CELLS!
CELLS!
PROKARYOTIC vs. EUKARYOTIC
(prokaryotes vs. eukaryotes)
Prokaryotes (bacteria)
Simple organism
Smaller
Cytoplasm
Cell Membrane
Cell Wall
Circular DNA (“nucleoid region”)
Some have flagella or pili
No membrane-bound organelles
Harvest light (photosynthesis,
decompose/recycle dead organisms,
some cause disease, involved in
important industrial processes
Eukaryotes
★ Complex organism
★ Larger
★ Cytoplasm
★ Cell membrane
★ Cell Wall (plants, fungi
and some protists)
★ Some have flagella or
cilia
★ Have membrane-bound
organelles
CELLS!
PROKARYOTE
vs.
EUKAROTE
Common Features
CELLS!
PROKARYOTE
vs.
EUKAROTE
Electron Micrograph
http://www.stolaf.edu/people/giannini/cell/nuc.htm
EUKARYOTES
★
★
Greek = “true nucleus”
Compartmentalized with organelles (membranebound structures)
★
Eukaryotic cells include: plant, animal, fungi, protist
PLANT
vs.
ANIMAL
EUKARYOTES
PLANT
vs.
Electron Micrograph
ANIMAL
EUKARYOTIC ORGANELLES
PLANT
ANIMAL
★ Cell Wall
★ Centriole
★ Chloroplast
★ Cilia or Flagella
★ Large central vacuole
★ Many small vacuoles
★ Cell/Plasma Membrane
★ Cell/Plasma Membrane
★ Cytoplasm/Cytosol
★ Cytoplasm/Cytosol
★ Mitochondria
★ Mitochondria
★ Ribosomes
★ Ribosomes
★ Nucleus
★ Nucleus
★ Nucleolus
★ Nucleolus
★ Nuclear Envelope/Membrane
★ Nuclear Envelope/Membrane
★ Rough Endoplasmic Reticulum (E.R.)★ Rough Endoplasmic Reticulum
★ Smooth E.R.
★ Smooth E.R.
★ Lysosomes
★ Lysosomes
★ Golgi Body/Apparatus
★ Golgi Body/Apparatus
★ Cytoskeleton
★ Cytoskeleton
EUKARYOTIC ORGANELLES
Structure
Nucleus
Nucleolus
Endoplasmic Reticulum
(Smooth & Rough)
Golgi Apparatus
Lysosomes
Mitochondria
Chloroplasts
(Plant)
Description
Function
EUKARYOTIC ORGANELLES
Structure
Centrioles
(Animal)
Cytoskeleton
Flagella/Cilia
(Animal, fungi and some
protists)
Central Vacuole (Plant)
Cell Wall
(Plant)
Cytoplasm/Cytosol
Ribosomes
Description
Function
EUKARYOTIC ORGANELLES
THE NUCLEUS
★ Latin = “kernel” or “nut”
★ First described by Robert Brown (1831)
★ Most eukaryotic cells contain one central nucleus
★Fungi have many nuclei
★ Contains Nucleolus (where synthesis of ribosomal RNA takes place)
★ Nucleus protected by Nuclear Envelope/Membrane (which
contains nuclear pores)
Structure
Description
Function
Nucleus
Usually spherical surrounded by double
membrane that contains chromosomes
Control center of cell; directs
protein synthesis and cell
reproduction.
Site of genes for ribosomal RNA
(rRNA) synthesis
Assembles ribosomes
Nucleolus
EUKARYOTIC ORGANELLES
THE NUCLEUS
http://www.cartage.org.lb/en/themes/Sciences/Zoo
logy/AnimalPhysiology/Anatomy/AnimalCellStruct
ure/Nucleus/Nucleus.htm
http://www.frontiers-ingenetics.org/en/pictures/nucleus_1.jpg
EUKARYOTIC ORGANELLES
THE ENDOPLASMIC RETICULUM
★ Endoplasmic = “within the cytoplasm”
★ Reticulum = Latin for “a little net”
★ ROUGH E.R.: Contain many ribosomes, which appear pebbly or
“rough”, and are destined to be exported from the cell;
synthesizes proteins.
★ SMOOTH E.R.: Relatively few or no ribosomes; may contain
enzymes which can 1) carry out lipid synthesis (testes, intestine,
and brain) or;
2) carry out detoxification of drugs (liver)
Structure
Endoplasmic Reticulum
(Smooth & Rough)
Description
Network of highly folded
phospholipid membranes
within the cytoplasm
Function
Forms compartments and
vesicles; participates in
protein and lipid synthesis;
transports synthesized
proteins
EUKARYOTIC ORGANELLES
THE ENDOPLASMIC RETICULUM
http://www.ccs.k12.in.us/chsBS/kons/kons/eukaryotic%2
0cell/cytoplasm_and_its_associated_str_files/image002.j
pg
http://academic.brooklyn.cuny.edu/biology/bio4fv/page/r
ougher.htm
EUKARYOTIC ORGANELLES
THE GOLGI BODY/APPARATUS
★ Flattened stacks of tubular membranes
★ Smooth, membranous structure located near the middle of the
cell
★ Receives proteins and lipids from the E.R.
★ Abundant in glandular cells
★ Modifies and sorts proteins
★ Packages proteins into membrane-bound structures, called
vesicles, to be sent to appropriate destinations
★ Similar to a post office
Structure
Golgi Body/Apparatus
Description
Flattened stacks of tubular
membranes
Function
Sorts, packages and
transports proteins for
export from the cell
EUKARYOTIC ORGANELLES
THE GOLGI BODY/APPARATUS
http://www.bu.edu/histology/i/20303ooa.jpg
http://media-2.web.britannica.com/eb-media/52/116252004-9615DB80.jpg
EUKARYOTIC ORGANELLES
THE LYSOSOME
★ Membrane-bounded digestive vesicles
★ Arise from the Golgi Apparatus
★ Contain degrading enzymes which break down old organelles
★ Enzymes also function to eliminate harmful or foreign cells
through phagocytosis
★ Include microbodies (glyoxysome, peroxisome)
Structure
Lysosome
Description
Vesicles derived from Golgi
apparatus that contain
digestive enzymes
Function
Digests worn-out organelles
and foreign or harmful cells;
acts like a “garbage disposal”;
plays a role in cell death
(“suicide sacs”)
EUKARYOTIC ORGANELLES
THE LYSOSOME
http://www.cartage.org.lb/en/themes/sciences/zoology/A
nimalPhysiology/Anatomy/AnimalCellStructure/Lysosom
es/lysosome.jpg
http://www.stolaf.edu/people/giannini/cell/lys/autophag.j
pg
EUKARYOTIC ORGANELLES
EUKARYOTIC ORGANELLES
THE MITOCHONDRION
★ Plural = Mitochondria
★ Peanut-shaped with outer membrane and highly folded inner
membrane (cristae)
★ Have their own DNA (mitochondrial DNA or mDNA) important
for oxidative metabolism
★ Transform energy for the cell; “powerhouse” of the cell
★ Similar to a battery, generator or power plant
★ Cells have many mitochondria (ex: liver cells have up to 2000!)
★ Each time the cell divides, a mitochondrion divides in two
Structure
Mitochondria
Description
Peanut shaped structure
with double membrane
(outer membrane and highly
folded inner membrane
called cristae)
Function
“Powerhouse” of the cell;
sites of oxidative
metabolism
EUKARYOTIC ORGANELLES
MITOCHONDRIA
http://academic.brooklyn.cuny.edu/biology/bio4fv/page/
mito.gif
EUKARYOTIC ORGANELLES
THE CHLOROPLAST
★ Greek: chloro = “green”; plasts = “form “ or “entitiy”
★ Commonly in plant cells
★ Contain pigment called chlorophyll (gives plants their green color)
★ Carry out photosynthesis
★ Typically contain one to several hundred
★ Contain two membranes; closed compartment of stacked
membranes called grana which have disk-shaped structures called
thylakoids ; surrounding thylakoid is a fluid matrix called stroma
★ Other DNA-containing organelles in plants = plastids (leicoplasts;
amyloplasts)
Structure
Chloroplast
Description
Flat, disk-shaped green
organelle with two
membranes; contain
chlorophyll, a photosynthetic
pigment
Function
Site of photosynthesis;
produces food for the cell
EUKARYOTIC ORGANELLES
CHLOROPLAST
http://virtualbiologytutor.co.uk/images/chlo
roplast.jpg
http://upload.wikimedia.org/wikipedia/commons/4/49/Pl
agiomnium_affine_laminazellen.jpeg
EUKARYOTIC ORGANELLES
THE CENTRIOLES
★ Microtubule Assembly Centers
★ Composed of 9 triplets of microtubules
★ Microtubules = long, hollow cylinders which influence cell shape,
move the chromosomes in cell division, and provide structure for
flagella and cilia
★ Barrel-shaped organelles found in animals and most protists
★ Plants and fungi lack centrioles
★ Occur in pairs, usually at right angles
Structure
Centrioles
Description
Occur in pairs and made of
microtubules; in animal cells
and most protists
Function
Important in cell division,
cell shape and structure for
flagella and cilia
EUKARYOTIC ORGANELLES
CENTRIOLES
http://images.protopage.com/view/721389/3
ydo50yjpdnqy8ag4flqbd1un.jpg
http://upload.wikimedia.org/wikipedia/commons/4/49/Pl
agiomnium_affine_laminazellen.jpeg
EUKARYOTIC ORGANELLES
THE CYTOSKELETON
★ Interior framework of the cell
★ Network of protein fibers that support the shape of the cell and
anchor organelles to fixed locations
★ Stretches the plasma membrane like the poles on a circus tent!
★ Allows cells to alter rapidly alter shape
Structure
Cytoskeleton
Description
Network of protein
filaments
Function
Provides internal structural
support; helps in cell
movement
EUKARYOTIC ORGANELLES
CYTOSKELETON
http://www.ibri.org/RRs/RR05
1/51cytoskeleton.gif
http://www.noble.org/press_release/plantbi
o/blancaflornasa/cytoskeleton.jpg
http://migration.files.wordpress.com/2007
/07/cytoskeleton02.jpg
EUKARYOTIC ORGANELLES
FLAGELLA/CILIA
★ Made of microtubules
Aid the cell in locomotion or feeding
Motion is similar to that of oars in a rowboat
Flagella are longer projections that move with a whip-like motion
Cilia are shorter, numerous projections that look like hairs.
Some protists use a pseudopod (“false foot”) to crawl; similar to
squeezing a water balloon at one end forces the balloon to bulge
out at the other end.
Structure
Flagella/Cilia
Description
Cellular extensions made up
of pairs of microtubules
Function
Aid the cell in locomotion
(movement) or feeding
EUKARYOTIC ORGANELLES
CILIA
FLAGELLA
http://www.ibri.org/RRs/RR05
1/51cytoskeleton.gif
http://img.spar
knotes.com/fig
ures/2/2faaa24
e75677b6732cd2
4bf35c357da/fla
gella.gif
http://upload.wikimedia.
org/wikipedia/commons
/thumb/8/82/Eukaryotic
_cilium_diagram_pl.svg/
120pxEukaryotic_cilium_diagr
am_pl.svg.png
http://www.bio.miami.edu/~cmalle
ry/150/proceuc/c27x7x3flagella.jpg
EUKARYOTIC ORGANELLES
CENTRAL VACUOLE
★ In Plant cells:
Large sac used to store mainly water and other materials (sugars,
ions and pigments)
Helps to increase the surface-to-volume ratio by applying pressure
to cell membrane.
In Animal cells: contain many small vacuoles for temporary storage
Structure
Central Vacuole
Description
In plant cells, large organelle
filled with mainly water, and
other materials; takes up
most of cell
Function
Storage center for water
and other materials; helps
maintain volume of cell
EUKARYOTIC ORGANELLES
CENTRAL VACUOLE
http://www.ibri.org/RRs/RR05
1/51cytoskeleton.gif
http://micro.magnet.fsu.edu/cells/plants/imag
es/plantvacuolesfigure1.jpg
http://i
mages.
protopa
ge.com
/view/7
21661/d
2fz30gp
lfcumnt
whpv6jr
25g.jpg
Plant Cell
http://biology.unm.edu/ccouncil/Biology_124/Images/centralv
acoule.bmp
Animal Cell
Animal Cell
Food
vacuoles
(fv12, fv13,
fv14 and
contractile
vacuole (cv)
http://www5.pbrc.hawaii.edu/alle
n/ch19/01h-vor710401-28.html
EUKARYOTIC ORGANELLES
CELL WALL
★ In Plant and bacterial cells:
Composed of fibers made out of cellulose polysaccharide)
Cell walls in plants are thicker and stronger than those in bacteria
(which are primarily made out of protein polysaccharide)
Made up of a primary and secondary wall
Also present in fungi and some protists
Structure
Cell Wall
Description
In plant cells, outer layer of
cellulose; in bacteria, outer
layer of protein; also found in
fungi and some protists
Function
Protection and support
EUKARYOTIC ORGANELLES
CELL WALL
http://www.ibri.org/RRs/RR05
1/51cytoskeleton.gif
http://library.thinkquest.org/C0045
35/media/cell_wall.gif
http://www.learner.org/courses/essential/li
fe/images/show2.leaf.jpg
EUKARYOTIC ORGANELLES
CYTOPLASM / CYTOSOL
Clear, gelatinous fluid that fills the interior of the cell excluding
the nucleus
Contains sugars, amino acids and proteins that the cell uses to
carry out its everyday activities
Structure
Cytoplasm/Cytosol
Description
Clear, gelatinous fluid that
fills the inside of the cell
Function
Protection and support
EUKARYOTIC ORGANELLES
CYTOPLASM / CYTOSOL
http://www.ibri.org/RRs/RR05
1/51cytoskeleton.gif
http://www.cartoonstock.com/lowres/rjo0
896l.jpg
http://www2.puc.edu/Faculty/Gilbert_Muth/art0063.jpg
EUKARYOTIC ORGANELLES
RIBOSOMES
Sites of protein synthesis (where the cell produces proteins
according to the directions of DNA)
Consist of two subunits (small and large) composed of rRNA and
protein
The individual subunits are synthesized in the nucleolus and then
move through the nuclear pores to the cytoplasm, where they
assemble.
Structure
Ribosomes
Description
Small complex assemblies of
proteins and RNA, often
bound to endoplasmic
reticulum
Function
Sites of protein synthesis
EUKARYOTIC ORGANELLES
RIBOSOMES
http://www.ibri.org/RRs/RR05
1/51cytoskeleton.gif
http://www.estrellamountain.edu/faculty/farabee/biobk/BioBookCELL2.ht
ml#Ribosomes
(Both images)
CELL ANALOGIES
FACTORY
CELL ANALOGIES
FACTORY
THE CELL THEORY
Classical Theory:
Matthius Schleiden and Theodor Schwann (1838)
1. All organisms are composed of one or more cells.
2. The cell is the basic unit of structure and organization
of living things.
3. All cells come from pre-existing cells (through cell
division).
Modern Additions:
4. All cells contain hereditary information which is
passed from cell to cell during cell division.
5. All cells are basically the same in chemical
composition.
6. All energy flow (metabolism and biochemistry) of life
occurs within cells.