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DO NOW
 Connect the dots using four straight lines without removing
your pen from the paper.
 Bonus challenge: can you do it using only 3 straight lines?
SOLUTIONS
UNIT TWO: BUILDING
BLOCKS OF LIFE
Active and
Passive
Transport
GOALS
 80% mastery of content
 80% mastery of lab material
 3 point increase on ACT
BOUNCERS AT A CONCERT…
 You are a bouncer at a concert
 You are a little bit shady.
 Some people can pay you to let them in, even if they don’t
have tickets.
QUESTION 1:
How much money would Beyonce and David
Beckham have to pay you to let them into
the concert?
QUESTION 2
How much money would these people have
to pay you to let them into the concert?
BOUNCERS AT A CONCERT…
 Cell membranes work the SAME way as bouncers
 Some cells can get in, some can’t
 This setup is called a SEMIPERMEABLE membrane
DIFFUSION: IN CONCERTS
 This is sneaking in the back door of the concert. There are NO
bouncers here!
 No cell membrane blocking movement of particles
 Requires NO energy from the bouncers (cell)
DIFFUSION: IN CELLS…
 EASY to do
 Movement of particles from an area of HIGH concentration to
an area of LOW concentration
 Requires no energy for the bouncers – it just happens.
 This is called
PASSIVE TRANSPORT
EXAMPLES OF DIFFUSION
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Perfume
Air in a tire
Oxygen across a cell membrane
Food coloring into water
Smells spreading from the oven to the rest of the house
PASSIVE TRANSPORT: OSMOSIS
 DIFFUSION of a substance through a SEMIPERMEABLE
membrane
 that’s the bouncer at the concert
 No extra energy is needed (like David Beckham)
 This is called PASSIVE TRANSPORT
 Examples
 Plant roots absorbing water
 Dipping a sponge in water
 When you soak your hands for a long
time and they start to look funny
ACTIVE TRANSPORT
 Some things take a extra ENERGY (or money) to get past the
cell membrane (bouncers)
 Moves against dif fusion
 This is a process called ACTIVE TRANSPORT
 Examples
 Moving in something we need (sugar)
 Push out waste (CO 2 )
IN PICTURES…
STOP AND JOT (2 MINUTES)
 Questions to write about…
 How do large particles, those too large to dif fuse, get into
cells?
 Do cells have mouths?
 Does swallowed food mix with directly with the other parts of
a cell?
LAB TIME
 You will be working with the people at your group
 Send one representative from your group to pick up…
 One plastic bag
 4 pieces of starburst
 DO NOT EAT THE STARBURST (yet!)
LAB TIME
 Your plastic bag is your cell membrane
 Your goal: to find a way to get the food INTO THE CELL
 Rules
 The candy must enter through a solid part of the bag.
 The inside of the bag may not be directly open to the external
environment.
 The candies entering the bag must remain clustered together.
 You may work with your hands in the bag in order to act as the inside
of a cell.
 The candy may be eaten only if it enters the bag "cell" under the
specified conditions.
 To qualify to EAT the starburst, your team must..
 1) solve the problem
 2) draw a picture of how it happens
SOLUTION?
 What does this mean about how food enters a cell?
 Is this passive or active transportation?