What is the cell membrane? AKA: Plasma membrane The boundary between the cell and the environment...

What is the cell membrane?AKA: Plasma membraneThe boundary between the cell and the

environmentDoes every cell have a cell membrane?

Yes!, Each and every cell has a cell membrane.

How do cell membranes help to maintain homeostasis?

The cell membrane allows nutrients to come into the cell

Glucose, amino acids, lipids

The cell membrane removes waste

Selective PermeabilityThe cell membrane lets some molecules in

and keeps others out

EX. A cell is low on glucose so the membrane lets in some glucose, but does not overfill the cell with the monomer.

Structure of the cell membraneWhat does the cell membrane look like up

close?

Lets look at one of these

structures up close

Structure of cell membranePhospholipids

Phosphate headGlycerol2 Fatty acid tails

Phospholipids1.) Phosphate Head

Polar Hydrophilic Make up the outer borders of the

membrane

2.) Fatty Acid Tails Nonpolar Hydrophobic Make up the inner part of the

membrane

Structure of cell membranePhospholipid bilayer

2 layers of phospholipids make up a cell membrane

Phospholipid BilayerRemember polar heads and nonpolar tails

The fluid Mosaic Model of the cell membraneLipid bilayer is not strong & firm

like a hard shell, but it is fluid like a soap bubble consistency

So, it is called the Fluid Mosaic Model (fluid like, with many proteins stuck in it)

The fluid Mosaic Model of the cell membrane

It is a flexible membrane, made fluid because of cholesterol molecules located in the phospholipid bilayer.

Proteins in the membrane move around.

Other components of the cell membraneCholesterol

Helps to stabilize the phospholipids and keep them from sticking together

Other components of the cell membraneCarbohydrates- linked to lipids or proteins

Recognition of Cells – “Name tag of cell”Ex. Is the cell a heart cell, liver cell, or brain cell?Ex. Glycolipids & Glycoproteins (marker protein)

Other components of the cell membrane

Proteins- make up 50 %- 70% of membraneRegulate which molecules enter

and which molecules leave a cell.Receive info & ID the cell

Types of proteins in the cell membraneCarrier Protein

Allow needed substances or waste materials to move through the cell membrane

Types of proteins in the cell membraneReceptor Protein

These have binding sites for molecules such as hormones or substrates to bind to that can cause a chemical rxn in the cell

Types of proteins in the cell membraneChannel or Pore protein

Hydrophilic channel – allows lipid insoluble substances to pass in and out of cell.

Types of proteins in the cell membraneGlycoproteins

Protein with what macromolecule attached to it? Carbohydrate

Functions for cell to cell recognition

Where are proteins located in the cell membrane?

Integral ProteinsProteins inside the cell membrane

Peripheral ProteinsProteins outside the cell membrane

Lets build a cell membrane togetherhttp://www.wisc-online.com/objects/

index_tj.asp?objid=AP1101 Cell membrane animation

Cell membranes help maintain homeostasis, what is that?

Cel

ls b

reat

hin...

Cel

ls g

ettin

g ...

Cel

ls m

aint

ain...

Cel

ls re

produc

...

25% 25%25%25%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

1. Cells breathing2. Cells getting blood

to them3. Cells maintaining

internal conditions4. Cells reproducing

Where would you expect to find water in this cell membrane?

Her

e H

ere

50%50%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

1. Here2. Here

When something is hydrophilic, it…

Has

a c

hemic

al...

Has

a c

hemic

al...

50%50%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

1. Has a chemical makeup that likes to be around water

2. Has a chemical makeup that does not like to be around water

This picture shows what type of protein?

Rec

epto

r Pro

te...

Chan

nel P

rote

i...

Gly

copro

tein

Car

rier P

rote

i...

25% 25%25%25%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

1. Receptor Protein2. Channel Protein3. Glycoprotein4. Carrier Protein

Identify the structure marked on the cell membrane:

Phosp

holipid

Chole

ster

ol

Rec

epto

r pro

te...

Chan

nel p

rote

i...

Gly

copro

tein

Car

rier p

rote

i...

Nucl

eic

acid

14% 14% 14% 14%14%14%14%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

1. Phospholipid2. Cholesterol3. Receptor protein4. Channel protein5. Glycoprotein6. Carrier protein7. Nucleic acid

Identify the structure marked on the cell membrane:

Phosp

holipid

Chole

ster

ol

Rec

epto

r pro

te...

Chan

nel p

rote

i...

Gly

copro

tein

Car

rier p

rote

i...

Nucl

eic

acid

14% 14% 14% 14%14%14%14%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

1. Phospholipid2. Cholesterol3. Receptor protein4. Channel protein5. Glycoprotein6. Carrier protein7. Nucleic acid

Identify the structure marked on the cell membrane:

Phosp

holipid

Chole

ster

ol

Rec

epto

r pro

te...

Chan

nel p

rote

i...

Gly

copro

tein

Car

rier p

rote

i...

Nucl

eic

acid

14% 14% 14% 14%14%14%14%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

1. Phospholipid2. Cholesterol3. Receptor protein4. Channel protein5. Glycoprotein6. Carrier protein7. Nucleic acid

Identify the structure marked on the cell membrane:

Per

ipher

al P

ro...

Inte

gral P

rote

...

50%50%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

1. Peripheral Protein2. Integral Protein