11-24 ATB

Start a new ATB Sheet – draw the
following

Then grab a book

Yes you can work with a partner
Read pages 97-102
 Pg 102  Answer questions #1-5
 Turn in at the end of the period

11-30 ATB

Why did you do poorly on the test?
12-1
What is the importance of the cell
membrane? What is it made up of?
 Today:

Look at grade sheet….what are you missing?
 Begin the new chapter dealing with cellular
transport

Homeostasis and Cell
Transport
Chapter 5

Diffusion –


the net movement of particles from an area
of higher concentration to an area of lower
concentration
Occurs because of the kinetic energy in
molecules (random movement)
DEMO

Diffusion in Water


EX: Food dye slowly diffuses b/c of the
movement of the water molecules and the
dye particles
Diffusion in air

EX: The odor molecules bounce against
each other and the gas molecules in the air
and slowly diffuse into the classroom.

Concentration Gradient –


difference in concentration
of molecules across a distance
Dynamic Equilibrium –


the condition in which there is continuous movement
but no overall change
This means there no longer is a concentration
gradient


there is no “high” and no “low” – everything is equal
Draw dynamic equilibrium in a glass with a solute…

Osmosis –
the diffusion of water molecules through a
selectively permeable membrane
 Diffusion of water goes from
high concentration to lower concentration


http://www.youtube.com/watch?v=sdiJtDRJQEc&feature=related
12-2 ATB
What is a concentration gradient?
 Today:


Describe a solution, a solvent and solute.
Where will the water move?
What will happen?

http://images.google.com/imgres?imgurl=http://w
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hl%3Den%26client%3Dfirefoxa%26rls%3Dorg.mozilla:enUS:official%26sa%3DN%26um%3D1
Where will
the water
move?
 Today:


Studying
the cell
membrane
using the
microviewers
12-3 ATB
12-6 ATB
Why can’t you see the nucleus of the red
blood cells (though you can see the
nucleus of the WBC’s)?
 Today:

Finish the microviewers
 Read though the procedure of the egg lab –
set the lab up

12-7 ATB
Why was the egg placed into the vinegar
in the lab? What were the bubbles that
formed? (look in your lab)
 Today:

Read over the egg lab
 Discuss hyper / hypo / isotonic solutions and
their effects on cells
 Take eggs out of vinegar…place into corn
syrup

Reverse Osmosis

Solution –


Homogeneous mixture (a uniform mixture) of two or
more substances
Example:


Solute:


Salt and Water
Substance that is dissolved in another substance
Solvent:


Thing that the solute is dissolved in
What is the most common solvent?

Water

Isotonic Solution –


a solution in which
the concentration of
solutes outside the
cell (ex: salts) is the
same as the
concentration of
solutes inside the cell
Does osmosis still occur in
this situation?
 YES. BUT, there
is no net change
in concentration
(water moving in and
out at an equal rate)

Hypotonic Solution –
solution in which the concentration of solutes
is LOWER than the solute concentration
inside the cell
Which way will the water move?
 into the cell  cell will swell / burst



Hypertonic Solution –

solution in which the concentration of solute is
higher outside than the concentration inside
the cell
 Which direction will the water move?
Out
of the cell
12-8 ATB
If a cell is placed in hypotonic
environment, what will happen to it? Why?
 Today:

Describe plasmolysis and the function of the
contractile vacuole in a cell
 Complete page 5 in the packet
 Continue the egg lab…place the eggs into the
distilled water


Quiz Friday
12-9 ATB
What is the function of a contractile
vacuole? Why don’t plants have one?
 Today:

Do the first page (front and back) of the
worksheet packet
 Finish the egg lab
 Go over the homework assignment
 Discuss plasmolysis
• Quiz tomorrow!!

12-10 ATB
What does hypertonic mean? Which
solution(s) were hypertonic in the lab?
 Today:



Quiz!
Labs due – turn them in
Osmosis in: Hypotonic,
Hypertonic, and Isotonic
Solutions
12-14 ATB
Describe dynamic equilibrium
 Today:

Review of hyper / hypo / isotonic solutions
 Discuss selective permeability and passive
transport
 Test  FRIDAY

Osmosis
and
Tonicity
Page 5 Questions








1. Look at the U-shaped tube in the figure. Why did the number of
water molecules on each side of the membrane change after
osmosis, whereas the number of sugar molecules stayed the same?
2. How does the plasma membrane of a cell compare with the
membrane in the U-shaped tube?
3. Explain the behavior of molecules in an isotonic solution.
4. Does osmosis occur if a cell is placed in an isotonic solution?
Explain.
5. Why does water enter a cell that is placed in a hypotonic solution
6. What happens to the turgor pressure inside a plant cell that is
placed in a hypertonic solution?
7. What can happen to animal cells exposed to hypotonic solutions?
What mechanism have some protests evolved for living in a
hypotonic environment?
8. What causes a plant to wilt?
Draw
Which way will the water move?
Cell
Sucrose = 25%
Water = 75%
Solution
Sucrose = 75%
Water = 25%
Cell
Sucrose = 65%
Water = 35%
Solution
Sucrose = 35%
Water = 65%
 Turgor
the pressure that exists inside a cell caused by water
High turgor pressure can cause animal cells to burst. Why?
 They do not have a cell wall.
What would happen if there is low turgor pressure in plants?
 Causes them to wilt
 Then you water the plant and it will regain the pressure
and stand up straight



Pressure –
 Contractile
 Organelle
Vacuoles –
that excretes excess water from
cells
Uses ATP
 Usually found in unicellular freshwater organisms.
 This prevents them from bursting in a hypotonic
solution.


Contractile vacuole
 Plasmolysis
–
 loss
of turgor pressure in plant cell
due to loss of water
 What happens to a plant during
plasmolysis?
The plant wilts
 The plants plasma membrane and cytoplasm
will shrink away from the cell wall

REVIEW:

What will happen to an Elodea Leaf in a
hypertonic solution?

Water will leave the cell…
 …which
is called playsmolsis, which will cause the
plant leaves to wilt

Review

If we put Elodea leaves in a hypotonic
solution, what happens?

Water will move into the cell….
 ….which
will cause the cell to swell. If it’s an
animal cell it will….
 …burst, UNLESS the cell has a
 Contractile vacuole to pump the water out. to
Summary of Hypo/Hypertonic solution
changes on a RBC.
Review




If the cell shrinks, it is in what type of solution?
If the cell is at equilibrium with it’s environment, its
in what type of solution?
If the cell swells, it’s in what type of solution?
Where will the water move in the examples below
Water –90%
Water 95%
Water 64%
Water 44%
Salt 5%
Salt 36%
Salt 56%
Salt – 10%
Water 50%
Water 50%
Salt 50%
Salt 50%
Starting
Mass
(grams)
Egg Lab Report

Graph



Must be colored
Graph your starting
mass and then use
your final mass data
which is in blue
Egg in
shell
Vinegar
Corn
Syrup
Distilled
“Percent Change in Mass”


Change
in mass
(g)
% Change in Mass
((Initial Mass – Final
Mass) / Initial Mass) x
100
Add a column to you data table:

Final
Mass
(g)
((Initial Mass – Final Mass) / Initial
Mass) x 100
Calculate all the changes in mass for
your egg
=====
====
===
Egg Lab Report

Analysis of your Data:



Be sure you are using the terms we’ve discussed in
class in your explanation of your results.
Example
What you should turn in:




Page 1 – Directions
Page 2 – Written lab report
Page 3 – Graph
Page 4 – Your actual lab procedure

Selective Permeability –


plasma membrane to allows some
materials to pass while keeping others out
Why is selective permeability important?

So the cell can allow important substance
in (water, oxygen, glucose) and keep
harmful substances out (bacteria).
Passive Transport

Passive Transport –

movement of particles across membranes by
diffusion
 This

process uses no ATP
Molecules moving from hi concentration  low
concentration
 Facilitated
Diffusion –
name for passive transport using transport proteins
 Does not use energy!!!
Example:




Glucose going from high concentration outside cell
low concentration inside the cell
Why doesn’t this need energy?

Because it’s still along the concentration gradient
Comparison: Diffusion vs.
Facilitated Diffusion
Diffusion

Where happen?

Particle type?
Facilitated Diffusion
12-15 ATB
What is facilitated diffusion? Why doesn’t
it require ATP?
 Today:

Describe ion channels
 Discuss active transport
 Pg 27 in worksheet packet

What is the process occurring in A?
What is the process in B?
They are both types of ____?(C)

Transport / carrier proteins –

proteins change shape to assist facilitated
diffusion

Ion channels or channel proteins –
 Protein channels that assist facilitated diffusion of
ions across the membrane
 Ions like Na+, Ca+, etc are not soluble in lipids,
so they must travel through proteins channels


Ion channels are ion specific
Some channels are always open, some have gate
 Gates open from stimuli: stretching of cell
membrane electrical or chemical signals
Channel vs. Carrier Protein
Which is the
channel
protein?
 Which is the
carrier protein?

Another example of channel
proteins
Active Transport

Active Transport –


transport of materials against a concentration
gradient – requires ATP
ATP (adenosine tri-phosphate) –



the ENERGY molecule for the cell
Breaks down from
ATP  ADP (Adenosine
di-phosphate)
Hydrolysis of the
phosphate releases
energy
Active Transport
Active Transport Example
http://www.youtube.com/watch?v=STzOiRqzzL4&feature=related



Sodium-potassium Pump – (transfer protein example)
 Protein that transfers Na+ out and K+ in
Creates electrical gradient which is important for
nerve impulses
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html
Na+ / K+ Pump

Endocytosis –


when a cell surrounds and takes in
material from the environment
Uses ATP
Endocytosis

Pinocytosis –

Transport of fluids into the cell

Phagocytosis –


Transfer of large particles / cells into the cell
Phagocytes –

Cells that ingest bacteria / viruses and
lysosomes fuse w/ vesicle to destroy them
before harm done

http://www.youtube.com/watch?v=1w10R9lv7eQ

Exocytosis –
when a cell expels materials to the
extracellular environment
 Cell exports proteins, hormones and wastes
this way
 This process uses ___ATP___

Endo / Exocytosis
Exocytosis and endocytosis
 http://www.youtube.com/watch?v=K7yku3
sa4Y8

The End
Warm Up 1-5

Draw and Label Each – hypotonic,
hypertonic, isotonic, active transport,
diffusion: (Blue circles = cells)
NaCl 25%
NaCl 35%
NaCl 12%
Sugar 5%
Sugar 10%
ATP used
NaCl 20%
Dialysis Tubing Lab
Groups of two or three (NOT 4)
 Read through part 1 – create a flow chart
of the procedure

Warm Up 1-6
How is the dialysis tubing “selective”?
 Get out your dialysis tubing lab.

Warm Up 1-6
Get you Part II lab set up
 Make your observations – finish lab
questions
 Turn in your lab.
 Today:


Begin photosynthesis chapter
Warm Up 1-7
Get your Part II lab set up
 Make your observations
 Finish the lab questions – Turn in Lab


Today:

Start Photosynthesis!!
Hypo / Hypertonic Solutions