Cell Membrane

Integral Membrane Proteins Properties and Functions

Proteins embedded in the lipid bilayer.

Interact with hydrophobic layer.

Transport, Signalling, Enzymatic activity, Receptors.

Peripheral Membrane Proteins Properties and Functions

Proteins associated with membrane surface.

Regulatory, Structural, Cytoskeleton, (some) Enzymes, Signal Transduction

Sodium-Potassium Pump Function and Properties

Transmembrane Protein using ATP for Active Transport to maintain RMP.

Leak Channels

Channels allowing passive ion movement across membranes.

More Potassium leak channels than Sodium.

Integral Membrane Protein Types

Glycoproteins, Receptor proteins, Transport proteins, Junction proteins, Enzymes.

Glycoproteins

Proteins with carbohydrate groups for cell signalling and communication.

Receptor Proteins

Proteins that initiate cellular responses to signals through presence of a certain chemical.

Transport Proteins

Allow passage of hydrophilic substances (e.g. ions) across the membrane at appropriate times.

Junction Proteins

Connect cells to each other and allow them to communicate.

Enzymes

Biological catalysts, can line up together to create quick chemical reactions.

Ion Channels

Transmembrane proteins facilitating ion flow based on concentration gradients.

Hydrophobic substances repel charged particles, so ions need ion channels in order to pass through the Phospholipid Bilayer.

Ion Channel Types

Voltage-gated, Ligand-gated, Mechanically-gated, Phosphorylation-gated.

Voltage-Gated Channels

Channels that open in response to membrane voltage changes, and close with 'ball-and-chain'.

Ligand-Gated Channels

Channels that open in response to a chemical acting as a neurotransmitter.

Mechanically-Gated Channels

Channels that open in response to sensory stimulus, e.g. touch, pressure, vibrations.

Phosphorylation-Gated Channels

Channels that open as a result of chemical modification.