Download - Cellular Process
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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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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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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© iTutor. 2000-2013. All Rights Reserved
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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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.© iTutor. 2000-2013. All Rights Reserved
Transportation of Molecules
• A cell can take in large particles of food by “engulfing” them.
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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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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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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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© iTutor. 2000-2013. All Rights Reserved
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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The End
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