Prepare for NEET Biology Cell: The Unit of Life with MCQs & PYQs on NEET.GUIDE. Enjoy free practice, previous year questions, and expert solutions to understand cell structure and function.
The presence of hopanoids in some prokaryotic plasma membranes primarily contributes to:
Protein synthesis
Nutrient transport
Membrane stability
Photosynthesis
Certain integral membrane proteins facilitate the passage of water across the cell membrane. These proteins are known as aquaporins and are crucial for maintaining cellular water balance. Which of the following is NOT a characteristic of aquaporin-mediated water transport?
Passive transport of water
Saturable transport kinetics
Driven by osmotic gradients
High selectivity for water
Lipid rafts are specialized microdomains within the cell membrane. Which of the following statements about their composition and function is INCORRECT?
They are enriched in cholesterol and sphingolipids.
They are involved in signal transduction and membrane trafficking.
They exhibit reduced fluidity compared to the surrounding membrane.
They are primarily composed of unsaturated phospholipids and peripheral membrane proteins.
The cell membrane maintains a distinct phospholipid composition between its inner and outer leaflets. Which of the following transport mechanisms is primarily responsible for establishing and maintaining this asymmetry?
Simple diffusion
Facilitated diffusion
Flippases
Ion channels
Which type of membrane protein is MOST likely to be involved in cell-cell recognition and adhesion?
Peripheral membrane proteins
Integral membrane proteins without glycosylation
Glycoproteins
Channel proteins
The fluidity of the cell membrane is influenced by several factors. Which of the following would DECREASE membrane fluidity?
Increased proportion of unsaturated fatty acids
Shorter fatty acid chain length
Increased cholesterol content at high temperatures
Decreased cholesterol content at low temperatures
A researcher is studying the transport of a novel molecule across a synthetic lipid bilayer. They observe that the molecule moves down its concentration gradient without the need for any membrane proteins or energy input. However, the rate of transport is significantly slower than predicted for simple diffusion. Which of the following BEST explains this observation?
The molecule is very large and its size restricts diffusion through the membrane.
The molecule is charged and is repelled by the hydrophobic core of the bilayer.
The molecule is polar and its passage is hindered by the hydrophobic core of the bilayer.
The molecule is binding to a specific receptor on the membrane surface, slowing its diffusion.
Which of the following is NOT a primary function of cell membrane proteins?
Transporting molecules across the membrane
Acting as receptors for signaling molecules
Synthesizing lipids
Providing structural support to the membrane
The fluidity of the cell membrane is primarily influenced by the:
Amount of cholesterol present
Saturation level of fatty acid tails in phospholipids
Concentration of peripheral proteins
Presence of glycoproteins
Which component of the cell membrane is primarily responsible for its selective permeability?
Glycoproteins
Peripheral proteins
Phospholipid bilayer
Cholesterol
