Day 13: Facilitated Diffusion/Active Transport ppt
Bellwork for today…
Write down
“Glued Lipids”
Standard B4.B: investigate and explain cellular processes, including homeostasis, energy conversions, transport of molecules, and synthesis of new molecules.
Essential Question: How are facilitated diffusion and active transport unique?
.
What is happening in the picture?
In the bellwork…
We discussed that molecules will
NATURALLY want to move/spread out from an area of HIGH concentration
to an area of LOW concentration.
concentration gradient: The range of concentrations over which molecules move during diffusion.
Concentration Gradient
Cell Membrane Recap
https://www.youtube.com/watch?v=LKN5sq5dtW
4&feature=youtu.be
https://www.youtube.com/watch?v=STLAJH7_zkY
&feature=youtu.be
EQUILIBRIUM: the concentration of a solute is the same throughout a system
particles continue to move
the goal of diffusion!
Diffusion does
NOT
require energy!!
The rate (speed) at which molecules pass through a membrane depends on its permeability.
PERMEABLE = all substances can pass through
IMPERMEABLE= no substances can pass through
Cell membranes are
SELECTIVELY permeable
Some substances can pass through, while others cannot
The lipid bilayer will allow most small molecules to diffuse in and out but not large or charged molecules.
So, if the cell needs these larger or charged molecules to function, how are they able to get through?
The Cell Membrane:
It’s not just Lipids, Ya’ll. It surrounds the entire cell and also contains special protein and carbohydrate compounds.
The Cell Membrane:
These proteins perform some very special functions for the cell.
The proteins form special pathways or channels for larger particles
Facilitated Diffusion: transport of molecules across a membrane using specific transport proteins.
Facilitate: to make easier or to assist
Diffuse: when molecules
move from high to low concentration or with the concentration gradient
High
Low
Facilitated Diffusion
Diffusion and Facilitated Diffusion both go with the concentration
gradient. (high to low)
Moving WITH the concentration gradient (high to low) requires no energy.
*Go with the flow
However...sometimes molecules need to move AGAINST the concentration gradient (Low to
High)
Moving from Low to High concentration DOES require energy…
*Going against the flow
Active Transport: movement of larger molecules through a protein channel into a region of higher concentration which requires energy.
ATP: Adenosine Triphosphate
Molecule that provides energy for Active Transport
Answer the following questions:
1. What is happening to the Hydrogen in the picture?
2. What process is happening in the top part of the picture? How do you know?
3. What process is happening in the bottom part of the picture? How do you know?
