Prepare for NEET with Botany-specific practice questions. Covering all major Botany chapters, this is perfect for your NEET Biology needs.
The presence of hopanoids in some prokaryotic plasma membranes primarily contributes to:
Protein synthesis
Nutrient transport
Membrane stability
Photosynthesis
In a recalcitrant seed, which physiological factor is PRIMARILY responsible for its inability to withstand desiccation?
Presence of germination inhibitors that prevent metabolic slowdown
Lack of protective proteins that stabilize cellular components during drying
High sensitivity of cellular membranes to dehydration damage
Rapid depletion of stored reserves during the early stages of desiccation
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.
During plasmolysis, the cell membrane separates from the cell wall. This separation is primarily due to:
The expansion of the cell wall due to increased turgor pressure.
The shrinking of the protoplast due to water loss.
The breakdown of the cell wall by hydrolytic enzymes.
The active transport of water out of the cell.
A plant with a mutation that disables aquaporins in its root cells would likely exhibit:
Complete cessation of water uptake.
Enhanced water uptake due to increased reliance on the apoplast pathway.
Reduced rate of water uptake but not complete cessation.
No change in water uptake as aquaporins are primarily involved in transpiration.
