Download CELL ORGANELLES

CELL ORGANELLES
Structures and Functions
PLASMA MEMBRANE
PLASMA MEMBRANE
STRUCTURE
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Phospholipid bilayer
Embedded proteins
Proteins on surface
Cholesterol molecules
within
PLASMA MEMBRANE
FUNCTIONS
• Boundary layer for the cell and certain
organelles
• “Gatekeeper:” allows only certain
molecules in or out if they are small
• Covers cell / keeps it different from the
environment
MEMBRANE LOCATIONS
• Cell Membrane
• Plastids – Vacuoles
• Golgi Bodies
• Endoplasmic Reticulum
• Mitochondria
• Nucleus
CYTOPLASM
FUNCTIONS:
• Holds organellles in
place, not too tightly
• Site of most cellular
chemical reactions
(metabolism)
• Gives shape to
animal cells
CYTOPLASM STRUCTURE
• “Chemical Soup”—Made of water (70%)
with many different dissolved solutes such
as fats, minerals, carbohydrates, proteins,
RNA
• Gel-like—Not quite as solid as jello, but
more viscous than water
RIBOSOMES
• Made of 2 “balls” of
RNA and protein
stuck together
• Numerous—may be
.5 million per cell
• Attached to rough
ER or floating in
cytoplasm
• No membrane
(Are they in prokaryotic
cells then?)
FUNCTION OF RIBOSOMES
• Site of Protein Synthesis
• Strings the amino acids together
ENDOPLASMIC RETICULUM
• Tube-like, branched
“canal system”
throughout the cell
• Continuous from nucleus
to cell membrane
• Half of plasma membrane
of cell is in ER
• Lumen: hollow portion
inside
FUNCTION OF ENDOPLASMIC
RETICULUM
• Transports newly made proteins to other
parts of the cell, or even out of the cell
• Divides the cytoplasm into reaction areas
• As it grows, it pushes out and inward to
form the cell / nuclear membrane
ROUGH ENDOPLASMIC
RETICULUM
• Has ribosomes
attached
• Membrane in “sheets”
or flattened sacs
SMOOTH ENDOPLASMIC
RETICULUM
• Mesh of
interconnecting
tubules smaller than
rough ER
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GOLGI APPARATUS
• Like a stack of hollow
pancakes
• Cisternae
(“pancakes”) are
slightly curved
• Vesicles come off
ends
• Abundant in cells that
secrete proteins (like
pancreas cells)
FUNCTION OF GOLGI
APPARATUS
• Modify and package cell products, like proteins
• Vesicles transport newly made proteins
MITOCHONDRIA
• Kidney bean shaped
• Double membrane:
inner is bigger than
outer, so has many
folds (cristae)
• Matrix full of fluid
• Numerous in cells
that require lots of
energy
FUNCTION OF
MITOCHONDRIA
• Powerhouse of the
cell
• Site of cellular
respiration—glucose
is broken down to
release energy as
ATP for cellular work
• Provides energy for
cell
• Can reproduce
themselves
Contain own DNA
and ribosomes
(An early cell?)
NUCLEUS
• Surrounded by a
nuclear membrane
(“skull”) that has
pores . Membrane is
double.
• Filled with gel-like
nucleoplasm
NUCLEUS
Contains:
• Nucleolus– a dense
area of RNA where
ribosomes are made
• Chromatin-- DNA
(genes) and protein
“Brain:” has recipe for
protein production
CHROMATIN IN NUCLEUS
• Chromatin is coiled
and packaged to fit
inside the nucleus
FUNCTION OF NUCLEUS
• Controls cell activities
• Keeps DNA out of the cytoplasm, but
allows RNA to move through the nuclear
pores and ribosomes
• Cell reproduction starts here
• Protein synthesis starts here: message
from DNA to ribosomes
CELL WALL
In plant cells only
• Cellulose fibers
• criss-crossed to form
a rigid box-like
structure
• Thick and porous
• Outside the cell
membrane
• Also found in fungi,
bacteria, some
Protista
FUNCTION OF CELL WALL
• Supports and gives
shape to plant cells
• Protects plant cells
from rupture
• Acts as fiber for
animals who eat
cellulose in cell wall
VACUOLES
• Come and go in animal
cells—also smaller and
more numerous
• Larger, less mobile in
plant cells—permanent,
too
• Filled with water and
solutes
• Plasma membrane on
outside
FUNCTION OF VACUOLES
• Store food, waste,
water, pigments,
toxins, et cetera
• Creates turger
pressure
PLASTIDS
• Found in plant cells, some Protista, some
Monera (blue-green algae)
• Types:
Chloroplasts
Chromoplasts
Amyloplasts
CHLOROPLASTS
• Outer membrane bag
filled with little stacks of
other sacs containing
chlorophyll, a green
molecule
• Site of photosynthesis
(CO2 + H2O made into
glucose using energy
from sun)
• Has own DNA
AMYLOPLASTS
• Filled with starch
instead of chlorophyll
• Clear
• Store energy for the
cell
Potato amyloplast
CHROMOPLASTS
• Have yellow or
orange pigments
instead of chlorophyll
• Give color to leaves
or vegetables-squash, sweet
potatoes, fall leaves
VESICLES
• Lysosome: responsible
for degrading proteins
and membranes in cell,
and materials ingested by
cell
• Peroxisome: produces
and degrades hydrogen
peroxide, a toxic
compound produced
during metabolism
Centriole
a small organelle near the nucleus of animal
cells only
used in cellular reproduction
• This has been brought to you by the cell
which would not be where it is today without
its organelles!