Cellular Process
- 2. Cellular Processes - Homeostasis
• Homeostasis is maintained on an individual level, by the semi-
permeable membrane surrounding the cell called the plasma
membrane.
• This membrane is made of a thin layer of long chained phospho -
lipids.
• Lipids are fats and the plasma membrane is semi-water repellent.
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- 3. Diffusion
• Molecules move across the cell membrane by a process called
diffusion.
• Diffusion is the movement of molecules from areas of greater
concentration to areas of lesser concentration.
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- 4. Diffusion
• Molecules move into or out of the cell
until there is an equal number on both
sides of the cell membrane.
• Water molecules are small enough to
pass through the cell membrane by
diffusion.
• Osmosis is the diffusion of water across
the cell membrane.
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- 6. Cellular Processes - Permeability
• The permeability of a membrane is the rate of passive
diffusion of molecules through the membrane.
• These molecules are known as permeant molecules
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- 7. Transportation of Molecules
• Larger molecules like sugars,
starches, and proteins sometimes
diffuse through protein channels.
Active Transport
• Active transport is a process that allows molecules to move across
the cell membrane from lower to higher concentrations.
• To do this requires energy.
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- 10. What is photosynthesis?
• Photosynthesis is a chemical reaction
that takes place in the chloroplasts of
plant cells.
• During photosynthesis, plants use the
energy of sunlight to produce energy-
rich molecules called carbohydrates
(ex. glucose).
In photosynthesis, plants take in carbon dioxide and
water and release glucose and oxygen wastes.
• Chloroplasts are where photosynthesis
occurs.
• Chloroplasts work much like solar cells
found in calculators.
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- 11. Chlorophyll
• A pigment is a molecule that absorbs
some colors of light and reflects
others.
• Chlorophyll is the main pigment used
in photosynthesis.
• Chlorophyll absorbs mostly blue and
red light, and reflects green light.
• This is why most plants look green.
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- 12. Cellular Respiration
• Cellular respiration is a chemical
reaction that occurs in all living things.
• Cells use oxygen and glucose to
produce carbon dioxide, water, and
energy.
• In most eukaryotic organisms,
cellular respiration takes place in
the mitochondria of cells.
• During cellular respiration, energy
is stored in a molecule called ATP
while some energy is released as
heat.
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- 14. Disposal of Wastes
• A living cell uses a number of
different chemical reactions to
survive.
• These processes create a large
amount of waste that the cell
needs to remove.
• This includes the byproducts of
reactions designed to burn energy,
as well as toxic metabolites such as
reactive oxygen species.
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- 15. The End
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