Unit #1: Wellness And HomeostasisCellular Biology and Homeostasis (2)

“The Cell Membrane”

Cell Membrane • Also called the Plasma

Membrane

• This organelle is responsible

for bringing essential materials

into the cell and moving

metabolic waste products out

of the cell

(A) Lipid Bilayer • The major feature of the cell

membrane

• Made of 2 layers of Phospholipid

Molecules

• The Phosphate “Head” is Hydrophilic

(water-soluble)

• The Carbohydrate “Tail” is

Hydrophobic (NOT water – soluble)

• The bilayer allows any water

soluble molecule small enough to fit

between the phospholipids to pass

into or out of the cell

(E) Cholesterol Molecule

• A type of Steroid Lipid

• These molecules are embedded

within the cell membrane

• Their function is to keep the

membrane “fluid” and

“flexible”

– create space between the

carbohydrate tails of the

phospholipids so that they do not

get “locked” in one position

(F) Integral Protein

(G) Peripheral Protein

• These are proteins embedded in

the cell membrane

• Their function is to provide

“channels” for bigger ions and

molecules to pass into the cell

• These are structural proteins that

sit on the inside of the cell

membrane and are connected to

the cytoskeleton filaments

(I) Alpha Helix Proteins

(J) Glycoprotein

• A coil like protein that extends

that extends through the

membrane

• Acts as a channel for nutrients

entering the cytoplasm

• The “ID Tag” of the cell

• These are proteins attached to

carbohydrates that stick out from

the outside of the cell

• Acts as receptors for hormones

and other cells in the body