plasma membrane

Phospholipid arrangement in the plasma membrane

A bilayer structure formed by molecules with hydrophilic heads facing outward toward water and two hydrophobic tails facing inward away from water.

Integral vs. peripheral membrane proteins

Integral proteins span the entire membrane (acting as receptors, channels, or enzymes), while peripheral proteins attach only to the inner or outer surfaces.

Role of membrane carbohydrates

Attached to proteins (glycoproteins) or lipids (glycolipids) to facilitate cell recognition and intercellular communication.

Role of cholesterol in the membrane

Interspersed within the bilayer to maintain membrane fluidity and stability during temperature variations.

Fluid Mosaic Model

A description of the plasma membrane as a flexible, dynamic structure where lipids and proteins move laterally.

Membrane cytoskeleton

An internal network of protein filaments that anchors membrane proteins and supports cell shape.

Intercellular connections in tissues

Junctions such as tight junctions or desmosomes that join cells together to maintain tissue structure and integrity.

Selective permeability of the bilayer

The property allowing small non-polar molecules (like $O_2$ and $CO_2$) to diffuse freely while restricting ions and large polar molecules.

Passive vs. active transport via membrane proteins

Passive transport uses channels or carriers to move substances down concentration gradients without energy, whereas active transport requires energy.

Signal reception in the plasma membrane

Process where membrane protein receptors bind extracellular signaling molecules like hormones to trigger internal cellular responses.

Phospholipid bilayer

The fundamental double-layer structure of the plasma membrane, composed of hydrophilic heads facing outward and hydrophobic tails facing inward.

Integral proteins

Proteins embedded within the plasma membrane that span the entire length of the phospholipid bilayer.

Peripheral proteins

Proteins attached to or associated with only the outer or inner surfaces of the plasma membrane.

Glycoproteins and glycolipids

Carbohydrate chains attached to membrane proteins or lipids that play a key role in cell recognition and intercellular communication.

Cholesterol (in plasma membrane)

Molecules interspersed within the phospholipid bilayer that help regulate membrane fluidity and stability during temperature changes.

Fluid Mosaic Model

A model describing the plasma membrane as a dynamic and flexible layer where phospholipids and proteins can move laterally.

Membrane cytoskeleton

An internal network of protein filaments that anchors membrane proteins and helps maintain cellular shape.

Intercellular connections in tissues

Junctions such as tight junctions or desmosomes that join cells together to maintain tissue structure and integrity.

Selective permeability

The property of the lipid bilayer allowing small non-polar molecules (like $O_2$ and $CO_2$) to diffuse freely while restricting ions and larger polar molecules.

Transport proteins

Integral membrane proteins forming channels or carriers to facilitate passive or active movement of substances across the membrane.

Signal reception

The mechanism by which membrane receptors bind

Phospholipid bilayer

The fundamental double-layer structure of the plasma membrane, composed of hydrophilic (water-attracting) heads facing the external and internal aqueous environments, and hydrophobic (water-repelling) tails facing inward toward each other.

Structure of a phospholipid

An amphipathic molecule consisting of a polar, hydrophilic head containing a phosphate group and glycerol, attached to two non-polar, hydrophobic hydrocarbon (fatty acid) tails.

Integral proteins

Proteins embedded within the plasma membrane that span the entire length of the phospholipid bilayer.

Peripheral proteins

Proteins attached to or associated with only the outer or inner surfaces of the plasma membrane.

Glycoproteins and glycolipids

Carbohydrate chains attached to membrane proteins or lipids that play a key role in cell recognition and intercellular communication.

Cholesterol (in plasma membrane)

Molecules interspersed within the phospholipid bilayer that help regulate membrane fluidity and stability during temperature changes.

Fluid Mosaic Model

A model describing the plasma membrane as a dynamic and flexible layer where phospholipids and proteins can move laterally.

Membrane cytoskeleton

An internal network of protein filaments that anchors membrane proteins and helps maintain cellular shape.

Intercellular connections in tissues

Junctions such as tight junctions or desmosomes that join cells together to maintain tissue structure and integrity.

Selective permeability

The property of the lipid bilayer allowing small non-polar molecules (like $O_2$ and $CO_2$) to diffuse freely while restricting ions and larger polar molecules.

Transport proteins

Integral membrane proteins forming channels or carriers to facilitate passive or active movement of substances across the membrane.

Signal reception

The mechanism by which membrane receptors bind to extracellular signaling molecules like hormones to induce cellular responses.