Unit 3 Movement Through The cell. Plasma Membrane/Cell Membrane Why is the cell membrane important? Selectively Permeable : A membrane that allows some

Unit 3

Movement Through The cell

Plasma Membrane/Cell Membrane

Why is the cell membrane important?Selectively Permeable: A membrane that

allows some substances to pass through while keeping others out.

The cell membrane is like a Fish net…lets water in and out, but keeps the fish in


Why is the cell membrane important?Cell Membrane: Flexible, selectively

permeable boundary that helps control what enters and leaves the cell.


What are the 2 main parts of the cell membrane?

1. Phospholipid bilayer: 2 layers of lipids (fat)


What are the 2 main parts of the cell membrane?

2. Protein pump/channel: Proteins that help move large materials across the cell membrane

HomeostasisWhat is homeostasis?

Homeostasis: Regulation of an organism’s internal environment to maintain conditions needed for life.

Running increases body temperature

Panting decreases body temperature


If you sweat, you lose water….

You get dehydrated….

You are not in homeostasis!

If you drink water, and replace water levels…

You feel good…

You ARE in homeostasis!


If you have a fever….

You don’t feel good….


If you don’t have a fever…

You feel good…

You ARE in homeostasis!


If your sugar is too high….

The blood is like syrup…too thick…

Blood can’t flow…you don’t feel good….


If your sugar level is normal…

Blood can flow…you feel good…

You ARE back in homeostasis!

Diabetics can’t regulate sugar levels

Insulin Shots lower sugar levels

Clicker Question #1

A cell membrane is like a window screen because:

a. it provides support

b. it prevents water from entering

c. it controls what enters & leaves the cell

d. it prevents everything from leaving

Clicker Question #2

These allow larger substances to move into and out of the cell membrane:

a. Lipids b. Phospholipid bilayer c. Carbohydrate pumps d. Protein pumps

Clicker Question #3

This is another name for the cell membrane:

a. Nucleus b. Phospholipid bilayer c. Homeostasis d. Protein pump

Clicker Question #4

What is a word that can be associated with “homeostasis”?

a. Balance b. Unbalance c. Fluctuate d. Unstable

Review….Solute: Any substance (like salt) that is

dissolved in water is a solute.

Solution: The combination of a solute (salt) and solvent (water).

Example: salt in water = saltwater

Concentration: Of a solution is the mass of solute in

a given volume of solution.

Concentration just means how salty the water is

Nature wants to be balanced!

One of the most important functions of the cell membrane is to regulate the movement of molecules from one side of the membrane to the other.

Remember…

Passive Transport

Passive Transport: The movement of molecules from an area of high concentration to an area of low concentration WITHOUT the use of energy.

There are 2 Types of Passive Transporta. Diffusionb. Facilitated Transport

The next several slides are about the transport of molecules across the cell membrane that does NOT require ENERGY

What are the types of movement through the membrane?

Diffusion is a type of movement of molecules through the cell membrane where the molecules move from an area of HIGHER concentration to an area of LESSER concentration.

Example: Like moving from the city to the country

Higher

Concentration

LowerConcentration

Diffusion causes many substances to move across a cell membrane but does NOT require the cell to use energy.

What is Diffusion?

Diffusion tries to get the solute molecules to be equal on each side of the membrane.

When both sides of the membrane are equal in terms of solute, the cell is in

equilibrium.

All cells try to attain equilibrium (BALANCE)!

Osmosis & DiffusionThe sound & video does not always match up…you

don’t have to point this out!...I know.

What are the types of movement through the membrane?

If a substance is able to diffuse across a membrane, the membrane is permeable to that substance.

Example: A sponge is permeable.

Most cell membranes are selectively permeable which means that some substances can pass across easily and others cannot.

Clicker Question #5

Salt is an example of a(n): ____

a. Solvent b. Solute c. Solution d. All of the above

Clicker Question #6Type of movement of molecules through the cell

membrane where the molecules move from an area of HIGHER concentration to an area of LESSER

concentration.

a. Diffusion b. Homeostasis c. Photosynthesis d. Active transport

Clicker Question #7

Diffusion requires energy.

a. True b. False

Clicker Question #8

Means that some substances can pass across easily and others

cannot.

a. Diffusion b. Homeostasis c. Selectively permeable d. Active transport

What is osmosis?Osmosis is another type of movement across a

membrane.

Osmosis is the diffusion of water through a selectively permeable membrane.

Lets look at a sugar-water solution.

One side of the membrane has a concentrated sugar solution and on the other side is a dilute sugar solution.

What type of molecule is sugar?

What does “Macro” mean?

Can sugar easily move across the membrane? No

Macromolecule

Large

What is osmosis?Sugar cannot move freely across the

membrane because it is too big.

The water moves from where there is more water to the area where there is more sugar.

So—in this situation, the water moves from an area of Low concentration of Solute to an area of High concentration of Solute.

Water “Chases” the sugar!

What are the 3 types of solutions?

There are 3 types of solutions.

1. Hypertonic2. Hypotonic3. Isotonic

Hypotonic Isotonic

Hypertonic

IsotonicAs you know a cell tries to reach equilibrium. This equal state is also known as an Isotonic solution.

Water is still moving in & out equally!

HypotonicExample of a Hypotonic solution: Freshwater (no solute)

The cell will have more salt in it and less outside of it.

In a Hypotonic solution, water rushes into the cell

causing the cell to expand and eventually burst.

Water “Chases” the solute into the cell

Low Concentration

HIGH Concentration

How to Remember!!!!

Hypo = EXPLODE

HypertonicExample of a Hypertonic solution: Saltwater

The cell will have less salt in it and MORE outside of it.

In a Hypertonic solution, water rushes out of the cell causing the cell to shrivel and shrink.

Water “Chases” the solute out of the cell

How to Remember!!!!

Hyper = shrink

Cells in Solutions

15%

Salt.1%

15%

15%

15%Salt

.1%5%

5%Salt

5%

5%

Hypo = Below

Hypo = Explode Hyper = ShrinkHyper = Above

Iso = Same

Clicker Question #9

Is the diffusion of water through a selectively permeable membrane.

a. Diffusion b. Osmosis c. Selectively permeable d. Homeostasis

Clicker Question #10

What does water “chase”?

a. Sugar or Salt b. Water c. Oxygen d. All of the above


Which of the following is an example of a hypotonic solution?

a. Sugar water b. Salt water c. Both (a) & (b) d. Fresh water


What type of solution is this cell in?

a. Hypertonic solution b. Hypotonic solution c. Isotonic solution d. None of above

.5%Salt

5%Salt

Clicker Question #13What type of solution are these cells

in?

a. Hypertonic solution b. Hypotonic solution c. Isotonic solution d. None of above

.5%Salt

What is facilitated diffusion?

Facilitated Diffusion is a process in which the cell membrane uses the protein channels to allow/help bigger molecules such as ions, sugars, and salts to cross in either direction.

This is still diffusion! No energy is used to move these molecules. The protein channels just “help” the molecules across.

Cell Membrane

Protein Channel

Solute

Video1. The membrane encloses the cell & keeps it _______ inside.

2. Molecules are always on the ______.

3. Molecules move _____ a concentration gradient.

4. Is energy added during passive transport?

5. When the solution is low, the cell will ________.

Video

Video Questions1. The membrane encloses the cell & keeps it _______ inside.

2. Molecules are always on the ______.

3. Molecules move ________ a concentration gradient.

4. Is energy added during passive transport?

5. When the solution is low, the cell will ____________________.

Answers

stable

move

down

NO

Swell & may burst

Active TransportNEEDS ENERGY!

From Low

To High

What type of cellular movement requires energy?

Sometimes, molecules move against the concentration gradient. This means that they are going from a lower area of solute to a higher area of solute. They are crazy!

For this, they need energy to move against the gradient/difference.

Example: Like walking up a hill.

You’ll need ENERGY!ATP = Energy

What type of cellular movement requires energy?

Active Transport uses the protein channels to move these molecules against the gradient with the input of energy.

This is the only movement that requires

energy!

This type of transport is often referred to as a pump.

Active transport…needs ENERGY!

Low concentration

of solute

HIGH concentration

of solute

1 2 3

12 3 4

5

Video1. Moving against the gradient requires _______.

2. Some materials move into & out of cells against their concentration gradient. It is called ________.

3. Active transport is sometimes called a ______.

4. Some large molecules must be absorbed into cells by a process called _________.

5. Think of exo- for ______.

Video…a little long….will not see all of it

Video Questions

1. Moving against the gradient requires _______.

2. Some materials move into & out of cells against their concentration gradient. It is called ___________.

3. Active transport is sometimes called a ______.

4. Some large molecules must be absorbed into cells by a process called ____________.

5. Think of exo- for ______.

Answers

Energy

Active Transport

Pump

Endocytosis

Exit

What are 2 types of Active Transport?

There are 2 types of Active Transport

1. Endocytosis is the process of taking material into the cell by means of in-foldings, or pockets, of the cell membrane.

This pocket, breaks loose from the cell membrane and forms a type of vacuole within the cytoplasm.

Large molecules, like food and other cells can be taken up by endocytosis.

Endocytosis

2. Phagocytosis is the process of large particles being taken into the cell by means of extensions of cytoplasm that go out and engulf the large particles.

This is a leukocyte (white blood cell) in your blood that is shooting out extensions to get the large particles that you see.

2 Types of Active Transport

2. Exocytosis is the cell’s ability to remove large amounts of materials out of the cell.

During exocytosis, the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell.

Clicker Question #14Process in which the cell membrane uses the

protein channels to allow/help bigger molecules such as sugars & salts to cross in either direction:

a. Osmosis b. Hypertonic solution c. Facilitated diffusion d. Equilibrium

?

Clicker Question #15Molecules move against the

concentration gradient. This means:

a. that it does not require energy b. that Solutes are equal on both

sides c. moving from a higher area of

solute to a lower area of solute d. moving from a lower area of

solute to a higher area of solute

Clicker Question #16Active Transport uses the ____ to move

molecules against the gradient with the input of energy.

a. Protein channels b. Lipid chains c. Nucleic acid double helix d. Carbohydrate channels

Clicker Question #17The process of taking material into the cell by means of in-foldings, or pockets, of the

cell membrane.

a. Osmosis b. Passive transport c. Exocytosis d. Endocytosis

The End

1. C 11. D2. D 12. B 3. B 13. A4. A 14. C5. B 15. D6. A 16. A7. B 17. D8. C9. B10.A

Clicker Question Answers

Documents

Unit 3 Movement Through The cell. Plasma Membrane/Cell Membrane Why is the cell membrane important? Selectively Permeable : A membrane that allows some