18 Questions
What is the term for the movement of molecules across a membrane against their concentration or charge gradient?
Going against its gradient
Which type of molecule can move through a membrane without any assistance?
Nonpolar molecules
What is the process by which charged solutes move through a protein channel without requiring energy from ATP?
Secondary active transport
Which type of molecule is unable to move through a membrane?
Charged molecules
What is the term for the movement of molecules through a protein channel down their electrochemical gradient?
Facilitated diffusion
What is the result of primary active transport across a membrane?
The concentration gradient across the membrane increases
What is the term for the state of the bilayer where the interior is more fluid than solid and the acyl chains undergo much thermal motion?
Liquid-disordered state
What is the function of sterols in membrane biology?
To maintain the structure of the lipid bilayer
What is the main difference between the liquid-ordered state and the liquid-disordered state?
The organization of the acyl chains
What is the purpose of liposomes in biological systems?
To facilitate the transport of aqueous substances
What is the characteristic of the lipid bilayer in the gel phase?
The acyl chains are highly organized and have little thermal motion
What is the structure of a liposome?
A spherical sac with a bilayer of phospholipids
What is the main reason why uncatalyzed transbilayer movement of lipids is very slow?
The polar head group has to move away from a polar environment and through a hydrophobic bilayer.
What is the function of flippases in lipid movement?
To facilitate transbilayer movement of lipids.
What is the main component of the extracellular matrix (ECM) that provides structural support to surrounding cells?
Protein and sugar chains
What is the term for the movement of lipids from one side of the membrane to the other?
Transbilayer movement
What is the function of the cell membrane in relation to the intracellular matrix (ICM) and the extracellular matrix (ECM)?
To separate the ICM and ECM
What is the origin of the molecules that provide structural and biochemical support to the surrounding cells in the ECM?
Different cells that made and secreted these molecules
Learn about the two ways lipids in a membrane can move: lateral diffusion and transverse diffusion. Discover how enzymes called flippases can facilitate transbilayer movement. Understand the challenges of uncatalyzed transbilayer movement due to energy requirements.
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