CSIR NET PYQ PRACTICE

Apna result mention kro

The cell membrane can maintain different protein compositions in its domains because: A) All membrane proteins freely cross every cellular compartment B) Diffusion barriers and selective trafficking restrict movement C) Membrane proteins are synthesized inside the lipid bilayer D) Proteins cannot interact with lipids

A membrane protein that transports ions down their electrochemical gradient without ATP is most likely: A) A primary ATPase B) A DNA helicase C) An ion channel or facilitated transporter D) A ribosomal protein

Ion channels differ from carrier proteins because ion channels generally: A) Bind and chemically modify every transported ion B) Transport molecules only against their gradients C) Require covalent attachment of ATP to each ion D) Provide an aqueous pathway through the membrane

Which statement best distinguishes channels from carriers? A) Channels usually transport solutes through a continuous aqueous pore, whereas carriers undergo conformational cycles B) Carriers never show substrate specificity C) Channels always require ATP hydrolysis D) Carriers transport only lipids and never ions

A membrane protein contains a positively charged residue within its transmembrane region. Its presence may be explained by: A) Complete absence of functional importance B) Interaction with another charged residue or involvement in ion transport C) Requirement for cellulose synthesis D) Permanent exposure to bulk water

The carbohydrate portions of glycoproteins and glycolipids are generally found: A) Only on the cytosolic surface B) In the hydrophobic membrane core C) Between fatty-acid tails D) On the non-cytosolic surface of the membrane

Which membrane component is most directly responsible for cell–cell recognition? A) Fatty-acid tails B) Cholesterol rings C) Membrane-associated carbohydrates D) Phospholipid phosphate groups only