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The Cell in Its Environment
2
Transcript
The Cell in Its Environment
By Kayta Gheorghian
Active Transport
Diffusion
Osmosis
Diffusion
Osmosis occurs when water molecules diffuse through a selectively permerable membrane (such as a membrane.)
How does active transport differ from passive transport?
Is osmosis a form of actie transport or passive transport?
Why does diffusion occur?
In diffusion, molecules move from an area of higher concentration to an area of higher concentration to an area of lower concentration until they reach a point of equilibrium. Diffusion is an example of passie transport and it requires no energy.
Osmosis is a form of passive transport becuase it requries no energy.
The main difference between passive transport and active transport it that active transport requires energy while passive transport does not.
Diffusion occurs because molecules are always bumping into each other and moing from high to low concentration.
Active Transport
Examples of Diffusion
Why is osmosis such an important process for cells and all living things?
2 ways of active transport
Active transport is the movement of molecules across a cell membrane into a region of higher concentration.
- heat from foot to shoe
- air from inside to outside
- sunlight from outside to inside
- water spreading out across a patform
- die spreading out in water
- Cells cannot function properly without adeqate water.
- The mataboolism needs water.
- Osmosis helps maintain homeostasis.
- transport proteins - Transport proteins in the cell membrane 'pick up' molcules outside the cell and carry them in, using energy in the process.
Ways Osmosis can occur
2 ways of active transport
Is diffusion a form of active transport or passie transport?
Substances can move into and out of cells in 3 ways:
Diffusion is a form of passive transport because it doesn't use any energy.
- Water is moing out of the cell because there is more water inside the cell than in the surrounding liuid.
- Water is moing in/out of the cell because there is more/less water inside the cell than in the surrounding liuid. (dynamic equilibrium)
- Water is moing in to the cell because there is less water inside the cell than in the surrounding liuid.
- engulfing (phagcytosis) - The cell membrane surrounds particle. Once the particle is engulfed, the cell membrane pinches off and forms a vacuole within he cell, using energy in the process.
Sources
Into the center of which "cell" could the oxygen molecule diffuse the fastest (most efficiently)?
Why are cells so small?
Cell Membrane
- "Cells and Heredity" Science Explorer textbook; chapter 1
- class guided reading and notes
- www.google.com