Chapter 7 Notes:
Parts of the Cell
Cell Factoid of the Day
How long do cells live?
• White blood cells typically live only 7-8
hours. That’s a short life!
• Red blood cells; a week
Cell Factoid of the Day
How long do cells live?
• Live bacteria have been found in Canada
that are over 500,000 years old. That’s a
looooong life!
Professor Eske Willerslev collecting soil samples in
the permafrost in the Yukon, Canada. Researchers
found half million year old bacteria in some of the
samples collected.
(Credit: Duane Froese, ScienceDaily Aug. 28, 2007)
Parts on the Outside
•
•
•
•
Cell membrane
Cell Wall (not on animal cells)
Cilia
Flagella
CELL MEMBRANE
• Boundary between cell and its external
environment
• Analogous to factory doors/windows, etc.
Two layers = lipid bilayer
CELL MEMBRANE
• Controls movement of materials (O2, H2O,
CO2, nutrients, waste) in and out of cell
CELL WALL (plants)
• Surrounds the cell membrane
• Adds strength and support to cell
• Analogous to factory walls, fence?
http://www.aber.ac.uk/gwydd-cym/graffeg/biolgell/cludiant/collenchyma.jpg
CILIA
• Short hairs on outside
of the cell
• Provide movement
• Analogous?? Move
the factory
Lung Cilia
Image: Richard Superfine
FLAGELLA
• Long, whip-like tail on the outside of a cell
• Moves the cell; Provides movement
Parts on the Inside
Cytoplasm, which contains…
• Nucleus (nuclear envelope, nucleolus,
chromatin)
• ER, Golgi Apparatus, Ribosomes
• Vacuoles, Lysosomes
• Chloroplasts, Mitochondria
• Cytoskeleton
CYTOPLASM
• Portion of the cell outside of the nucleus
• Jelly-like material suspends the other
organelles
• Analogous to factory air/open space
NUCLEUS
• Control center for eukaryotic cells
• Contains chromosomes
• Analogous to factory manager/boss office?
http://www.emc.maricopa.edu/faculty/farabee/
Cell Factoid of the Day
Not all eukaryotic cells have one nucleus…
• Red blood cells (erythrocytes) discard their
nuclei at maturity, which makes them
better at carrying oxygen to body tissues.
Cell Factoid of the Day
Not all eukaryotic cells have one nucleus…
• Skeletal muscle cells and plasmodial slime
molds have many nuclei within a single
cell membrane.
CHROMATIN
• DNA wrapped around proteins
• Makes up chromosomes: instructions to
run cell.
• Analogous to factory operating manual
Uncondensed Chromosome
Condensed Chromosome
NUCLEAR ENVELOPE
• Boundary between nucleus and cytoplasm
• Contains pores (holes) for materials to
pass in/out
• Analogous to factory managers office?
http://acs.lbl.gov/ImgLib/
http://elliottcelltour.com/files/QuickSiteImages/Nucleus.jpg
Cell Factoid of the Day:
• Humans have about 50 trillion cells in their
bodies! = 50,000,000,000,000
• Blue whales have 80-100 quadrillion cells
in their bodies.
= 100,000,000,000,000,000!
NUCLEOLUS
• Produces the RNA that makes up
ribosomes
• Analogous to factory: instructions to build
factory robots or assembly line tools
Photos by Mr. Stephens
RIBOSOMES
• Site where proteins are made (protein
synthesis)
• In cytoplasm or on rough ER
• Analogous to assembly line robots which
build what the factory makes
http://pbs.org
ENDOPLASMIC RETICULUM (ER)
• Folded membrane, which connects
nucleus to cell membrane
• Site for assembly and transport of proteins
• Analogous to factory conveyor belts?
ENDOPLASMIC RETICULUM (ER)
• ROUGH ER; w/ ribosomes
• SMOOTH ER; no ribosomes; special tasks
GOLGI APPARATUS
• Packages and ships proteins out of or
inside the cell
• Shipping dept?
http://www.ncbi.nlm.nih.gov/
http://kvhs.nbed.nb.ca/
https://www.msu.edu/~lupalisa/
LYSOSOMES
• Membrane-bound sac with digestive
enzymes inside
• Digests: worn-out organelles, food,
bacteria/viruses;clean up messes/ recycle
• Analogous: Clean up crew
http://www.medicine.mcgill.ca/dynhist/
VACUOLES
• Storage sac for: food, enzymes, water,
wastes, etc…
• Analogous to factory inventory room?
http://faculty.plattsburgh.edu/jose.deondarza/
http://www.bio.miami.edu/~cmallery/
MITOCHONDRIA
• Produces energy for the cell
• Breaks sugars (glucose) down for energy
(ATP)
• Analogous to factory power plant?
http://porpax.bio.miami.edu/~cmallery/150/makeatp/makeatp.htm
CHLOROPLASTS (plants)
• Performs photosynthesis
• Converts energy from light to create
sugars and starches; food for plant.
• Analogous to factory break room?
CHLOROPLASTS (plants)
• Green because of pigment called
“chlorophyll”
Photosynthetic Sea slugs
http://www.seaslugforum.net/
MICROTUBULES
• Cytoskeleton
• Provides support for organelles and
maintain cell shape; used in cell division
• Analogous to factory internal walls?
http://elliottcelltour.com/
MICROFILAMENTS
• Make up part of Cytoskeleton
• Provides internal support for cell
http://elliottcelltour.com/
http://tools.invitrogen.com/
CENTRIOLES
• Cytoskeleton (made of microtubules)
• Coordinate cell division (absent in most
plant cells)