Date: November 18, 2015Aim #27: How does the structure of the cell membrane contribute to its function?

HW:1) Quiz next Tuesday 11/24 and Wednesday 11/252) “Song of the Cell” due Friday3) Cell Organelle Worksheet

Do Now: Warm-Up NotebookDate Title of Activity Page #11/19 Ribosomes and ER 48

Aim #27: How does the structure of the cell membrane

contribute to its function?

1) What is the function of the structure below?

CELL MEMBRANE

Its function is to CONTROL what enters and exits the cell. It also provides protection and support.

2) What is the cell membrane made up of?

•Phospholipids• Proteins

3) What is a phospholipid?• The cell membrane is composed of a special type of

lipid (fat) called a phospholipid.

This part of the phospholipid is afraid of water and tries to avoid it.

PHOSPHOLIPID BI-LAYER

phospholipids

4) What are types of proteins in the cell membrane?

STRUCTURAL PROTEIN

CHANNEL

Membrane Proteins:

1. Structural Proteins:

2. Transport Proteins: (Channels)

3. Receptor Proteins

4. Enzymes

5) What are receptors?

RECEPTORS

Receptors found on the cell surface aid in cell to cell communication. Messengers (hormones) from other cells bind to these receptors (based on shape) and transfer information. Carbohydrate chains attached to the surface are important for cell-to-cell recognition.

Receptors on cell membrane are involved in cell communication

Signal 1 is released from cell B and sent to cell A

Signal 2 is released by cell A and sent to cell B

Cell receptor

(receptor molecule)

6) Why is this model called the fluid mosaic model?

http://home.earthlink.net/~shalpine/anim/Life/memb.htm

Fluid because the molecules are always changing position with each other and mosaic because it is made of different kinds of molecules.

+ =

Fluid Mosaic Model…

How is the cell membrane different from an umbrella?

An umbrella is impermeable

It does not allow materials through

7) How is an umbrella different from a window

screen?

The window screen is permeable

It allows materials through

How is a window screen similar to the cell

membrane?The cell

membrane is permeable-it

allows materials through

8) Do all things get through the cell membrane?

The cell membrane is SELECTIVELY PERMEABLE because it allows certain substances through and prevents other substances from passing.

NO!

What is the difference between these molecules?

Can the elephant get into the house?

Why do some things get through the cell membrane?Small molecules are more likely to get through the

cell membrane compared to big molecules

10) What will get through thecell membrane?

• Water• Glucose• CO2

• O2

• And other small molecules

Lipid: hydrophilic head

lipid

Lipid: hydrophobic tail

Protein

Big Cell Membrane Foldable Activity

1. Phospholipid

• Main component of cell membranes• Each phospholipid contains a polar

head that is made up of phosphate and choline and it contains two nonpolar fatty acid tails.

• All the non-polar tails turn towards one another in an attempt to exclude as much water (which is a polar molecule) as possible.

2) Phospholipid bilayer

• Two layers of phospholipids that are arranged so that each layer has its hydrophobic fatty acid tails facing each other to create a hydrophobic core.

• Selectively permeable

3) Integral Protein

• Have at least one region embedded within the hydrophobic core of the bilayer.

• Transmembrane proteins are the most typical type of integral proteins. They span the entire bilayer.

4) Peripheral Protein

• Proteins that lie on and are secured to the inner or outer surface of the cell membrane.

• Do not interact with the hydrophobic core of the bilayer.

5) Cholesterol

• Provide the membrane with the proper amount of fluidity and stability.

• Plant and bacterial cells do not contain cholesterol in their cell membranes.

6) Glycolipid

• Phospholipid contains a sugar chain on its surface.

• Function as markers for cell recognition.

7) Oligosaccharide (Sugar Chain)

• Short chain or branched chain of sugars that are attached to certain proteins and phospholipids on the membrane. This modification of the membrane only exists on the outside surface.

8) Glycoprotein

• Protein that contains a sugar chain on its surface.

• Serve many different functions from structural components to receptors to enzymes.

9) Transport

• Transport proteins are used to help substances that cannot cross the lipid bilayer move across the membrane. These substances cannot cross because they are charged (ions) or too large (glucose) or both (amino acids). Transport proteins are used for facilitated transport and active transport.

10) Attachment and Recognition

• Proteins that are exposed on the intracellular and extracellular side of the membrane can have attachment sites for different elements on either side of the membrane.

11) Receptor for signaling

• These proteins are receptors that can bind to hormones. When bound they can trigger a signal that begins a cascade of reactions within the cell.

12) Enzymatic Activities

• Involved in catalyzing biochemical reactions