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In This Lesson:
Cell Organelles
(Lesson 3 of 5)
Today is Tuesday,
th
October 18 , 2016
Pre-Class:
Scientists have put forth various estimates for
the average number of cells in the human body.
What would you guess?
Today’s Agenda
•
•
•
•
You know how you have “parts” called organs?
Well cells do too. And we’re learning them today.
An excerpt of a great bit o’ writing on cells.
Perspective.
– A “whoooooaaaa” moment.
• Where is this in my book?
– Chapter 6
By the end of this lesson…
• You should be able to describe the anatomy of
the cell.
• You should be able to visually identify many of
the cell’s parts from a diagram.
• You should be able to differentiate between
prokaryotes and eukaryotes in terms of
organelles.
Perspective
• You.
• You are a giant pile of cells and stuff put in
place by cells.
• You are a giant pile of between 1 trillion and
100 trillion cells.
• You are nothing more than a giant pile of cells.
– No offense.
• You are listening to another giant pile of cells
right now.
Perspective
• This other giant pile of cells has written some
things down to help you understand cells.
• You are a giant, integrated network of cells,
capable of thought, discovery, and emotion.
• You are a giant pile of cells capable of hearing
music in your head and recalling events that
happened years ago, to cells that may not even
be alive right now.
• You are a giant pile of cells learning about
yourself.
Introductions
• Bill Bryson – Cells
• The Inner Life of the Cell
Perspective (different kind)
• How big are cells, exactly?
• Well, the biggest single cell is an ostrich egg.
• Your biggest cell (provided you’re not an
ostrich) is your sciatic nerve.
– Graphic photo in three slides.
• For an average cell size, let’s go to The Scale of
the Universe:
– Scale of the Universe.lnk
The Biggest Cell in the World
• Ostrich egg
http://aidanmoher.com/blog/wp-content/uploads/2010/01/ostrich_egg_size.jpg
Your Biggest Cell
• Sciatic nerve
WARNING:
Graphic picture
next slide…
http://www.acticare.com/conditions/images/sciatic_nerve2.jpg
Sciatic Nerve
http://www.ilizarov.org/new1/upload/8142007102508AM3.JPG
Historical Perspective
Robert Hooke?
• The term “cell” comes to us from
Robert Hooke, who first observed what
looked like tiny rooms within a piece of
cork under an early microscope.
Historical Perspective
• Hooke gets (and deserves)
his share of credit, but the
first to observe living cells
was Anton von
Leeuwenhoek (“lay-venhoke”).
– Leeuwenhoek observed
blood cells, sperm cells,
and single-celled
organisms.
http://www.teachersparadise.com/ency/en/media/5/5e/anton_van_leeuwenhoek.png
Pushing forward…
• After Leeuwenhoek, the beginnings of
the Cell Theory began to take shape,
much in the same “trial/error” way that
we got the atomic model in chemistry:
Robert Browning
– 1824 – Henri Dutrochet: “The cell is the
basic structural unit.”
– 1831 – Robert Browning names the
nucleus.
• Same surly-lookin’ dude as Brownian motion.
– 1838 – Matthias Schleiden: “Plants are
made of cells.”
Matthias Schleiden
Pushing forward…
• 1839 – Theodor Schwann: “Animals are
made of cells.”
• 1850 – Louis Pasteur invents
pasteurization (for wine).
Theodor Schwann
– “Wait, cells are causing diseases?”
• Notably, to this point many scientists
had been proposing hypotheses for
how cells came to be, many of whom
had correctly realized all cells come
from other cells, but none of whom got
the process right.
Louis Pasteur
Pushing forward…
• 1855 – Rudolf Virchow states that cells
come from the division of previouslyexisting cells.
Rudolf Virchow
– Gold star for you, Dr. Virchow.
• All of this research had finally gotten us to
the Cell Theory:
– All cells come from other cells.
– The cell is the basic unit of structure and
function.
– All living things have one or more cells.
• TED: Lauren Royal-Woods 2012 - The Wacky
History of Cell Theory
Microscopes
• The microscope has gotten more powerful.
• Advanced electron microscopes allow us to
see amazingly small objects at the cost of
being unable to see living things.
– Tunneling microscopes now let us both view
and manipulate atoms.
– A Boy and His Atom
– Willard Wigan
– NOVA - Microscopes
Scanning Electron Microscope
• Ant
Scanning Electron Microscope
Scanning Electron Microscope
• Spider silk.
http://riki-lb1.vet.ohio-state.edu/background/echaff_empic.php
Scanning Electron Microscope
• Ehrlichia chaffeensis in cells – the cause of
Human Monocytic Erhlichiosis.
http://riki-lb1.vet.ohio-state.edu/background/echaff_empic.php
Scanning Electron Microscope
• Trichinosis spiralis (microscopic animal
parasite from undercooked meat).
http://riki-lb1.vet.ohio-state.edu/background/echaff_empic.php
Scanning Electron Microscope
• Flea
http://www.photosfan.com/electron-microscope/
Scanning Electron Microscope
• Bacterial chain on calcite rock from Spider
Cave, Yosemite National Park. (10,000x!)
http://www.caveslime.org/fmd/bacteria/
So…wait.
• The fact that we have so many cells, yet they’re so
small, begs a question…
• Why aren’t cells bigger?
– Why they’re not smaller is easier – they need to be big
enough to at least have some necessary contents.
• Discuss this with your neighbor.
• It turns out the answer is related closely to two
geometric calculations…
Surface Area to Volume Ratio
A Review
Cube 1
2 cm
4 cm
Cube 2
2 cm
2 cm
4 cm
4 cm
Cube 1
Cube 2
Proportion
Volume
8 cm3
64 cm3
8x more volume
Surface Area
24 cm2
96 cm2
4x more surface
Proportion
3x more surface 1.5x more surface
SA to Volume Ratio
• Observe how volume is the same, but surface area
is quite different:
Think of it this way…
• If you buy a gallon of water in one
bottle…
• …and then you buy a gallon of
water in many bottles…
• …which option gets you more
water?
– Either choice. They’re the same.
• But which option uses more
packaging material?
– The smaller bottles.
• Key: Think of packaging material
like surface area.
https://pfiesterpfit.files.wordpress.com/2011/05/gallon_of_water.jpg
http://www.exchange3d.com/images/uploads/aff4269/Arrowhead.jpg
Surface Area to Volume Ratio
• Diffusion prevents the growth of larger cells
because things like CO2 and H2O simply take
too long to diffuse into the center of the cell.
• DNA prevents the growth of larger cells
because it has to control cellular functions but
can only do so from the nuclei.
– The largest cells are often multi-nucleated.
And speaking of controlling the cell…
• It’s time we start discussing organelles.
– The “little organs” of the cell.
• But why even have organelles at all?
• Organelles allow for:
chloroplast
– Specialized functions.
• Like cilia and flagella.
– Containers.
Golgi
mitochondria
• In which pH can change or dangerous enzymes like
those in the lysosome can be stored.
ER
– Membranes.
• Many reactions take place in the membranes of cells.
Your Cells Have Jobs
• In order to keep on livin’, cells need to:
– Make protein.
• PROTEINS CONTROL EVERY CELL FUNCTION.
– Make energy.
• For maintenance and growth.
– Make more cells.
• For growth (of the organism), repair, and renewal.
• Did I mention proteins do all the work?
All Cells Have Jobs
• It turns out that not all cells have all
organelles.
• Some, in fact, have very few indeed.
• If you think in terms of the structures cells
have, you can divide all the cells in the world
into two categories:
– Prokaryotic
– Eukaryotic
Prokaryotes vs. Eukaryotes
• Prokaryotes (“before kernel”):
– No nucleus, no membranebound organelles.
– Simple and old.
– Example: Bacteria and Archaea
• Eukaryotes (“true kernel”):
– Nucleus, membrane-bound
organelles.
– Relatively new and more
complex.
– Example: Eu!
http://asweknowit.net/images_edu/DWA%205%20eukaryote.jpg
http://upload.wikimedia.org/wikipedia/commons/thumb/d/db/Prokaryote_cell_diagram_pt.svg/573px-Prokaryote_cell_diagram_pt.svg.png
Nucleus
• Structure
– Has its own double-membrane
called the “nuclear envelope,”
which has lots of pores.
– Nuclear lamella provides shape.
– Contains/protects
DNA/chromosomes.
• Function
Found In
Prokaryotes?
✘
Found In Eukaryotes?
Animals?
Plants?
✓
✓
– The “control center” of the cell.
– Has a nucleolus (area in
nucleus) that makes ribosomes.
http://www.cartage.org.lb/en/themes/Sciences/Zoology/AnimalPhysiology/Anatomy/AnimalCellStructure/Nucleus/cellnucleus.jpg
Pores in the Nuclear Membrane
• Remember what needs to pass through here?
• A little molecule by the name of mRNA?
Coloring Sheet
The Big Idea (or Central Dogma)
Transcription
DNA
Translation
RNA
Protein
Trait
Replication
NOTE: DNA Replication does not have to
happen before transcription.
The Big Idea (or Central Dogma)
Transcription
DNA
Nucleus
Translation
RNA
Protein
Cytoplasm @
Ribosome
Trait
large subunit
 They’re small…
Ribosomes
small
subunit
• Structure
– Made of two subunits (large and small) of rRNA.
• Function
– Protein manufacturing.
• Other
Found In
Prokaryotes?
– There are two types of ribosomes:
✓
Found In Eukaryotes?
Animals?
Plants?
✓
✓
• Bound ribosomes (attached to the ER)
• Free ribosomes (somewhere in the cytosol)
– They’re also evolutionarily old and found in every living
thing.
http://library.thinkquest.org/04apr/00217/images/content/ribosome.jpg
Ribosomes
0.08mm
Ribosomes
Rough
ER
Smooth
ER
Nucleus & Ribosomes Interaction
nuclear
membrane
DNA is used as a model
to produce mRNA in
the nucleus…
DNA
Nucleus
nuclear pore
mRNA
small
ribosomal
subunit
mRNA
large
ribosomal
subunit
cytoplasm
…and then exits through a
nuclear pore to meet with both
halves of the ribosomes in the
cytosol.
Coloring Sheet
Now for the unique structures…
• Cell Wall
– Rigid, relatively strong, made
of cellulose.
• Helps support plants.
• Three layers (moving inward):
– Primary cell wall
– Middle lamella
– Secondary cell wall
Found In
Prokaryotes?
✓
http://biology.unm.edu/ccouncil/Biology_124/Images/cellwall.jpeg
Found In Eukaryotes?
Animals?
Plants?
✘
✓
Coloring Sheet
Cell Membrane
• Found in all cells.
• Surrounds the cell.
• Allows for membrane transport (diffusion,
osmosis, et cetera) and serves as a barrier.
• A LOT more to come on this one.
Found In
Prokaryotes?
✓
Found In Eukaryotes?
Animals?
Plants?
✓
✓
Coloring Sheet
Endoplasmic Reticulum (ER)
• Usually found near the nucleus.
– Rough ER: Lined with ribosomes
(which make protein).
• Rough ER is a stack of discs.
• Proteins are made and transported
for export to other cells.
– Smooth ER: No ribosomes. Drug
detox. Makes lipids. Has calcium.
Converts glycogen to glucose. ??
• Smooth ER is a tube shape.
• Lipids are kept local.
• Makes cell membrane.
• Both are capable of some
transport.
Found In
Prokaryotes?
✘
Found In Eukaryotes?
Animals?
Plants?
✓
✓
http://images.teamsugar.com/files/upl1/1/13839/15_2008/MV5BMjA0NjI0ODgzNF5BMl5BanBnXkFtZTcwMDAxNDUyMQ@@._V1._SY400_SX60
0_.jpg https://illnessesanimalsplants.wikispaces.com/file/view/smooth_&_rough_ER.jpg/31839797
Endoplasmic Reticulum
Endoplasmic Reticulum
Rough ER: Protein Synthesis
cisternal
space
polypeptide
signal
sequence
ribosome
mRNA
membrane of
endoplasmic reticulum
cytoplasm
Get it?
Case in Point: Organelle “Trends”
• Which type of cell might have a lot of smooth
ER?
– Maybe a reproductive organ’s cell? Something
that uses a lot of hormones.
– Maybe a liver cell? Something that will be
involved in alcohol detoxification.
• Which type of cell might have a lot of rough
ER?
– Maybe a pancreatic cell? Something that needs a
lot of protein.
Coloring Sheet
Vesicles
• Not technically organelles, they are
membrane-bound “packages” of
the cell, usually from the Golgi or
cell membrane.
• A sac that contains a substance.
• Pinch off organelles and move
through the cytoplasm to a
destination.
– What might be a destination?
Nerve cell vesicles releasing contents 
http://www.cnsforum.com/content/pictures/imagebank/hirespng/vesicle_fusion.png
Vesicles
• Vesicles are small “bubbles” made of cell membrane.
• They’re used to carry stuff around the cell, out of the
cell, or into the cell.
• Think of them like little envelopes for shipping stuff.
Lysosome
• Structure
– A vesicle containing digestive
enzymes.
• Function
– Break down worn out organelles or
other cell parts (autophagy – literally
“eating oneself”).
– Break down organic molecules within
the cell or already-eaten other cells.
– Like a garbage disposal for the cell.
• Plant cells have them, but they’re
not as common as in animal cells.
http://library.thinkquest.org/12413/img/lysosome.jpg
Found In
Prokaryotes?
✘
Found In Eukaryotes?
Animals?
Plants?
✓
✓
Lysosome
http://www.yksd.com/distanceedcourses/Courses09/Biology/lessons/FirstQuarterLessons/Chapter1/images/Lesson2/25lysosome.png
Aside: Lysosomal Diseases
• Tay-Sachs Disease and Gaucher’s Disease
– Failure to break down fatty acid derivatives.
– Tay-Sachs is common in Ashkenazic Jews.
• Many lysosomal diseases (there are around 40
of them) result in a buildup of wastes within
the cell due to the digestive enzymes not
functioning.
Lysosomes
Apoptosis
• When cells need to be replaced, they undergo
something referred to as “programmed cell
death,” or apoptosis.
– Literally, they digest themselves to death.
• The lysosome plays a role in this process too, by
releasing enzymes into the cytoplasm.
– It’s like if your stomach opened and ate you.
• This is the same process used to eliminate the
tailbone and webbing between your fingers you
had whilst still in yo’ mom.
Aside: Syndactyly – “Together Fingers”
• And if that apoptotic
process somehow fails?
Case in Point: Organelle “Trends”
• Which type of cell might have a lot of
lysosomes?
– Maybe a leukocyte (white blood cell)? Something
that digests a lot.
• Another look at digestion:
– Amoeba Eats Two Paramecia video
Coloring Sheet
Golgi Apparatus
(or Golgi Body)
• Structure
– A blobby stack of membranes in the cytosol.
– Cis face is the receiving side facing the nucleus/ER;
Trans face is the sending side facing the membrane.
• Function
– Finishes, sorts, tags, and ships cell products out of the
cell.
– Ships products in vesicles.
Found In Eukaryotes?
Found In
Prokaryotes?
✘
Animals?
Plants?
✓
✓
http://employees.csbsju.edu/HJAKUBOWSKI/classes/ch331/cho/ergolgi.jpeg
Golgi Apparatus
Vesicular Transport
Cytosol
ER
Golgi
Apparatus
Protein
Vesicle
budding from
ER
Ribosome
Migrating
transport
vesicle
Fusion
of vesicle
with Golgi
Apparatus
DNA
mRNA
Vesicle
containing
protein
Vesicle
containing
processed
protein
http://employees.csbsju.edu/HJAKUBOWSKI/classes/ch331/cho/ergolgi.jpeg
Endomembrane System
• What you just saw on the previous slide is a good
illustration of the endomembrane system, which
is the network of membrane-bound organelles
within the cytoplasm:
–
–
–
–
–
–
–
Nucleus
ER
Golgi Apparatus
Vesicles
Vacuoles
Lysosomes
Cell membrane
Case in Point: Organelle “Trends”
• Which type of cell might have a lot of Golgi
apparatuses?
– Maybe a glandular cell? Something that secretes
a lot of stuff, like endocrine glands (pituitary
gland, pancreas, testes, ovaries) or the salivary
gland.
Coloring Sheet
Quick Analogy
• Let’s say you want to make someone a present
and mail it to them.
– First you would make the gift (like a ribosome
makes protein)…
– …then you would move it in your house toward
the door (like rough ER moves protein)…
– …then you would ship it to your friend (like the
Golgi ships particles)…
– …in a box (like a vesicle).
Mitochondria
• Structure
Found In
Prokaryotes?
✘
Found In Eukaryotes?
Animals?
Plants?
✓
✓
– Two membranes that form two compartments.
– Have their own DNA (!).
– More structure details next slide.
• Function
– Often called the powerhouse of the cell, and there are an
average of 100-1000 for each cell (sometimes even just 1).
– Uses organic molecules to produce ATP (adenosine
triphosphate), helps in respiration.
• More coming on this next unit…
• Grammar Note:
– One mitochondrion, two mitochondria…
Mitochondria
Structure
• The inner membrane of the
mitochondrion is highly
folded.
– The folds are called cristae,
and they increase the surface
area of the membrane.
• The innermost space of the
mitochondrion is known as
the matrix.
– The matrix contains DNA,
enzymes, and ribosomes.
Mitochondria
Structure
Mitochondria
Structure
• So why do mitochondria need cristae? Why
increase the surface area?
– Because the cristae contain membrane-bound enzymes!
Mitochondria
Evolution
• They have their own DNA, ribosomes, and
enzymes. They move and divide on their own.
• Scientists think mitochondria once lived on their
own…and were actually bacteria!
• Need more evidence?
http://evolution.berkeley.edu/evolibrary/images/endosymbiosis/mitoch
ondria.gif
Mitochondria
mtDNA
• mtDNA is the name given to mitochondrial DNA.
• It’s inherited directly from the maternal side of the
family, meaning it’s almost always unchanged from
your mother’s mtDNA…whose mtDNA was
unchanged from her mother too.
• This makes it valuable for forensics, as it’s not as
fragile as nuclear DNA and can be found much more
readily in hair samples.
Case In Point: Organelle “Trends”
• Which type of cell might have a lot of
mitochondria?
– Maybe a muscle cell? Something that needs a lot
of energy.
Coloring Sheet
Aside: Muscle Cells
• Muscle cells act in cooperation with others.
• As a result, their organelles have different
names:
– Sarcolemma = Plasma Membrane
– Sarcoplasmic Reticulum = Endoplasmic Reticulum
– Sarcosomes = Mitochondria
– Sarcoplasm = Cytoplasm
Chloroplast
• Structure
– Similar to mitochondria:
•
•
•
•
Double membrane
Ribosomes
DNA
Move and divide like bacteria
– More structure details next slide.
• Function
– Photosynthesis.
– Green pigmentation.
http://micro.magnet.fsu.edu/cells/chloroplasts/images/chloroplastsfigure1.jpg
Found In
Prokaryotes?
✘
Found In Eukaryotes?
Animals?
Plants?
✘
✓
Chloroplast
Structure
• The two-membrane structure is like
mitochondria.
• The innermost space is called the
stroma.
– In mitochondria, it’s the matrix,
remember?
• Inside the stroma are stacks of disks.
– The disks are thylakoids.
– The stacks are grana (singular:
granum).
• The disks increase the surface area of
the membrane just like the cristae
do.
Chloroplast
Plastids
• Plant and algal cells have a bunch of closelyrelated organelles called plastids.
• Chloroplasts
– Green pigments and photosynthesis.
• Amyloplasts
– Starch storage in roots/tubers.
• FYI: Starch-related words tend to start in “amyl-.”
• Chromoplasts
– Pigment for flowers and fruit.
• FYI: Anything related to color or visibility
Mitochondria & Chloroplasts
• They are the hipsters of the cell:
– They’re not part of the endomembrane system.
• Did you see how they weren’t part of the nucleus > ER
> Golgi > membrane chain?
– They grow and reproduce on their own.
– They get protein from their own ribosomes (which
are like those of bacteria) or the free ones in the
cell.
– They have a circular chromosome (like bacteria).
Coloring Sheet
Case In Point: Organelle “Trends”
• Would a cell from an onion contain a lot of
chloroplasts?
– Nope – onions grow underground.
Central Vacuole
• Structure
– Plants only have large,
central vacuoles.
Entire Cell
– Takes up most of the cell
(plants only).
• Function
– Storage for water and
food (plants/animals).
– Supports the cell when
full (plants only).
Vacuole 
• Animals have smaller
ones.
• Prokaryotes rarely have
them.
Found In
Prokaryotes?
✘
Found In Eukaryotes?
Animals?
Plants?
✓
✓
[small] [large]
http://www.ccs.k12.in.us/chsBS/kons/kons/eukaryotic%20cell/cytoplasm_and_its_associated_str_files/image017.jpg
Vacuoles
Types
• Food Vacuoles
– Help the cell “eat” stuff.
– Fuse with lysosomes for digestion.
• Contractile Vacuoles
– Regulate H2O balance by pumping water out.
• Central Vacuoles
– Store water and help keep a plant cell rigid.
– Store pigments and ions.
– Store compounds that defend against herbivores.
– Surrounded by the tonoplast.
Central Vacuole Support
http://upload.wikimedia.org/wikipedia/commons/thumb/a/ab/Turgor_pressure_on_plant_cells_diagram.svg/2000pxTurgor_pressure_on_plant_cells_diagram.svg.png
Coloring Sheet
Peroxisomes
Not on your coloring sheet
• Structure
– Digestive enzyme sac, much like the
lysosome in that it must be kept
separate from the cell.
• Function
– Break down fatty acids to sugars (yes, fat
to sugar).
– Detoxify cell by breaking down alcohol
and other poisons.
– Produce hydrogen peroxide (H2O2).
• The peroxide is toxic and must be broken
down to water.
• Other
– Made by the ER.
– Sometimes called microbodies.
Found In
Prokaryotes?
✘
Found In Eukaryotes?
Animals?
Plants?
✓
✓
Aside: Peroxisomal Diseases
• X-linked Adrenoleukodistrophy
– Fatty acids can’t get metabolized, resulting
ultimately in nerve damage.
• See Lorenzo’s Oil.
• Zellweger Syndrome
– Proteins cannot be imported into the peroxisome.
Cytoskeleton
• Structure
– Made of microfilaments,
microtubules, and intermediate
filaments.
• Microfilaments are made of a
protein called actin.
• Microtubules are made of a protein
called tubulin.
• Function
– Help cells move (make up flagella
and cilia).
– Help move things within cells.
– Support organelles.
– Aid in cell division.
– Form centrioles.
http://bcrc.bio.umass.edu/gbi/images/mtsandactin.jpg
Found In
Prokaryotes?
✓
Found In Eukaryotes?
Animals?
Plants?
✓
✓
Cytoskeleton
• Actin
• Tubulin
• Nuclei
Motor Proteins
• So you know how vesicles move through the
cytoplasm?
• Well, they don’t float randomly.
• Motor proteins help them “walk” down the
cytoskeleton.
• Video: Kinesin Motor Protein
Other Parts of the Cell
http://www.uic.edu/classes/bios/bios100/lectures/cilia_flagella.jpg
Cilia and Flagella
Found In
Prokaryotes?
✓
Found In Eukaryotes?
Animals?
Plants?
✓
✘
• As you might imagine, some cells need to move.
• To do this, they use flagella (singular: flagellum) and
cilia (singular: cilium).
– Flagellum (made of protein)
• A long “whip-like” structure usually on one end of the cell.
• Most cells have one or two flagella.
– Cilia (made of protein)
• Many short “hair-like” structures along the outside of the cell.
• Most cells have lots of cilia.
• Cilia also move other things along the surface of the cell.
• Both are anchored to the cell by a basal body, which is
like a centriole (next organelle).
Coloring Sheet
Centrioles
• Structure
Found In
Prokaryotes?
Not on your coloring sheet
– One pair in each cell.
– Short, rod-shaped structure.
– Made of nine bundles of three
microtubules.
• Function
– Guides cell division in animals.
http://micro.magnet.fsu.edu/cells/centrioles/images/centriolesfigure1.jpg
✘
Found In Eukaryotes?
Animals?
Plants?
✓
✘
Cytoplasm
• You know this one.
• New stuff:
– The inner cytoplasm is watery.
– The outer cytoplasm is more like a gel and is called
the cortex.
– The cytoplasm sometimes circulates around the
cell. This is called cytoplasmic streaming.
Coloring Sheet
Starting here…
A Little Review
http://www.bchs.k12.va.us/BCHS-Webpage/HSWEBPAGE/SchoolSite/assets/plantcell.gif
A Little More Review
• Let’s try some cell anatomy with a little more
detail…
• http://www.sheppardsoftware.com/health/an
atomy/cell/index.htm
It’s POGIL Time!
• Organelles in Eukaryotic Cells POGIL
Closure
• Organelle Charades, anyone?