Cell Transport

1
Cell Transport

• How is material transported into and out of the
  cell?

2
Cell Transport in the Garden

• As you observe and illustrate your plants, think
  about how water and minerals enter the plant.
• Write you ideas on the space provided.

3
Class Activity

• Describe how we move through out the classroom.

4
Class Activity Recap

• The students moved from an area of high/low
  concentration or density to an area of high/low
  concentration until ________________________ is
  reached.

5
Cell Membrane

• The cell membrane regulates what substances can
  enter and exit the cell. It is referred to as
  selectively permeable.
• THINK! - What does selective mean?
• Very Choosy
• THINK! - What does permeable mean?
• To pass through
• Substances that can easily pass through the cell
  membrane are oxygen, carbon dioxide, and water.
  However, other substances such as salts and large
  sugar molecules can not easily pass through.
• Substances can move into and out of the cell by
  either passive transport or active transport.
  Passive transport does NOT require energy.
  Active transport requires energy.

6
Perfume Demo

• Raise your hand when you smell the perfume!
• THINK! - How were the people in the back of the
  room able to smell the perfume?

7
Food Dye Demo

• Observe the food coloring as it is dropped into
  the beaker of water.
• THINK! - What happened to the food coloring
  particles?

8
Passive Transport

• You just observed 2 examples of diffusion. Now,
  turn to your neighbor and try to define the term
  diffusion.
• Diffusion the movement of molecules from an area
  of HIGH concentration to an area of LOW
  concentration without using energy.
• The molecules will continue to move until they
  spread out evenly. This is called equilibrium.
• THINK! - Can you come up with any other examples?

9
Diffusion Animation

• Cells obtain certain particles through diffusion.
  For example, small oxygen molecules can easily
  pass through the cell membrane.
• Check out these 3 animations!!
• How Diffusion Works http//highered.mcgraw-hill.co
  m/sites/0072495855/student_view0/chapter2/animatio
  n__how_diffusion_works.html
• Perfume Diffusion http//www.biosci.ohiou.edu/intr
  obioslab/Bios170/diffusion/Diffusion.html
• Diffusion with arrows
• http//www.indiana.edu/phys215/lecture/lecnotes/
  diff.html

10
Lab Observations
Object Prediction for water Result for water Prediction for saltwater Results for saltwater
Raisin
Carrot
Potato
Gummy bear
Why did this happen?
11
Passive Transport

• Just like oxygen and other small particles can
  diffuse into and out of cells, water can also
  diffuse!!
• THINK! - Can you define osmosis?
• Osmosis the movement of water molecules from an
  area of HIGH concentration to an area of LOW
  concentration without using energy.
• The molecules of water will continue to move
  until they spread out evenly.

12
Raisin Demo

• THINK! - Using what you know about osmosis, what
  will happen to these raisins if I drop them in a
  beaker of water? Lets make a hypothesis!

13
Osmosis Problems

• Problem 1 A cell is placed in water that
  contains a little bit of salt. Therefore, the
  concentration of water is higher in the beaker
  compared to the inside the cell. Which way will
  the water flow?

ANSWER Water will flow into the cell the cell
will swell
14
Osmosis Problems

• Problem 2 A cell is floating in water that
  contains a lot of salt. Thus, the concentration
  of water in the beaker is low compared to the
  inside of the cell. Which way will the water
  flow?

ANSWER Water will flow out of the cell the cell
will shrink
15
Osmosis Problems

• Problem 3 A cell is floating in fresh water.
  Thus, the concentration of water in the beaker is
  the same as the concentration of water inside of
  the cell. Will water move into or out of the cell?

ANSWER Water molecules will flow into and out of
the cell at an equal rate the cell shape will
remain the same
16
How would you explain this cartoon using your
knowledge of osmosis?
17
Active Transport

• Active Transport the movement of particles from
  an area of LOW concentration to an area of HIGH
  concentration with the use of energy.
• Active Transport is like pedaling a bike uphill.
  Its takes a lot of energy.
• THINK! - How is active transport different from
  passive transport?
• Active transport requires energy while passive
  transport does not.
• LOW to HIGH

18
Osmosis in Elodea cells

• Fresh Water

• Salt Water