Transcript Ch 7 - Cell Partsx

The Parts of the Cell
The Nucleus
The Nucleus
--nuclear envelope with nuclear pores and
nucleoplasm
-- chromatin --> chromosomes
--DNA remains in the nucleus, it sends instructions to
the cytoplasm via messenger RNA
--Nucleolus assembles ribosomes
Endoplasmic Reticulum -- Transport System
endoplasm means "within cytoplasm", reticulum
means "little net"
--divides cell into
compartments
--channels molecules
through the cell's
interior, like a little
highway
Rough ER
--has ribosomes which give it
its "rough" appearance
--functions in protein synthesis
--ER transports newly
assembled proteins to the
Golgi Apparatus
Smooth ER
--mostly contains enzymes that
unction in lipid synthesis (such
as hormones like estrogen and
testosterone)
Figure 4.10a
Golgi Apparatus -- Delivery System
--flattened stacks of
membranes
--functions in
collection, packaging
and distribution of
molecules made in the
cell and used
elsewhere
-- front end faces the
ER, and the back end
faces the cell
membrane
unprocessed proteins
enter the Golgi
apparatus from ER
proteins are packaged
and exported near
membrane
Jobs of the Golgi Apparatus
(aka Golgi Complex)
1. separates proteins
according to their
destinations
2. modifies proteins (adds
sugar and makes
glycoproteins)
3. packages materials into
vesicles which are exported
outside the cell - secretion
Lysosomes - Intracellular Digestion Centers
--vesicles that are used to
digest
--contain high levels of
degrading enzymes
(to "lyse" means to
dissolve)
--recycle old cell parts
--"suicide sac" - apoptosis
--digest other particles taken
in by phagocytosis
--found in animal cells
TAY-SACHS disease – missing an
enzyme of the lysosomes that breaks
down a fatty substance. Over time this
fat builds up in the brain and nervous
tissue, smothering the cells. Results in
degeneration and death.
Ribosomes - Sites of Protein Synthesis
--each is composed of
two subunits, one large
and one small
--mRNA is "read" by the
ribosomes and amino
acids are assembled into
proteins
--ribosomes are
manufactured by the
nucleolus inside the
nucleus
Other Organelles
-- Peroxisomes – result in
hydrogen peroxide, broken down
by catalase
-- Vacuole -- mainly storage or
specific functions (contractile
vacuole)
-- Plant cells have a CENTRAL
VACUOLE - used for storage
and help to maintain hydrostatic
pressure
ENERGY RELATED ORGANELLES
Mitochondria - The Cell's Chemical Furnaces
--contains its own DNA, support for Endosymbiosis Theory
--singular is "mitochondrion"
--2 membranes, one smooth outer membrane, and an inner
membrane folded into layers called cristae
--Cristae has two compartments: the matrix and the
intermembrane space
--mitochondria divide before
cell division, they are not
synthesized like other cell parts
--function to store energy for
cell use. Energy is stored in the
form of ATP - adenosine
triphosphate
Figure 4.17
Chloroplasts - Where Photosynthesis Takes Place
--only found in plant cells
--has its own DNA, like
mitochondrion
--functions to convert
light energy to
carbohydrates
--carbohydrates then
broken down in
mitochondria to produce
ATP
--consists of grana, closed compartments that are
stacked
--thylakoids are the individual disk shaped
compartments that make up the grana (stack of
thylakoids)
--stroma is the fluid surrounded the thylakoids
*Chloroplasts are a type of plastid
Chromoplasts – red, yellow and orange pigment
Leucoplasts – colorless (potatoes)
Cytoskeleton - Support System
Microfilaments (now called actin
filaments) – occur in bundles, form
tracks within the cell for the
movement of organelles, used to
form pseudopods (ameba)
Intermediate filaments - support
membrane, cell to cell junctions
Microtubules - (little pipe) –
regulated by the MTOC (microtubule
organizing center), radiate from the
centrosome - form the spindle
during cell division
Centrioles – used during cell division
to move and separate chromosomes,
only found in animal cell
Pseudopod – extensions of the cell that allow
for movement (ameba), depend on actin
filaments
Cilia (hair) & Flagella (whip)
--function in movement
Random Cell Images
and practice quiz
questions
Figure 4.6b
Figure 4.7a
Figure 4.7b
As seen through a Transmission Electron Microscope
Figure 4.12b
TAY SACHS
DISEASE
Figure 4.13
Figure 4.16
Figure 4.17a
Figure 4.18
Figure 4.19b
Mini Quiz
1. What part of the cell
produces vesicles for export?
2. What part of the cell makes
proteins?
3. What part of the cell
produces ATP?
4. What part of the cell
transports materials throughout
the cytoplasm?
5. What part of the cell has a
cis and a trans face?
a. ________________
b. ________________
c. _________________
d. _________________
e. _________________
f. __________________
f.
Figure 4.7b
Figure 4.10a
What is this structure?
What is this
structure?
Figure 4.11
Describe the processes
occurring in this image.
Figure 4.13
Figure 4.16b
What is this structure?
What is this structure?
What is its function?
Figure 4.19a
What is this structure?
Find the:
a. Nucleolus
b. Centriole
c. Vesicle
d. Smooth
ER
e. Lysosome
Watch the video. Can you name the cell
parts and processes shown?