Question

Question 24 Which of the following categories of membrane proteins is most likely to have restricted lateral mobility in a membrane? enzyme transporter O anchor O receptor all are restricted Question 5 New membrane synthesis occurs by spontaneous aggregation of free phospholipids into a new bilayer incorporation of phospholipids into one face of a preexisting membrane and their specific redistribution by enzymes like flippases incorporation of phospholipids into both faces of a preexisting membrane at the same time formation of chains of liposomes none of these "Upon new membrane synthesis, which of the following can be used to transport the new membrane to its final destination in the cell?" O vacuoles O liposomes O nuclear pores O vesicles O none of these Question 8 The types of passive transport include: O ATP-driven O Light-driven O Coupled transport ATP-driven and light-driven O none of these Question 18 Which of the following is a type of peripheral membrane protein based on its chemistry? transmembrane protein-attached lipid-linked monolayer-associated none of these

Answer 1

1. As the name suggests, anchor proteins are membrane proteins that are anchored at a specific position in the membrane due to covalent interactions with the lipids in the membrane and have restricted lateral movement. Transport proteins, enzymes and receptors constantly move laterally in the membrane as their functions require movement to bind to specific ligands or targets.

2. New memberane components are synthesised inhe cytoplasmic side of the cell and are incorporated into one side of the membrane followed by which these components are redistributed to the other side of the membrane by enzymes such as flippases and floppases.

3. Phospholipids and membrane proteins are mostly synthesised in the ER and Golgi bodies and are packed in vescicles that bud off from these organelles and transported to their final destinations.

4. Passive transport is the movement of molecules across mthe membrane without the requirent of energy. It occurs due to adifference in concentration of the solute across the membrane. On the other hand ,in active transport the movement is against the concentration gradient and thus it requires energy, which is derived from ATP, light etc. Coupled transport is known as secondary active transport,where a molecules use the concentration gradient created by the active transport of another molecule , for their own transportation. So the correct answer is ,none of these.(last option).

5. Transmembrane proteins traverse across the membrane throughout it's hydrophobic regions, lipid linked proteins are also attached covalently to the hydrophobic regions and monolayer associated are located on the cytoplasmic side of the cell.Peripheral proteins are generally attached to the integral proteins hence protein attached membrane proteins are generally peripheral proteins .