Notes
5.1 Passive Transport
Page 97
With your table:
1) Watch this video.
2) Answer these questions:
a) What is this organism?
b) What is the organism doing?
c) You know a little about the structure of cell
membranes. How is this possible?
Standards:
CLE 3210.1.5 - Compare different models to
explain the movement of materials into and
out of the cell.
SPI 3210.1.8 - Compare active and passive
transport.
RLE 2010.2.1 - Recognize the importance of
homeostasis as a survival mechanism.
Objectives (today I will…)
1. Analyze the importance of
homeostasis to an organism’s
survival
2. Differentiate the different types of
passive transport
3. Compare active and passive
transport
4. Explore factors that affect passive
transport
Homeostasis
•
Define homeostasis:
a relatively stable state of equilibrium or a tendency
toward such a state
•
Macro example:
•
Micro example:
We maintain a stable body temperature.
Cells use the cell membrane to regulate what comes in
and out of the cell to keep steady levels of nutrients,
water and other substances.
Cell Membrane Transport
•
Two main types of cell transport:
o
Passive:
the movement of substances across a cell membrane
without the use of energy.
o
Active:
the movement of chemical substances, usually across
a cell membrane that requires the use of energy.
Types of Passive Transport
(uses no energy)
•
Diffusion
Movement of solutes from an area of high concentration
to an area of lower concentration.
•
Osmosis
•
Facilitated Diffusion
Movement of water molecules from an area of high water
concentration to an area of lower water concentration.
Diffusion of molecules across a membrane through
channels and pores from an area of high concentration to
an area of lower concentration.
Concentration
Concentration:
the amount of a substance in a given volume
Two parts needed to determine concentration:
Solvent:
•
•
The substance in the greatest volume, it is what the solute is
dissolved in.
Solute:
The substance in the smaller volume, it is the substance(s)
that are dissolved in the solvent.
Concentration Example
Example: Salt water
Solvent? Water
Solute? Salt
•
•
Concentration Gradient
What is a gradient?
change in the value of a quantity (as temperature, pressure,
or concentration) with change in a given variable and
especially per unit distance in a specified direction
Passive Transport = High to Low
Why will things move from high concentration
to low concentration?
All molecules
are moving.
As they bump
into each other
they move faster
until there is
even space
between them.
Passive Transport = Equilibrium
Equilibrium:
When the
concentration of
molecules is the
same throughout
the space the
molecules
occupy.
Activity
Hanna– Can you smell the air
freshener?
How did that happen?
How does this affect cells?
Diffusion:
Solutes like oxygen, carbon dioxide, and other small
molecules can get in or out of the cell with no energy needed.
Osmosis:
Water can move freely in and out of the cell depending on its
environment. (Can be good or bad depending on the
environment.)
Video:
Watch the video and answer these
questions with your table.
1.Describe what you see happening to the
cells.
2. Relate this to the fact that the cell has a
permeable membrane.
Facilitated Diffusion (Passive)
Definition:
Diffusion of molecules across a membrane through
channels and pores from an area of high concentration to
an area of lower concentration.
Video - "Facilitated Diffusion”
Passive Transport Review:
Three types:
small solutes (O2 or CO2) moving across the
Diffusion: membrane
Osmosis: movement of water across the membrane
Facilitated diffusion: larger solutes (glucose)
•
•
•
moving across the membrane
through channels or pores
Common Characteristics:
Don't use any energy
Move from high to low concentration
•
•
Exit Ticket
(a 1/2 piece of paper)
•What is the difference between
regular and facilitated diffusion?