Membrane proteins Flashcards
What is a fluid mosaic model?
A model that describes the structure of the cell membrane.
What holds integral membrane proteins with the phospholipid bilayer?
Regions of hydrophobic R groups allow strong hydrophobic interactions that hold integral membrane proteins in the phospholipid bilayer.
What are transmembrane proteins?
The protein spans the entirety of the cell membrane.
What do peripheral membrane proteins have?
Peripheral membrane proteins have hydrophilic R groups on their surface and are bound to the surface of membranes, mainly ionic and hydrogen bonding interactions.
Do peripheral membrane proteins interact with integral membrane proteins?
Many peripheral proteins interact with the layers of the surfaces of integral membrane proteins.
What is the phospholipid bilayer?
The phospholipid bilayer is a barrier to ions and most uncharged polar molecules.
What can go through the phospholipid bilayer?
Some small molecules such as water and oxygen and carbon dioxide can pass through the bilayer by simple diffusion.
What is facilitated diffusion?
The passive transport of substances across the membrane through specific transmembrane proteins.
Why do different cell types have different channel and transporter proteins?
To perform specialised functions, different cell types have different channel and transporter proteins.
Are channel proteins highly selective?
Channel proteins in animal and plant cells are highly selective. This means they let very few types of molecules pass through.
How do channel proteins affect diffusion?
Some channel proteins are gated and change conformation to allow or prevent diffusion.
How are ligand-gated channels controlled?
Ligand channels are controlled by the binding of signal molecules.
How are voltage-gated channels controlled?
Voltage-gated channels are controlled by changes in ion concentration.
How do transporter proteins transfer solute across membranes?
Transporter proteins bind to the specific substance to be transported and undergo a conformational change to transfer the solute across the membrane.
What does active transport use to transfer substances across the membrane?
Active transport uses pump proteins that transfer substances across the membrane against their concentration gradient.