Hmm… If a cell needs glucose for energy, what does the glucose (needed for energy)

have to pass in order to get into the cell and to the mitochondria?

__________________________ also known as the: ______________________________

Cell Membrane: Function & Purpose

Functions:

Regulates ________________________________________________________________________

Also allows cell communication, identification and allows the ingestion and excretion of certain materials.

Life functions = ___________________________________________________________________

Helps the cell maintain _____________________________ by regulating what enters and leaves the cell.

Cell membrane only lets certain things in and out!

The cell membrane is ______________________________________ because it only lets certain

substances in and out.

Cell Membrane: Structure

What are the parts that make up the Cell Membrane?

Cell or Plasma Membrane is sometimes referred to as a _____________________________________

Made of ________________________ of Phospholipids

Phospholipid:

Polar head containing the element phosphorous

_______________________________________(Hydrophyllic)

Non-polar fatty acid tail

_________________________________ (hydrophobic)

Phospholipid Bilayer

Why is the membrane a bilayer?

Cell Membrane has more than just phospholipids…

Cell Membrane

How are things moved within a cell?

How does a cell get rid of waste and take in nutrients?

The cell membrane also ___________________________ inside it!

Help in cell ______________________________ and ____________________________ across the

membrane

Types of Membrane Proteins

1. Channel Proteins

2. Receptors

3. Glycoproteins

Membrane Proteins

1. _____________________________ (Transport Proteins): Molecules that are a little too large to pass into or

out of the cell use channel proteins to enter or leave.

2. __________________________________: Transmit information into the cell by reacting with certain

molecules. The part that sticks out has a specific shape and only molecules with the matching shape can bind

to it.

This is how some pathogens (such as viruses) attach to and enter cells!

3. _______________________________ (Glycoproteins): The name tags of the cell. Gives each cell its own

identity.

Label your Diagram!

Cell Membrane: Fluid Mosaic Model

Channel Protein Receptor Protein Fatty Acid Tail

Watery Cytoplasm Phospholipid Marker Protein

Phosphate Head

The cell membrane is a ______________________________________________ between the cell’s internal

environment and the outside environment

Fluid – Phospholipids and associated proteins move around like water in the ocean. The membrane is flexible.

Mosaic – So many different pieces make the membrane look like a mosaic or quilt.

Cell Membrane: Transport & Movement

What is transport?

The ____________________________ of material from one place to another.

There are 2 ways that material moves into and out of a cell

1. Transport that requires energy (ATP) is known as: ________________________

2. Transport that does not require energy is known as: ________________________________ or

____________________

Selectively Permeability of the Cell Membrane

Cell membrane DOES NOT let everything in and out of the cell!

Some materials cross membranes easily:

1. _________________________________________: water, oxygen, CO2, amino acids, glucose

Some materials do NOT cross membranes easily:

1. _________________________________________: Starches, proteins and other macromolecules

Hmmm….

Generally, what tells if a molecule will easily pass through a membrane?

WHY do molecules move?

1. The cell wants to maintain _________________________________

o Certain compounds enter the cell in order to maintain a stable internal environment. For example: if a

cell is low on oxygen, oxygen will move into the cell.

2. Concentration Gradient

o Difference in concentration where molecules move from areas of ________________________

_______________________________________________________________________________ to

maintain a dynamic equilibrium (homeostasis).

Dynamic Equilibrium = Homeostasis

______________________________________________________________________ back and forth across the

membrane but at an equal rate.

Small molecules pass through the cell membrane directly by squeezing through the phospholipids in the

membrane

Slightly ______________________________ cannot do this so they must use _________________

___________________

Two Types of Transport

1. Passive Transport: ____________________ required

1. Diffusion

2. Facilitated Diffusion

3. Osmosis

2. Active Transport: ___________________________

(ATP) for transport.

1. Active Transport

2. Endocytosis

3. Exocytosis

3 Types of Passive Transport

1. Diffusion

Diffusion - Movement of materials from an area of _________ concentration (more molecules in one

area) to an area of _____________ concentration (fewer molecules in an area).

Diffusion is ________________________________________________________________________ to

easily diffuse across the membrane.

2. Facilitated Diffusion

Facilitated diffusion – molecules move from areas of high to low

concentration _________________________________________

_____________________________________________________

Some molecules, such as __________________, are a little too

_____________ to pass through the membrane by simple diffusion.

These molecules need help and use __________________ _________________ to pass through the

membrane

3. Osmosis

Osmosis – Diffusion of ____________________. Water will move from areas of high to low

concentration.

Water will always move to where there is more

_____________________________________

(solute) in water.

Or, water will move from where it is more

concentrated to where it is less concentrated.

Osmosis Questions

1. Cell contains 10% salt and outside the cell contains 20% salt. Where will

water come from and go to? How much % water is in and out of the cell?

2. Cell contains 10% salt and the cell is put in distilled water. Where will

water come from and go to? How much% water is in and out of the cell?

3. Kenny was on a boat and forgot to pack water. He made a bad move and

drank salt water from the ocean. What will happen to the cells in his body?

4. Why do restaurants soak their lettuce and vegetables in water before they serve them?

To ______________________________

Which cells are at equilibrium, in salt water and in

distilled water?

A.___________________________

B.___________________________

C.___________________________

2 Types of Active Transport

Active Transport

What is used in active transport that is not used in passive transport (diffusion)?

Why would you need to use energy to transport molecules across a membrane?

1. Active Transport

Movement of a substance across a membrane _______________________________

This occurs when molecules are moving from areas of _______________________

___________________________________________________________________

Active transport occurs through special ______________________________ that

push / pull molecules into or out of the cell using energy.

Where is the concentration the highest?

How would blue diamond get into the cell?

Exocytosis

Exocytosis – type of active transport when ______________________________________________

______________________________________________________________________. Uses ATP

o Example – insulin leaves pancreatic cells by exocytosis

Vacuoles inside cell fuse / connect with the cell membrane and empty contents outside the cell

Endocytosis

Endocytosis – type of active transport where ________________ molecules, such as _______________, or large

amounts of material enter the cell. Uses ATP.

o Phagocytosis – membrane _______________________ and surrounds big molecule creating a

____________________.

Practice Problems

What happened to these plant cells?

Do Now’s & Workspace

Do Now 1

1. How is a plant cell different from an animal cell?

2. What life functions do the following cell organelles carry out?

a. Mitochondria

b. Cell membrane

c. Endoplasmic Reticulum

d. Ribosomes

3. Where are enzymes synthesized?

4. What makes one protein different from another?

DO NOW 2

Do Now 3

Name the molecule or structure: 1. Communicates messages to a cell. Found in the cell membrane.

2. Only 3 atoms big and is able to pass through a semipermeable membrane.

Compound Lipid Monosaccharide

Starch Enzyme Amino Acid

Big Molecule Small Molecule

Polysaccharide

Amino Acid

Glucose

Protein

Fatty Acid

Iodine Atom

3. Breaks down and synthesizes molecules needed by a cell.

4. Regulates the movement of molecules in and out of a cell

5. This structure allows slightly larger molecules to pass through the cell membrane.

Do Now 4

Draw arrows and show the movement of molecules.

Will the molecules even pass the semipermeable membrane? Why?

Do Now 5

Label the cell wall and cell membrane on the plant cell at equilibrium. Second, draw the plant cell when it is

placed in a salt water solution.

Do Now 6

Predict what will happen in this picture after diffusion occurs. Focus on the amount of molecules inside and outside the membrane.

I – Iodine G – Glucose

S – Starch