Biological Membranes

Flashcards covering key concepts related to biological membranes, their structure, functions, and transport mechanisms.

Biological membranes are composed of __, other lipids, proteins, and carbohydrates.

phospholipids

The __ model describes the structure of membranes as a mosaic of proteins floating in a fluid lipid bilayer.

fluid mosaic

Phospholipids spontaneously form a bilayer with on the outside and on the inside.

phosphate groups; fatty acids

Membrane fluidity is influenced by saturation and the presence of .

fatty acid; sterols

Transmembrane proteins __ the entire membrane, while integral proteins only partially penetrate the membrane.

cross

The movement of water by __ is influenced by tonicity and solute concentration.

osmosis

In __ transport, molecules move against their concentration gradient and require energy.

active

The __ pump actively transports Na+ out of and K+ into the cell.

Na+/K+

Endocytosis and exocytosis are forms of __ transport that involve vesicle formation to move substances in and out of the cell.

active

Facilitated diffusion requires __ but no energy input from the cell.

transport proteins

Channel proteins provide __ for ions and small molecules to pass through the membrane.

hydrophilic channels

The process of __ involves the uptake of large particles or cells by a cell.

phagocytosis

The __ gradient drives the passive movement of molecules across the lipid bilayer.

concentration

__ are proteins that assist in the transport of materials across the cell membrane without using energy.

Carrier proteins

Aquaporins are specialized proteins that facilitate the transport of __ in and out of the cell.

water

During exocytosis, materials are transported out of the cell by the fusion of vesicles with the __.

plasma membrane

The absence of LDL receptors in familial hypercholesterolemia leads to cholesterol accumulation in the __.

bloodstream