How does being a scaffold for biochemical activities apply to membranes?

All membrane lipids are amphipathic.

What does this mean?

A glycerol backbone esterbonded to two fatty acid chains and a hydrophilic head group.

Are amphipathic in character

Sphingosine linked to a fatty acid chain by it amino group. can have different molecules linked to the terminal alchohol to give different functions

Integral Proteins

Peripheral Proteins

Lipid-anchored Proteins

Proteins embedded in the plasma membrane with a cytolic domain, a transmembrane domain and an extracellular domain and are amphipathic.

Act as receptor that bind certain specific substances at the membrane surface, As transporters involved in the movement of ions and solutes across the membrane, or as agents that transfer electrons during the processes of photosythesis and cellular respiration.

Proteins linked to the plasma membrane by weak electrostatic bonds.

On the outside provide mechanical support for the membrane and function as an anchor for integral membrane proteins.

On the inside they function as enzymes, specialized coats, or factors that transmit transmembrane signals.

Som move randomly throughout the plasma membrane.

Some are immobilized.

Some move in a particular path.

Protein composition and mobility

The solute can pass through the lipid bilayer

 The solute can traverse an aqueous pore that spans the membrane.

The cell fills with water.

Because the interior of the cell has a higher concentration of solute than the outside water will rush in to try and dilute the solute inside the cell to the same as the outside.

The cell loses water.

Because the outside concentration is lower than that of the cell so the water will rush out of the cell to try and equalize the concentrations.

The cell neither gains nor loses water.

Because solute concentration are the same so water does not need to move in or out of the cell to equalize the concentrations.

When a plant cell is placed inside a Hypertonic medium, its volume shrinks as the plasma membrane pulls away from the surronding cell wall.

This is responsible for the wilting of plants and flowers

from a state of higher energy to one of lower energy

a membrane spaning protein that selectively binds to a substance to be brought into the cell.

Part of facilitated diffusion.

A concentration grandient.

An electrical gradient.

in the case of H a pH gradient.

sythesis in the ER

Processing in the Golgi

And materials shipped to the plasma membrane and released

Synthesis of Phospholipids

synthesis of steroids and hormones

glucose homeostasis(human specific)

store calcium

protein synthesis

Synthesis and attachment of carbohydrates

Some phospholipid synthesis

Messenger RNA

Transfer RNA w/ amino acids

Ribosomes

Floating or free in the cytosol

Or bound to the rough ER

All the proteins that function in the endomembrane system (in the lumen).

Make the integral proteins of the endomembrane system

All proteins that are to be released to function outside the cell.

Protein made in the ER

modified in the golgi

Sorted and packaged in the golgi

Shipped to endomembrane organelles

The SRP will bind to the Signal sequence, this puts it in a confirmation to bind to the ribosome that stops the synthesis of proteins.

This tells the ribosome it needs to be on the ER

When a vesicle leaves the ER the bilayer is already similar to the plasma membrane.

Enzymes in the cytosol switch head groups.

proteins shuttle head groups

The Golgi

because everything that comes out of the ER needs to be modified and polished in order to do work,

The molecules made in the ER are not functional yet,

They become functional after modifications by the golgi

Glycose amino Glycans

Complex polysaccharides that are deposited outside the plasma membrane

Physicall seperated compartments called Stacks.

The cis golgi

Back to the ER containing proteins that function in the ER

To the plasma membrane containing proteins that function that will function as part of the plasma membrane or proteins to be secrete

to The lysosomes containg proteins to function in the lysosome

Where does all protein sythesis begin?

Damged organelles need to be recycled(autophagy)

to breakdown food brought in and

to defend against foreign cells by eating the cell(phagocytosis)

For food

What are housekeeping receptors?

Are they digested by the lysosome?

structure and support of the cell

intercellular transport

movement of the cell

spacial organization

What are microtubles?

Protein of the cytoskeleton

composed of alpha and beta tubulin

cytoskeletal protein found in few organisms

built from different proteins in different cells

provide the path for the movement of vesicles

structure and organization of organelles

intracellular transport

component of mitotic spindle

component of cillia and flagella

the fattests of the components of the cytoskeletal

look like tubes or pipes

walls assembled alpha(-) beta(+) alpha beta etc.

one row is a protofilament

13 protofilaments make 1 microtuble

have dynamic stability

has polarity alpha end is negatibe

beta is positive

What are the two molecular motors for microtubles?

 What direction do they move?

they have the ability to hydrolize ATP

Cell migration

muscle contraction

cytokinesis

cytoplasmic streaming

cell walls made of peptidoglycan

and a capsule

the structure between the animal cell and the outside world

involved in cell to cell interaction

involved in cells receiving information

it is the gateway for the cell and all its interactions