Membrane Proteins (a) Movement of Molecules Across Membranes Flashcards
Regions of hydrophobic R groups allow…
Strong hydrophobic interactions that hold integral proteins within the phospholipid bilayer.
Some integral proteins are…
transmembrane
Integral membrane proteins interact extensively with the…
Hydrophobic region of membrane phospholipids
Periphiral membrane proteins have…
Hydrophilic R group on thier surface and are bound to the surface of membranes, mainly by ionic and hydrogen bond interactions
Many periphiral membrane proteins interact with…
The surface of integral membrane proteins
The phospholipid bilayer is a barrier to…
Ions and most uncharged polar molecules
Facilitated diffusion is the…
Passive transport of substances across the membrane through specific transmembrane proteins.
Different cell types have different channel and transporter proteins to…
Perform specialised functions
Most channel proteins in animal and plant cells are…
Highly selective
Some channel proteins are…
Gated and change conformation to allow or prevent diffusion
Ligand-gated channels are controlled by the…
binding of signal molecules
Voltage-gated channels are controlled by…
Changes in ion concentration
Channels are…
Multi-subunit proteins with the subunit arranged to form water-filled pores that extend across the membrane.
Steps of Transporter proteins
- Transporter proteins bind to specific substances to be transported
- The protein undergoes confornamtional changes
- Active transport uses pump proteins that transfer the solute across the membrane against the concentration gradient
- A source of metabolic energy is required for active transport
Some active transport proteins hydrolyse ATP directly to…
Provide the energy for the conformational change required to move the substance across the membrane.
