Cell Cell MembraneMembrane

FunctionFunction

1.1. Separates cytoplasm from external Separates cytoplasm from external environmentenvironment

2.2. Regulates what enters and leaves Regulates what enters and leaves cellcell

3.3. Cell identificationCell identification4.4. Cell-cell communicationCell-cell communication

Plasma membrane regulates Plasma membrane regulates movement of materials due to movement of materials due to its its chemical composition:chemical composition:

PhospholipidsPhospholipidsCholesterolCholesterol

ProteinsProteins

PhospholipidsPhospholipids Phospholipids BilayerPhospholipids Bilayer Phospholipids

have:1. Hydrophilic head

2.Nonpolar hydrophobic tail

Hydrophilic "heads" faces the watery environment inside and outside cell

Hydrophobic tail forced to face inward – away from water.

Cell Cell MembraneMembrane

FunctionFunction

1.1. Separates cytoplasm from external Separates cytoplasm from external environmentenvironment

2.2. Regulates what enters and leaves Regulates what enters and leaves cellcell

3.3. Cell identificationCell identification4.4. Cell-cell communicationCell-cell communication

Plasma membrane regulates Plasma membrane regulates movement of materials due to movement of materials due to its its chemical composition:chemical composition:

PhospholipidsPhospholipidsCholesterolCholesterol

ProteinsProteins

PhospholipidsPhospholipids Phospholipids BilayerPhospholipids Bilayer Phospholipids

have:1. Hydrophilic head

2.Nonpolar hydrophobic tail

Hydrophilic "heads" faces the watery environment inside and outside cell

Hydrophobic tail forced to face inward – away from water.

The phospholipids are not bound The phospholipids are not bound

together – gives the membrane a together – gives the membrane a fluid fluid

nature nature

CHOLESTEROLCHOLESTEROL Function:Function:1.1. Stabilizes membrane (structural Stabilizes membrane (structural

support)support)2.2. Cell communication (cell-cell and Cell communication (cell-cell and

cell-hormone)cell-hormone)

Some interesting factsSome interesting facts Most common molecule in Most common molecule in

membrane (>50%)membrane (>50%) Due small size and weight – only Due small size and weight – only

20% of membrane mass20% of membrane mass Is an amphipathic molecule Is an amphipathic molecule

Homework Homework – find out what this – find out what this meansmeans

ProteinsProteins Are embedded in membrane Are embedded in membrane Serve different functionsServe different functions

FunctionsFunctions 1. Channel Proteins - small openings for 1. Channel Proteins - small openings for

molecules to diffuse throughmolecules to diffuse through 2. Carrier Proteins- binding site on protein 2. Carrier Proteins- binding site on protein

"grabs” molecules, pulls them into cell"grabs” molecules, pulls them into cell 3. Receptor Proteins – act as triggers that 3. Receptor Proteins – act as triggers that

set off cell responses (such as release of set off cell responses (such as release of hormones or opening of channel proteins)hormones or opening of channel proteins)

4. Cell Recognition Proteins - ID tags, 4. Cell Recognition Proteins - ID tags, identify cell to immune systemidentify cell to immune system

5. Enzymatic Proteins - carry out 5. Enzymatic Proteins - carry out metabolic reactionsmetabolic reactions

LABEL YOUR DIAGRAM WITH THE FOLLOWING DETAILSLABEL YOUR DIAGRAM WITH THE FOLLOWING DETAILS

Task: Task: Due Wed. Feb 15.Due Wed. Feb 15.

Read pages 47 -49 in your textRead pages 47 -49 in your text Answer questions 1 – 5 in practice Answer questions 1 – 5 in practice

sectionsection Explain the structure and function of Explain the structure and function of

glycoproteins.glycoproteins. How are liposomes used in cancer How are liposomes used in cancer

treatment and gene therapy?treatment and gene therapy? What role might receptor proteins have What role might receptor proteins have

in medical disorders such as in medical disorders such as HypertensionHypertension? ?