ORGANELLE
Nucleus (“library”)
LOCATION
Centralized
Chromosomes (“the
books”)
Prokaryotes  nucleoid
region
Eukaryotes nucleus
MEMBRANES
FUNCTIONS
Nuclear envelope =
1. Cell Regulation
double-membrane
2. Contains chromosomes
with nuclear pores,
which control what
goes in and out of
nucleus
1. “Parts List” – stores info
needed to build every
RNA in cell.
2. Passage of traits
In the nucleus
1. Ribosome synthesis
None
Ribosomes
1. Free in cytosol
2. Bound on ER
membrane
None
Chromatin – all the DNA
and associated proteins in
the nucleus.
Chromosomes – individual
strands of DNA and
associated proteins
(humans have 23 pairs).
None
Nucleolus
MISC
Free ribosomes – make
proteins that function in
cytosol
Bound ribosomes – make
proteins that will be exported
from the cell, inserted into the
cell membrane, packaged in
lysosomes, etc…
Bacteria typically only
have a single circular
chromosome.
-dense region of chromatin
(Ribosome RNA and
ribosomal protein genes)
-can produce 10,000
ribosomes/minute
Composed of two large
subunits that exist as
separate entities until
called upon to translate
mRNA into protein.
ENDOMEMBRANE SYSTEM – all the membranes within and surrounding the cell
ORGANELLE
LOCATION
MEMBRANE(S)
FUNCTION(s)
MISC.
Vesicles (“mailmen”)
Suspended in the cytosol,
attached to microtubules via
motor proteins like kinesin
Single
Transport vessels – the mailmen
of the cell
-carry cargo from place to place
within the cell
-carry cargo to the cell
membrane
Organelles that use them:
1. nuclear envelope
2. ER
3. Golgi
4. Lysosomes
5. Vacuoles
Endoplasmic Reticulum (ER)
-Throughout cytosol
-Continuous with outer nuclear
envelope
“
Single
See smooth and rough ER
Single
“
Single
1. site of lipid (fat,
steroid,phospholipid) synthesis
2. In the liver:
a. involved in glycogen storage
in the liver
b. contains enzymes involved in
drug detox in liver
3. In muscle – Calcium (Ca++)
storage
1. supplies more membrane for
other organelles and cell
membrane
2. Site of folding of membrane
proteins or proteins destined to
be secreted from the cell or
placed in another compartment
like the lysosome.
3. Site of glycosylation = attach
small polysaccharides to folded
proteins
4. Transport vesicles pinch off
Smooth ER
Rough ER
(“post office”)
Appear “smooth” because they
do not associate with ribosomes
-Appear rough due to association
with ribosomes.
MECHANISM
1. ribosome on ER synthesizes
polypeptide that threads into ER
2. Protein fold in ER
3. Protein may be modified –
glycosylated (short
polysaccharides added to
protein) to become glycoprotein
4. small portion of ER membrane
pinches off around proteins and a
vesicle is formed with proteins
inside.
ORGANELLE
Golgi (“central
receiving/sorting center”)
LOCATION
Near ER
MEMBRANE(S)
Single
-made of a series of
flattened membraneous
sacs
FUNCTION(S)
-stores and routes products
from the rough ER
-think of it as a sorting
center
-glycoproteins may be
chemically modified
(glycosylated = more
monosaccharides added, or
deglycosylated =
monosaccharides clipped
off)
MISC.
1. Receives deliveries on
the “receiving side”
2. Modifies the received
glycoproteins
3. Ships proteins to proper
destination from shipping
side.
4. The vesicles will go to
other organelles or the cell
membrane.
5. If vesicle fuses with cell
membrane, soluble cargo
(proteins) will be released
from the cell.
6. cis maturation model
Lysosomes (“recycling
facility”)
Cytosol (pH 7.2)
Single membrane,
maintain internal pH of 4.8
Intracellular digestion
-contains all major
hydrolytic (digestive)
enzymes.
-fuses with food vacuoles
taken up by phagocytosis
to break down food,
bacteria, viruses, etc…
-can also recycle cellular
material like old
mitochondria = autophagy.
You should be able to explain
how hydrolytic enzymes find
their way to the lysosome.
Lysosomal Storage Diseases
-hereditary
-involves impediment of a
lysosome enzyme (doesn’t
function properly or is
missing)
-results in build up of
indigestible material in
lysosomes
Ex 1) Pompe disease – lack a
glycogen digestive enzyme
(Alpha-glucosidase),
glycogen accumulates in
muscle fiber lysosomes
-
muscles weakening
fatal in childhood
Ex2) Tay Sachs – inactive
enzyme (hexosaminidase A)
that breaks down fatty acids,
resulting in a build up of fatty
acid in neurons
– nerve damage
- fatal in childhood
Vacuoles
Cytosol
Single
Variety of functions and
sizes:
1. Central Vacuole
– found in plants
- can act as a large lysosome
- can absorb water to increase
cell volume
-can store chemicals or waste
2. Contractile Vacuole
- collect excess water from
cell and expel it outside
-found in paramecium and
other freshwater protists
(video)
Generally larger than
vesicles
Peroxisomes
Cytosol
Single
- contains enzymes that
breakdown fatty acids (for
fuel or building material)
and other molecules.
-major product of many of
these reactions is hydrogen
peroxide (H2O2), which is
poisonous.
-contains the enzyme
catalase which catalyzes:
2H2O2  2H2O + O2
thereby eliminating the
hydrogen peroxide
ENERGY CONVERTING ORGANELLES
ORGANELLE
LOCATION
Mitochondrion
Cytosol
Chloroplasts
Cytosol
MEMBRANE(s)
Double
Many:
1. Outer mem.
2. Inner mem.
3. Lamellae
4. Thylakoid
FUNCTION(s)
Site of cellular
respiration (Krebs cycle
and ETC) – conversion
of unusable chem. PE
(sugars, fatty acids,
amino acids) to usable
chem. PE (ATP)
- site of photosynthesis
(converting the motion
of light into the motion
of electrons)
MISC.
Outer mem – “smooth”
Inner mem – convoluted
cristae
-Contains own circular
DNA
-Contains own ribosomes
that resemble bacterial
ribosomes
-self replicating
Fig. 4.16
Fig. 4.15
-light captured on
thylakoid membranes of
grana
-chem. reactions that
form food molecules
(glucose) occur in
stroma
-contains own circular
DNA
-contains own ribosomes
that resemble bacterial
ribosomes
-self replicating
CYTOSKELETON
ORGANELLE
LOCATION
MEMBRANE(S)
FUNCTION(S)
MISC.
Cytoskeleton
Cytosol
None
Composed of proteins
1. Microtubules
Cytosol
None
2. Microfilaments
Cytosol (predominantly
muscle cells)
None
3. Intermediate Filaments
Cytosol
None
-Cell support and structure
(skeleton)
-involved in cell
movement
-involved in vesicle
trafficking (the roadways
of the cell)
-Anchor organelles
-roadway for vesicles and
organelles
-important in movement of
cilia and flagella
-chromosome separation
during cell division
(mitosis and meiosis)
-muscle contraction
-cell shape
- microvilli structure
-amoeboid movement
- cyclosis
-cytokinesis (splitting cell
to complete division) –
cleavage furrow
-tension bearing
-anchor stationary
organelles especially
nucleus
-attach up with
desmosomes
-Thickest
-Hollow tube
- polymer of tubulin
dimers (two tubulin
proteins – alpha and beta)
-Thinnest
- polymer of actin proteins
-solid rods
-two polymers of actin
wrapped
-ropelike strands of fibrous
proteins (ex. Keratin)
-intermediate size b/w
microtubules and
microfilaments
-found in high
concentration in cells
under stress like skin