Ch 3 Cells:
WebAssignment
Name __________________
Date ___________________
Print a copy of this assignments and answer the
questions as you visit each site. PRESS CTRL &
CLICK ON EACH HYPERLINK TO EASILY ACCESS
EACH WEBSITE
Objective
You will (A) compare the size of different objects, (B) distinguish between
animal and plant cells, (C) explore cell membrane characteristics (D)
solutions and (E) compare passive and active transport.
Go to www.cellsalive.com
Navigating the Site
Cells Alive has a navigation bar at the left. After accessing the page, click
on CELL BIOLOGY on the left side navigation bar. From here you will
navigate links: “How Big is a...”, and “Cell Models”.
Part A. “HOW BIG IS A...”
Here you will look at objects found on the head of a pin. Your job is to rank
them in order of size on the chart below and estimate the length of each (in
nanometers, micrometers, or millimeters). The line in the bottom right
corner of the screen is used to help you estimate. Sketch each of these
objects.
Keep this in mind as you view
 A meter (M) is about the distance from the tip of your nose to the
end of your hand (1 meter = 3.28 feet).
 A millimeter (mm) is one thousandth of a meter or 1/10 of a cm.
 A micron or micrometer (µm) is a millionth of a meter, or 1/1000 of a
mm, which is the scale that is relevant to - for instance - building
computers, computer memory, and logic devices.
 A nanometer is a billionth of a meter or 1 millionth of a mm. That’s
pretty small!
 1 inch = 25,400,000 nanometers
 The smallest atoms are 1/20,000 of a µm (2 angstrom)
WOW? Does your brain hurt yet?
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Object
Sketch
Size in nanometers,
micrometers, or millimeters
Human Hair
Dust Mite
Pollen
Red Blood Cells
E. Coli
Staphylococcus
Ebola Virus
Rhinovirus
Part B. Cell Models
Take some time to look at the animal and plant cells at this site in order to
notice the differences. Click on each part of the animal cell. What two
parts are not found in animal cells but are found in plant cells?
1.
2.
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Go To: www.wisc-online.com/objects/index_tj.asp?objID=AP1101
Cell membranes
Watch the complete animation and take the small quizzes along the way.
1. List all the parts of the membrane and give their function.
2. Draw a simple diagram of cell membranes below. Label each
component as well as the hydrophobic and hydrophilic ends of the
lipids.
Stop here and read pgs. 87-93 in your textbook.
1. Give the simple and detailed definition of homeostasis (p 87):
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“All cells are in solution. One of the most critical influences upon the
existence of a cell is the concentration of the substances in the solution
around it. The plasma membrane is the structure that stands between the
surrounding environment and the cell, working to maintain homeostasis.”
(Biology for Christian Schools, p 88)
Go to : http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_diffu
sion_works.html
Watch the excellent animation here and answer the following:
1. Define diffusion-
2. What conditions affect the rate of diffusion
Go to : http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_osmo
sis_works.html
1. Define osmosis:
Now go to
http://www.mrphome.net/mrp/Membrane_Transport.html
Part D. Solutions and Membrane Transport
Scroll down the page and watch each animation. After reviewing the terms
OSMOSIS and DIFFUSION observe each animation and define the
following:
1. Hypotonic solutionhypo meansExplain might happen to a cell in a hypotonic solution- ______________
____________________________________- this is called cytolysis.
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2. hypertonic solutionhyper meansExplain what might to a cell in a hypertonic solution- _______________
___________________________________- this is called plasmolysis.
3. isotonic solutioniso meansExplain what happens to a cell in an isotonic solution- _______________
_________________________________- this is called equilibrium.
You have been exploring how things are transported across cell membranes.
There are two types of transport- Passive Transport and Active Transport.
Both diffusion and osmosis are examples of passive transport.
Go to
www.northland.cc.mn.us/biology/Biology1111/animations/t
ransport1.html
Part E. Passive and Active Transport
Watch the animation in its entirety. Give a simple definition of passive and
active transport. List the examples of each type of transport and describe
each one.
4. passive transportExamples are :
5. active transportExamples are:
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