prokaryotes lived inside the eukaryotes
 There were prokaryotes that used oxygen to
make energy (ATP)
 Mitochondria
 There were prokaryotes that used
photosynthesis to get energy
 Chloroplasts
Endosymbiotic Theory
 Idea that
mitochondria and
chloroplasts evolved
from prokaryotes
Cytoskeleton
 Supporting structure and
transportation system
 Network of protein filaments that helps
the cell to maintain its shape and to help
the cell move
 2 main type of filaments
 Microtubules
 Microfilaments
Microfilaments
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Threadlike structures
Made of protein called ACTIN
Extensive networks
Tough, flexible framework
Help cells move
Assembly and disassembly helps cells
move (like amoebas)
Microtubules
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Hollow structures
Made of proteins called TUBULINS
Maintain cell’s shape
Important in cell division
 Make mitotic spindle (separates
chromosomes)
 Help build projections from cell surface…
Cilia and Flagella
 Plural: cilium and flagellum
 Enable cells to swim rapidly through liquid
 Like oars of a boat
Centrioles
 Only animal cells
 Made of protein
TUBULIN
 What else is made of
tubulin?
 Near nucleus
 Help organize cell
division
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Antwon van Leeuwenhook
Robert Hook
Cell Theory
Electron microscope
Prokaryote
Eukaryote
Organelles
Cytoplasm
Nuclear envelope
Chromatin
Nucleus
Ribosome
Smooth Endoplasmic reticulum
Rough endoplasmic reticulum
Course adjustment knob
Fine adjustment knob
Proteins
DNA
Contractile vacuole
Central Vacuole
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Golgi apparatus
Lysosome
Vacuole
Mitochondrian
Chloroplast
Cytoskeleton
Centriole
Mictrotubule
Microfilament
Theodor Schwann
Matthias Schleiden
Rudolph Virchow
Lynn Margulis
Endosymbiotic Theory
Cilia
Flagella
Photosynthesis
Tay-Sachs disease