3.2 cell organelles key concept eukaryotic cells share many similarities
TRANSCRIPT
3.2 Cell Organelles
KEY CONCEPT Eukaryotic cells share many similarities.
3.2 Cell Organelles
Cells have boundaries
The Plasma Membrane
• Forms a boundary
between a cell and the
outside environment
• Controls the passage of
materials into and out of
the cell
• Helps to maintain
homeostasis
3.2 Cell Organelles
Cells have boundaries
Water
Inside the Cell
Outside the Cell
Oxygen
Wastes
CO2
Glucose
WastesInvaders
• The plasma membrane is selectively permeable
- allows some, but not all materials to cross
3.2 Cell Organelles
Cells have boundaries
Structure of the Plasma Membrane
• Composed of a phospholipid bilayer
3.2 Cell Organelles
Cells have boundariesOther components in the Plasma Membrane
Proteins
• some span the entire membrane and help materials cross
• others are found on the inner and outer surface – anchoring
3.2 Cell Organelles
Cells have boundariesOther components in the Plasma Membrane
• Cholesterol – strengthen the membrane
• Carbohydrates – cell identification
3.2 Cell Organelles
Cells have boundaries
• The Plasma membrane is referred as the fluid mosaic model
*Fluid - flexible
*Mosaic - pattern
3.2 Cell Organelles
Cells have boundaries
The Cell Wall• A rigid structure located
just outside of the plasma
membrane
• Found in plants, fungi, most
bacteria, and some protists
• Provides protection and
support
• It is not selectively permeable
• In plants, it is composed of
cellulose
3.2 Cell Organelles
Cells have an internal structure.
The Cytoskeleton
- A network of protein fibers that crisscross the entire cell
- Three types of fibers
a) Microtubules
b) Intermediate filaments
c) Microfilaments
3.2 Cell Organelles
Cells have an internal structure.• The cytoskeleton has many functions.
– supports and shapes cell– helps position and transport organelles– provides strength– assists in cell division– aids in cell movement
3.2 Cell Organelles
Cells have an internal structure.
The Cytoplasm
-Fills the space between the nucleus and cell membrane
-Consists of organelles and cytosol(mostly water)
3.2 Cell Organelles
Several organelles are involved in making and processing proteins.
The Nucleus
• Storehouse of DNA
• Surrounded by a nuclear
membrane
• Nuclear pores allow large
molecules to pass
between the nucleus and
the cytoplasm
• The nucleolus is where
ribosomes are produced
3.2 Cell Organelles
Several organelles are involved in making and processing proteins.
The Endoplasmic Reticulum
• An interconnected network of folded membranes
• Important in synthesis and transport of cellular materials
• Two types – Rough ER and Smooth ER
3.2 Cell Organelles
Several organelles are involved in making and processing proteins.
Rough Endoplasmic Reticulum
• Has ribosomes attached
• Proteins are made by the
ribosomes on the
surface, and then
move inside the rough ER
to be packaged into a
vesicle
• The vesicle then takes
the protein to the Golgi
Apparatus
3.2 Cell Organelles
Several organelles are involved in making and processing proteins.
Ribosomes
• The site of protein
synthesis
• Can be found attached
to Rough ER or free in
the cytoplasm
3.2 Cell Organelles
Several organelles are involved in making and processing proteins.
Smooth Endoplasmic Reticulum
• No ribosomes attached
• Produces lipids
• Detoxification of drugs
and poisons
3.2 Cell Organelles
Several organelles are involved in making and processing proteins.
The Golgi Apparatus
• Closely layered stacks
of membrane – enclosed
spaces
• Modifies, packages, and
transports proteins
• The vesicles can then
be stored, transported,
or secreted
3.2 Cell Organelles
Some organelles transform energy in the cell
Mitochondria
• Bean shaped organelle
with a double membrane
• Produces ATP through
cellular respiration
• The cell uses the ATP for
energy
• Mitochondria have their
own ribosomes and DNA
C6H12O6 + 6 O2 = 6 CO2 + 6 H2O + ATP
3.2 Cell Organelles
Some organelles transform energy in the cell
The Chloroplast
• Organelles that carry out
photosynthesis
• Found in plant cells
• Has two membranes
• Contains chlorophyll
which absorbs light and
gives plants their green
color
• Also have their own DNA
and ribosomes6 CO2 + 6 H2O + Light = C6H12O6 + 6 O2
3.2 Cell Organelles
Other organelles have various functions.
Vacuoles
• A membrane bound sac used for storage
Ex – water, food molecules, and enzymes
• Plant cells have
one large vacuole
• Animal cells have
many small vacuoles
3.2 Cell Organelles
Other organelles have various functions.
The Lysosome• Membrane bound organelle
that contains digestive
enzymes
• Digests worn out organelles,
food particles, and engulfed
viruses or bacteria
• Numerous in animal cells
• Their presence in plant cells
is still questioned by some
scientists
3.2 Cell Organelles
Other organelles have various functions.
Centrosome and Centrioles
• The centrosome is a small
region of the cytoplasm that
produces microtubules
• In animals, it contains a pair
of centrioles
• Centrioles help DNA divide
during cell division
3.2 Cell Organelles
Other organelles have various functions.
Cilia Flagella• Short, numerous hair-like
projections
• Move in a wave-like motion
• Used for feeding and
locomotion
• Long projection
• Moves in a whip-like motion
• Used for locomotion