Chapter 7 Notes:

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

Image: Richard Superfine

Lung Cilia

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!

• Blue whales have 80-100 quadrillion cells in their bodies.

= 50,000,000,000,000

= 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)