Download CONNECT! - Thousand Islands CSD / Homepage

CONNECT!
Imagine you are trudging home from
school on a cold, wintry day. When you
finally arrive, you enter a room where
you are sheltered from the wind and
surrounded by a warm, comfortable
environment. Your house is a
controlled environment just like the
cells in your body. Similar to the way
the walls of your home act as a barrier
against the elements, the cell
membrane provides a barrier between
the internal components of a cell and its
external environment.
Cell organelles are tiny structures
inside cells that do jobs for the cell.
1. Plasma Membrane (Cell Membrane)
• made of a double lipid layer in which large
proteins float
• transports materials into and out of the cell: this
is called intercellular transport
• recognizes and responds to chemical messages
receptor
Transport In and Out of the Cell
• For a cell to survive, some materials, such
as water, oxygen, and nutrients must pass
through the membrane and into the cell.
Other materials, such as CO2, must pass
out of the cell.
• Molecules either enter or leave a cell
through diffusion or active transport.
Diffusion
• Molecules tend to move naturally from an
area of high concentration to an area of
low concentration
Here the molecules move
through the liquid by
diffusion.
Here the
molecules move
out of the liquid
and into the air
by diffusion.
• Diffusion can occur across cell membranes.
• Diffusion requires no energy from the cell, since
it occurs due to molecular movement.
• When some organisms digest food, they
are changing it from large complex
molecules to simple small molecules. This
change in size allows our food to become
small enough to pass through the cell
membrane. Once nutrients enter the cell
they are used to build larger molecules
(synthesis) or broken down further to
release energy (cellular respiration).
Click on image below
to view video clip
Size matters!
• larger molecules such as starch, proteins,
and lipids cannot fit, because they are too
big
Inhaled oxygen
is in higher
concentration
in alveolus of
lung than in
blood capillary,
so it diffuses
out of the lung
into the
capillary into
the red blood
cells.
CO2 is in higher
concentration in
red blood cells
than in alveolus
of lung, so it
diffuses out of
the RBC into the
capillary into the
lung, and is
exhaled.
Chunk!
•
•
•
•
•
•
•
•
•
•
•
•
What does “organelle” mean?
What is the cell membrane composed of?
What molecules move into and out of cells?
Define diffusion.
Does it require energy?
Why does diffusion occur?
What determines if a molecule can cross a cell membrane?
What does “passive transport” mean?
Name some specific molecules that enter by diffusion.
Name some specific molecules that can’t.
Explain diffusion in the lung.
Explain diffusion in the digestive tract.
• What is going into the respiring cells?
• What is coming out of the respiring cells?
• What are the pink organelles?
• What process is involved in the molecules entering and exiting the blood
cells and the respiring cells?
• What is diffusing in each direction? Why?
That’s all, folks!
Sources of Images
•
•
•
•
•
•
•
•
•
•
•
•
Snowboard – http://improved.ipower.com/images/snowboard.gif
Unlabeled cell - library.thinkquest.org/.../cell-wall.gif
RED BOUNCING MOLECULES - http://edtech.clas.pdx.edu/osmosis_tutorial/diffusion1.html
Black/white cell membrane http://upload.wikimedia.org/wikibooks/en/1/1a/Anatomy_and_physiology_of_animals_structure_pl
asma_membrane.jpg
Cell membrane - library.thinkquest.org/.../cell_membranes.html
Diffusion animations - http://leavingbio.net/OSMOSIS%20AND%20DIFFUSION_files/image003.gif
Liquid diffusion - http://commons.wikimedia.org/wiki/File:Diffusion.gif
Across membrane - http://www.blobs.org/science/chemistry/diffusion2.gif
Capillary http://www.scifly.co.uk/client_files/AQA%20Additional%20Science/diffusion_into_capillary_3.jpg
Lung - http://www.scifly.co.uk/higher-tier/c/562/i/2173/?uid=201001291652197818168
Winter house - http://caaneo.ca/about/blog/wp-content/uploads/2008/01/winter-house.jpg
Pig - <a href="http://www.greatfunnypictures.com/browse.asp?id=118"><img
src="http://www.greatfunnypictures.com/pictures/117_hehe.jpg" border="0" alt="Funny Pig Funny Pictures"></a>