Download Introduction to Organelles

Cytoplasm (cytosol): a cell's inner space
Plasma
membrane
Biology 11
A. Allen
Cytoskeleton
cytosol
Cytosol:
large fluid-filled space (mostly water + proteins that control most
of the cell metabolisms): glycolysis, transcription factors,
intracellular receptors etc.
Nucleus: a cell's center
Organelles
Function of the nucleus:
• Stores the chromosomes
(genetic material) Note:
Two kinds of genetic
material:
Reminder! Membrane-bound
organelles are only found in
eukaryotes.
•
•
•
•
Nucleus
Protein production machine: the ribosomes
Mitochondria and Chloroplasts
Endoplasmic Reticulum and the Golgi
apparatus
• Lysosomes and Peroxisomes
• Adapted and/or specialized for carrying out
one or more vital functions
...Nucleus: a cell's center
• Makes it easier to organize
DNA and to copy it before
parent cells divide into
daughter cells
• DNA replication and
synthesis of messenger
RNA (mRNA)
– deoxyribonucleic acid
(DNA)
– ribonucleic acid (RNA)
• Keeps the DNA molecules
of separated from
metabolic machinery of
cytoplasm.
Nucleolus
• Dense mass of
material in nucleus
• Cluster of DNA and
proteins
• Subunits must pass
through nuclear pores
to reach cytoplasm
• production of
ribosomes in nucleolus
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Nuclear Membrane (Envelope)
Chromatin
• Two outer membranes (lipid bilayers)
• Cell’s collection of DNA and associated proteins
• A chromosome is one DNA molecule and its
associated proteins
• Appearance changes as cell divides
• Pores span bilayer and controls what
enters/leaves nucleus.
Ribosomes
Endoplasmic Reticulum (ER)
FUNCTION:
• assembles proteins
• small spherical, black dots
• some are free in cytoplasm (cytoplasmic ribosomes), others are
attached to the ER (ER ribosomes)
…Endoplasmic Reticulum (ER)
STRUCTURE
• ER is a continuation of the outer nuclear membrane.
• Two types: Smooth and Rough. (Rough ER has ribosomes on it)
• Network of membrane that connects nuclear envelope to the cell
membrane
…Endoplasmic Reticulum (ER)
Endoplasmic Reticulum (ER)
FUNCTION:
• Smooth ER (no ribrosomes): responsible for lipid and membrane
protein modifications)
• Rough ER (has ribosomes on it) responsible for the synthesis of
other proteins). The ribosomes assemble the proteins within the
rough ER. Once assembled, the proteins pinch off the ER and are
released in a vesicle.
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Golgi Body (Golgi Apparatus)
…Golgi Body (Golgi Apparatus)
FUNCTION:
• processes, packages, and,
secretes cell products
(lipids & proteins)
• Put finishing touches on
proteins and lipids that
arrive from ER
• Package finished material
for shipment to final
destinations. (Exocytosis)
• Material arrives
and leaves in vesicles
Mitochondria
…Mitochondria
STRUCTURE
• Double membrane. Inner membrane is
folded for greater surface area. Folds
are called cristae.
• Interior is called the matrix.
• Contain their own genome (distinct
from nuclear genome)
• Self-replicating
The “powerhouse”
of the cell
FUNCTION
• ‘burns’ food, i.e. glucose to release
energy. Energy is used to make ATP.
ATP is a high-energy molecule that
can be directly used by the cell.
Lysosomes
STRUCTURE
• Formed by Golgi bodies
• Bound by a single membrane
Peroxisomes
•
•
•
•
Made by Golgi
Surrounded by a single membrane
Get rid of toxic substances
Many in the liver/ brain
FUNCTIONS
• Digests the food particles inside the cell with help of enzymes. These
enzymes work at low pH.
• Involved in autolysis (suicide of cell)
• Digest foreign bacteria that invade a cell
• Recycling of membrane components
• Repair damage to plasma membrane
lysosome
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Cell Wall
…Cell Wall
FUNCTION:
• maintains the shape of a
plant cell
• found in plants, some fungi,
some protists
• In plants, cell walls are made
of a polysaccharide called
cellulose.
• Structural component that
wraps around the plasma
membrane
Chloroplasts
Vacuole
• A large membrane bound sac
FUNCTION:
• Photosynthesis: converts sunlight, carbon dioxide,
and water into sugar (makes food for plants)
Cytoskeleton: a cell's scaffold
• very complex and dynamic cell component!
• organizes and maintains the cell's shape (e.g. epithelial cells of the
gut)
• anchors the organelles in place
• helps during the uptake of external material (endocytosis)
• involvement in cell movement
• growth
FUNCTION:
• storage area for proteins and
water
• Maintain structure in plant cells by means of turgor
pressure
...Cytoskeleton
intermediate
microtubules microfilaments filaments
tubulin
actin
keratin family
All help maintain cell shape
Cilia, flagella
Cytoplasmic streaming
Chromosome movement Pseudopodia
Organelle movement
Cell division
Nuclear lamina
Anchorage of
nucleus and some
other organelles
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...Cytoskeleton
...Cytoskeleton
...Cytoskeleton
...Cytoskeleton
Molecular
motors
Macrophage attacks bacteria
Microfilaments (actin) allow formation of pseudopods
...Cytoskeleton
...Cytoskeleton
Centrosome: Made up of centriole pairs
Striated Muscle
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Bibliography
• http://users.ipfw.edu/mustafaa/PQ_B10
0-02-ppt-Chapter4Cell%20Structures%20and%20Functio
ns.ppt
• http://images.google.ca/imgres?imgurl
=http://biology.dbs.umt.edu/biol101/la
bs/lab_6_images/sect05and02/cheek%
2520cell%25201000x.jpg&imgrefurl=
http://biology dbs umt edu/biol101/labs
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