Cell Membrane Structure

What is the primary element of the cell membrane?

Phospholipid

What is the base of a phospholipid?

Glycerol

When dropped in water, what do phospholipids do?

Float with their tails in the air.

What happens when you agitate water with phospholipids on the surface?

They form micelles

Phospolipids are _____

Amphipathic

In a phospholipid bilayer, what parts touch?

The tails

What is an integral protein?

Proteins that go all the way through the cell membrane

Where are perhipheral proteins?

Usually on top of or hang off of integral proteins, or are partially embedded in the cell membrane.

What is cholesterol’s role in the cell membrane?

Modulates fulidity

What kind of molecule is cholestrol?

Sterol

What are the 3 types of transport?

Simple Diffusion, Facilitated Diffusion, Active Transport

What is the simplest kind of transport?

Simple diffusion

What is simple diffusion?

The diffusion of molecules across the cell membrane without assistance

What is facilitated diffusion?

The diffusion of molecules across the cell membrane with assistance from channel or carrier proteins.

What kind of membrane proteins are transport proteins

Integral proteins

What kind of transport protein is facilitated diffusion?

Channel and Carrier

What kind of transport requires energy?

Active Transport

What is diffusion?

The net movement of particles from high to low concentration

Many of the proteins on the cell membrane are what kind of protein?

Enzymes

What is an example of a membrane bound enzyme?

ATP Synthase

What are Brush Border Immobilized Enzymes?

Found in the lumen of the S. Intestine, and grab nutrients and use enzymes to get glucose.

Glycoproteins in the cell membrane usually have what role?

Recognition Proteins

Are recognition proteins integral or peripheral?

Both

What is an example of recognition proteins?

Blood type

What are adhesion proteins?

Connect cells to the ECM

Adhesion fibers connect to what element of the cytoskeleton?

Actin

What is the order from inside to outside of how cell connect to the ECM?

Actin → Integrin → Fibronectrin → ECM

What kind of adhesion protein holds skin together?

Desmosomes

What is a receptor protein?

Receive messages of very specific chemical messenger

What are some examples of receptor proteins?

Beta-Adrenergic Receptor, Insulin Receptor

What does selective permeability mean?

Only some molecules will be allowed to pass through.

What kind of molecules are the least permeable?

Ions/Formally Charged molecules

What kind of molecules are the most permeable?

Small, nonpolar molecules

How much energy is requited for diffusion?

None, molecules will do this naturally

What is the concentration gradient?

The gradient from high concentration to low concentration of molecules; the direction that molecules want to move

What kind of gradient is the concentration gradient?

Electrochemical gradient

What is osmosis?

Movement of water through the cell membrane by diffusion

Osmosis is what kind of transport?

Passive transport/Simple diffusion

What is osmoregulation?

Cells controlling the amount of water inside them

Why does water move (osmosis)?

Because of the solutes in the water.

If solutes can cross the cell membrane through proteins or otherwise, will there be osmosis?

No

What is the solute concentration of hypertonic?

Higher concentration of solutes, lower concentration of water

What is the solute concentration of isotonic?

Equal concentrations of both sides of the membrane

What is the solute concentration of hypotonic?

Lower concentration of solutes, larger concentration of water

Water flows from what tonicity to what tonicity?

Water flows from hypotonic to hypertonic

What happens to animal cells in a hypotonic solution?

Lyse

What happens to animal cells in a hypertonic solution?

Crenate

What happens to a plant cell in a hypotonic solution?

They become turgid

What happens to a plant cell in an isotonic solution?

They become flacid

What happens to plant cells in a hypertonic solution?

They become plasmolyzed

What tonicity do animal cells like?

isotonic

What tonicity do plant cells like?

Hypotonic

When is water potential positive?

Never

What is the water potential of distilled water?

0 MPa

What units does water potential use?

(Mega)pascals

What two components make up water potential?

Solute potential and Pressure potential

When does pressure potential equal zero?

At 1 atm

Is the solute potential of a hypertonic solution higher or lower than a hypotonic solution?

Lower

Is the solute potential of a hypotonic solution higher or lower than a hypertonic solution?

Higher

Water flows from ____ water potential to ____ water potential

high → low