Unit #3
Cellular Processes
Introduction
•The blue sections summarize key information and vocabulary
terms are underlined.
•Now that we know the basic parts of cells, how do cells get
the materials and create the energy needed to function?
•In this unit, WE will discuss:
– define homeostasis, or the process by which organisms
maintain a stable environment
– the forms of transport
– the creation of energy molecules during photosynthesis,
– and the release of cellular energy during cellular
respiration.
•
Concentrations
&
Cells
Cells have to move things in and out
of their membranes on a regular
basis (food, water, waste, etc.).
• The concentration in a solution
measures the amount of solute
(stuff in it, EX sugar in tea).
• Depending on the amount of
concentration, the molecules will
move accordingly.
• Video
http://universe-review.ca/I12-18-solution.jpg
Diffusion
http://www.okc.cc.ok.us/biologylabs/Image
s/Cells_Membranes/diffusion.gif
• In a solution, the particles are
moving constantly (in a glass
of water, molecules are still
moving).
• Molecules will always move
from a highly concentrated
(CROWDED) areas to the LESS
crowded areas.
• Diffusion is the movement of
particles to reach equilibrium
(the same or equal on all
sides).
• Sketch it!
Osmosis
http://www.okc.cc.ok.us/biologylabs/I
mages/Cells_Membranes/osmosis.gif
• Water is one of the most
important items that cells need
in order to function.
• Osmosis is the diffusion of
water through a selectively
permeable (to permeate is to
pass through) membrane.
• Selectively permeable means
that only certain things cross in
to and out of the cell.
• Water will move easily, until
the concentration is equal on
both sides of the cell
membrane.
• Hypotonic solution has a
higher concentration
inside the cell, so
molecules will travel in to
the cell (grow).
• An isotonic solution (or
“same strength”) is one
where the concentration
inside the cell matches the
outside of the cell – there
is little to no movement.
• Hypertonic solution has a
higher concentration
outside the cell, so
molecules will move out of
the cell and it will shrink.
Types of
Solutions
http://biology.unm.edu/ccouncil/Biology_124/I
mages/tonicity1.jpeg
http://2.bp.blogspot.com/_10M5kCPMTYM/S-1kTAlmmrI/AAAAAAAAABc/DucLSzYgyU/s1600/Bio+hypotonic,+Isotonic,+Hypertonic.gif
Hyp”O”tonic Solutions –
The cell gr”O”ws!
Hype”R”tonic Solutions –
The cell sh”R”inks!
I”S”otonic Solutions –
The “S”ame!
• Sketch the graphics (be sure to include the arrows
showing the movement of water!!!)
• Use the word memory tools to rember!
Passive Transport vs
Active Transport
http://www.daviddarling.info/images/
active_transport.jpg
• Diffusion and osmosis are processes within the cell that
occur naturally, without the need for energy (Passive).
• Protein channels: large proteins within the cell
membrane act as “doorways” to move molecules and
substances in and out of the cell (facilitated transport)
• Active transport is a process by which cells use energy to
move molecules against the concentration gradient .
• Simulation
Transport Cont.
• Endocytosis: the process when cells move shift the
cytoplasm to surround a substance; means “cell eating”
• Exocytosis: the process when cells expel (get rid of) material
through their membranes
• Video
http://static.howstuffworks.com/gif/ar
tificial-blood-8.jpg
Energy
• All life depends on energy, or the ability to do work, in order to
function.
• All cells are constantly using energy.
• The original source of all energy on Earth is the sun.
• Energy = in the chemical bonds of compounds such as
carbohydrates (sugars) and lipids (fats).
http://www.noaanews.noaa.gov/stories2005/images/s
un-soho011905-1919z.jpg
Photosynthesis
• Photosynthesis is the
process by which
autotrophs (plants and
some forms of bacteria)
convert light energy into
the energy of carbohydrates
(glucose).
http://static.howstuffworks.com/gif/irrigationphotosynthesis.gif
http://www.ap.stmarys.ca/~ishort/Images/Ear
th/Atmos/photosynthesis.jpg
Photosynthesis Cont.
• Remember that glucose (type of sugar) is a carbohydrate and
carbohydrates are biomolecules used for energy.
• Photosynthesis creates glucose using energy from the sun in
chloroplasts.
6CO2 + 6H2O + Sunlight = C6H12O6 + 6 O2
(Carbon Dioxide)
• Simulation
(Water)
(Energy)
(Glucose)
(Oxygen)
Chloroplasts
& Chlorophyll
• Chlorophyll is the green
pigment that absorbs light
energy from the sun.
http://botit.botany.wisc.edu/images/130/F
erns/Gametophyte_Images/Chloroplasts
_MC.low.jpg
Cellular Respiration
• Cellular respiration occurs in ALL CELLS, plants, animals, as
well as microscopic life, while photosynthesis occurs only in
some.
• Cell respiration occurs in the mitochondria.
• It releases energy from glucose and other food molecules in
the presence of oxygen.
C6H12O6 + 6O2 = 6H2O + 6CO2 + ATP
(Glucose)
(Oxygen)
(Water)
(Carbon Dioxide) (Energy)
http://www.learner.org/channel/workshops/sheddinglight
/images/photosynthesis.gif
A Comparison
Photosynthesis:
(Reactants)
(Products)
6 CO2 + 6 H2O + Energy = C6H12O6 + 6 O2
(Carbon Dioxide)
(Water)
(Glucose)
(Oxygen)
# of C = _____
# of H = _____
# of O = _____
Cellular Respiration:
(Reactants)
(Products)
C6H12O6 + 6O2 = 6CO2 + 6H2O + Energy (ATP)
(Glucose)
(Oxygen) (Carbon Dioxide) (Water)
# of C = _____
# of H = _____
# of O = _____
ATP = Energy
http://www.ustboniface.mb.c
a/cusb/abernier/Biologie/Mo
dule1/Images/atp.jpg
• Energy comes in many different forms, but our bodies use
chemical energy (found within the bonds of compounds) for
life’s processes.
• ATP is one of the most important compounds in the body
because it is used to store/release energy within the cell.
• Adenosine Tri Phosphate (ATP)
• Think of ATP as a fully
charged battery, ready to do
work for the cell.
• When the bonds in the
compound are broken in
ATP, energy is released.
• Observe the simulation;
breaking off one phosphate
creates ADP (Adenosine Di
Phosphate) and releases
energy to be used in the cell.
• Sketch it!
ATP Cont.
http://student.ccbcmd.edu/biotutorials/ener
gy/images/atp.gif
In Conclusion
• In this unit, we learned how cells move
materials in an out of cell membranes.
• Remember:
– Simple Diffusion = the movement of
particles from high concentrations to
low concentrations