homeostasis and transport (part 2)
TRANSCRIPT
Biology I:
Homeostasis and Transport (Part 2)
Mr. Nettles
Agenda – Wed., Sept. 14, 2011
Warm-Up (3 min)
Today’s Objectives (2 min)
Lesson (40 min)
Wrap-Up (5 min)
Warm-Up1. When both sides of a concentration gradient
have an equal concentration of molecules on each side ______________ has been reached.
2. _________________involves the use a protein carrier to move molecules from an area of higher concentration to an area of lower concentration.
a) osmosis, b) diffusion, c) facilitated diffusion, d) active transport
3. In your own words, define homeostasis. (1 point Bonus!!) Explain an example related to the
human body.
Warm-Up1. When both sides of a concentration gradient
have an equal concentration of molecules on each side __equilibrium__ has been reached.
2. _________________involves the use a protein carrier to move molecules from an area of higher concentration to an area of lower concentration.
a) osmosis, b) diffusion, c) facilitated diffusion, d) active transport
3. In your own words, define homeostasis. (1 point Bonus!!) Explain an example related to the
human body.- the ability to maintain a stable internal (inside)
environment- People sweat to keep from overheating while exercising
Today’s Objectives
I will describe three types of passive transport.– Osmosis, Diffusion, Facilitated
Diffusion I will articulate one example of
active transport I will define: solvent, solute,
solution, hypertonic, hypotonic, and isotonic.
Think!!
If the molecules can’t get through the membrane, how else could it become less crowded?
Osmosis
Osmosis: WATER moves across a membrane to create more space.
Osmosis always moves water toward the side that has MORE molecules
Osmosis does NOT need energy.
Osmosis Osmosis moves WATER from higher
concentration [OF WATER] to lower concentration [OF WATER].
– Moves from more water to less water
Hypertonic vs. Hypotonic
Key Vocabulary Solute = what is being dissolved (salt,
Koolaid, other molecules) Solvent = what molecules are dissolved in
(water or other liquid) Solution = an even mixture of solute and
solvent (Koolaid drink) Hypertonic = high concentration of solute,
low concentration of solvent Isotonic = equal concentration of solute and
solvent Hypotonic = low concentration of solute, high
concentration of solvent
Hypertonic vs. Hypotonic If you place a normal cell in a
hypertonic solution, water will flow _?_ of the cell
If you place a normal cell in a hypotonic solution, water will flow _?_ the cell
Hypertonic vs. Hypotonic If you place a normal cell in a
hypertonic solution, water will flow OUT of the cell
If you place a normal cell in a hypotonic solution, water will flow INTO the cell
If water moves INTO a cell, the cell gets bigger = swells, expands, grows
- (Hypotonic solution)
If water moves OUT OF a cell, the cell gets smaller = shrinks
- (Hypertonic solution)
Active Transport
Using energy to move materials in and out of the cell is called active transport.
Molecules move from areas of low concentration to areas of high concentration.
– Move from less crowded to more crowded
Active Transport: Example: Na2+/K+ Pump
Sodium-Potassium Pump moves sodium out of the cell and potassium into the cell using energy.
Important for electric signal between neurons.
Moving Across a Membrane
Steps to tell what kind of transport:
1. Ask: what moves?– If molecules move , it is Diffusion.– If water moves, it is Osmosis.
Moving across a membrane2. Which way do the molecules
move?– If molecules move from higher
concentration to lower concentration, it is diffusion
– If molecules move from lower concentration to higher concentration, it is active transport.
Moving Across a Membrane
Osmosis Diffusion Active
What moves
Energy
Toward which side?
Example
Moving Across a Membrane
Osmosis Diffusion Active
What moves Water Molecules Molecules
Energy
Toward which side?
Example
Moving Across a Membrane
Osmosis Diffusion Active
What moves Water Molecules Molecules
Energy No No Yes
Toward which side?
Example
Moving Across a Membrane
Osmosis Diffusion Active
What moves Water Molecules Molecules
Energy No No Yes
Toward which side?
Water moves to the side with
more molecules
Molecules move to less concentrated
side
Molecules move to more concentrated
side
Example
Moving Across a Membrane
Osmosis Diffusion Active
What moves Water Molecules Molecules
Energy No No Yes
Toward which side?
Water moves to the side with
more molecules
Molecules move to less concentrated
side
Molecules move to more concentrated
side
ExampleCell in a
hypertonic solution
Smell of perfume
Na++/K+ pump
Wrap-Up If a cell that contains a 10% salt solution
is placed in a 90% salt solution, will water flow into or out of the cell? Is the cell hypertonic or hypotonic?
Identify the description as osmosis, diffusion, or active transport?1. Water moves into a cell from high
concentration to low concentration2. Iodine molecules move into a cell from high
concentration to low concentration3. Sodium molecules are moved from a low
concentration to a high concentration