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get your own table with organelle
dimensions
MEMBRANE PROCESSES
http://www.sciencemag.org/cgi/content/full/295/5560/1658
Membrane transport proteins (2003, enhanced
with links) http://www.sciencemag.org/cgi/content/full/301/5633/603
receptor
database: http://receptome.stanford.edu/HPMR/
also check molecular
biology links and organelles above
| PROCESS |
ENERGY SOURCE |
HOW IT HAPPENS |
WHAT MOVES this way |
Diffusion
|
Random molecular motion (passive) |
Dissolved substances become
evenly dispersed = net movement from areas of high concentration to areas of lower
concentration for each substance independently. Molecules move through membrane
faster when they're smaller and when the temperature rises.
http://pb010.anes.ucla.edu/diffusion.html
Brownian motion |
Small uncharged molecules, larger nonpolar molecules: Oxygen, ethanol, steroids, |
| Facilitated Diffusion and
Channel-mediated Diffusion |
__(fill it in)__ |
Like regular diffusion except ________(fill
it in)______
- Porin is a good example:
http://www.clunet.edu/BioDev/omm/porins/pormast.htm
- lots of other examples
http://www.biologie.uni-hamburg.de/lehre/bza/kanal/eporen.htm
- animations of channels:
spiral model voltage-gated:
http://www.utexas.edu/ftp/depts/pharmacology/gonzales/spiral.mov
ligand-gated: http://www.utexas.edu/ftp/depts/pharmacology/gonzales/l-g_ch.mov
- potassium channel
http://www.sciencemag.org/cgi/content/full/280/5360/69
2003 Nobel Prize in Chemistry
- Summary of types, with technical papers: http://www.its.caltech.edu/~lester/
- For more examples, see the ion channel pages (Note: some channels
are for active transport, below): http://phy025.lubb.ttuhsc.edu/Neely/ionchann.htm
- see your textbook
|
materials which fit carriers or channels:
Sugar, ions,__(fill it in)__ |
| Osmosis |
__(fill it in)__ |
Like regular diffusion except
________(fill it in)______
2003 Nobel Prize in chemistry:
http://www.sciencemag.org/cgi/content/full/302/5644/383/F4
mutations of aquaporin
http://www.jci.org/cgi/content-nw/full/109/11/1395/F3
aquaporin structure & animations of water flow
http://www.mpibpc.gwdg.de/abteilungen/071/bgroot
/presentations/aqp1_dyn/md_glpf.html
see
your textbook |
__(fill it in)_ |
| Active Transport |
Cell energy sources (usually ATP) |
Dissolved substances
become_______ dispersed
= net movement is often from areas of _____ concentration to areas of _________
concentration1. Important! See a cartoon animation at
http://rsb.info.nih.gov/NeuroChem/biomach/IONpmp.html
2 . co-transport see
http://www.sciencemag.org/cgi/content/full/301/5633/603 .
3. lots of other examples
http://www.biologie.uni-hamburg.de/lehre/bza/kanal/eporen.htm
4.
see your textbook
Case study: See CF |
_(fill it in)__
& ions
& |
| Endocytosis (active)
(phagocytosis) see text pp. 111b-113, 116 |
Cell energy sources, maybe like the
actin-ATPase example in the molecule
page |
Membrane surrounds and engulfs
substances, usually (maybe always) attached to receptors on external face
of membrane. _(fill in details)__ |
_(fill it in)__ |
| Exocytosis (active)
(secretion) |
_(fill it in)__ |
Reverse of endocytosis: _(fill
it in)__ latest research shows that even
"bulk" flow is specific and not "default"
see textbook figures
|
_(fill it in)__ |
download your own
membrane process table
MICROSCOPES
All about microscopes:
| |
(EYES, for comparison) |
LIGHT MICROSCOPES |
ELECTRON MICROSCOPES |
| Magnification |
1 |
>1000 X |
>100,000 X |
| Resolution = the smallest distance
between 2 objects |
10-4 m |
10-7 m; (limit of light
wavelengths, but computer-assisted video enhancement can sometimes get smaller) |
10-9 m usually, but.
theoretically as small as electron wavelengths: 10-12 m |
| Example of the smallest organelle visible |
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| HOW IT WORKS: source
focus
viewing |
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| ADVANTAGES |
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| DISADVANTAGES |
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SPECIAL TYPES
(optional) |
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dissecting polarizing |
Scanning: Transmission: |
"A cell is not just a bag of juice. It is
packed with solid structures, mazes of intricately folded membranes. There are about 100
million million cells in a human body, and the total area of membranous structure inside
one of us works out at more than 200 acres. That’s a respectable farm.
…. Much of the folded acreage is given over to chemical production lines, with moving
conveyor belts, hundreds of stages in cascade, each leading to the next in precisely
crafted sequences, the whole driven by fast-turning chemical cogwheels. The Krebs cycle,
the 9-toothed cogwheel that is largely responsible for making energy available to us,
turns over at up to 100 revolutions per second, duplicated thousands of times in every
cell. Chemical cogwheels of this particular marque are housed inside [guess what?], tiny
bodies that reproduce independently inside our cells like bacteria. As we shall see, it is
now widely accepted that [these tiny organelles] …. not only resemble bacteria but
are directly descended from ancestral bacteria who, a billion years ago, gave up their
freedom. Each one of us is a city of cells, and each cell a town of bacteria. You are a
giant megalopolis of bacteria."
Excerpted from Unweaving the Rainbow by
Richard Dawkins, Houghton Mifflin, 1998.
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