Download Cell Organelles

Cell Organelles
Prokaryotic
• Do not have
structures
surrounded by
membranes
• Few internal
structures
• One-celled
organisms, Bacteria
http://library.thinkquest.org/C004535/prokaryotic_cells.html
Differences between Prokaryotic & Eukaryotic cells
Feature
Size
Genetic
material
Organelles
Prokaryote
Eukaryote
Small about 0.1 - 10.0
micrometres
From 10 to 100 micrometres
Circular DNA (in cytoplasm) and
small rings of DNA called plasmids
DNA in form of linear chromosomes
(in nucleus)
Few present, none membrane
bound
Many organelles:
•Double membranes e.g.: nucleus,
mitochondria & chloroplasts
•Single membrane e.g.: GA, ER &
lysosomes
Cell walls
Rigid formed from
glycoproteins (mainly murein)
•Fungi: rigid, formed from
polysaccharide, chitin.
•Plant: rigid, formed from
polysaccharides. E.g.: cellulose.
•Animals no cell wall
Cystoskeleton
Not present
Present
Cell Organelles
• Organelle= “little organ”
• Found only inside
eukaryotic cells
• All the stuff in between
the organelles is cytosol
(water and dissolved
substances)
• Everything in a cell
except the nucleus is
cytoplasm
Cell Membrane
• Boundary of the cell
• Made of a phospholipid bilayer
Nucleus
• Control center of the
cell
• Contains DNA
• Surrounded by a double
membrane
• Usually the easiest
organelle to see under a
microscope
• Usually one per cell
Cytoskeleton
• Acts as skeleton and
muscle
• Provides shape and
structure
• Helps move organelles
around the cell
• Made of three types of
filaments
Endoplasmic
Reticulum
• A.k.a. “ER”
• Connected to nuclear
membrane
• Highway of the cell
• Rough ER: studded with
ribosomes; it makes
proteins
• Smooth ER: no
ribosomes; it makes lipids
and it detoxifies
substances within the cell
Ribosome
• Site of protein synthesis
• Found attached to
rough ER or floating free
in cytosol
• Produced in a part of
the nucleus called the
nucleolus
That looks familiar…what is a
polypeptide?
Golgi Apparatus
• Looks like a stack of
plates
• Stores, modifies and
packages proteins
• Molecules transported
to and from the Golgi by
means of vesicles
(transport organelles)
Lysosomes
• Garbage recycling
centre/disposal of
the cell
• Contain digestive
enzymes that break
down wastes,
proteins and lipids
Which organelles do
lysosomes work with?
Mitochondria
• “Powerhouse of the
cell”
• Cellular respiration
occurs here to release
energy for the cell to
use
• Bound by a double
membrane
• Has its own strand of
DNA
Chloroplast
• Found only in plant cells
• Contains the green
pigment chlorophyll
• Site of food (glucose)
production
• Bound by a double
membrane
Cell Wall
• Found in plant and
bacterial cells
• Rigid, protective barrier
• Located outside of the
cell membrane
• Made of cellulose in
plants
• Extra protection for the
cell and provides rigidity
Vacuoles
• Large central vacuole
usually in plant cells
• Many smaller vacuoles
in animal cells
• Storage container for
water, food, enzymes,
wastes, pigments, etc.
Centrosome
• "microtubule organising
center”
• Made of a pair of
centrioles perpendicular
to one another
• Aids in cell division
• Usually found only in
animal cells
• Made of microtubules
Where else have we talked
about microtubules?
Cilia are thread-like projections of certain cells that beat in a
regular fashion to create currents that sweep materials
along;
Flagella may extend to the rear of a cell and push it
forward by snakelike wriggling, or stick out in front and
draw it along.
Each sperm cell is propelled by a trailing flagellum that
accelerates the little torpedo forward in its quest to
fertilise an egg.
Quick Review
• Which organelle is the control center of the cell?
Nucleus
• Which organelle holds the cell together?
Cell membrane
• Which organelles are not found in animal cells?
Cell wall, central vacuole, chloroplasts
• Which organelle helps plant cells make food?
Chloroplasts
• What does E.R. stand for?
Endoplasmic reticulum