Tag: plant physiology

Apoplast pathway consists of non-living parts of plant body i.e., cell walls and intercellular spaces. In apoplast pathway, water passes from root hair to xylem through the walls of intervening cells without crossing any membrane or cytoplasm. The pathway provides the least resistance to movement of water. However, it is interrupted by the presence of impermeable lingo-suberin casparian strips in the walls of endodermal cells.

So, the correct answer is 'Both B and C'.

Some carrier proteins allow transport only if two types of molecules move together. This is called cotransport. It is of two types: symport and antiport method. In symport method of cotransport, both molecules cross the membrane in the same direction at the same time. In antiport method of cotransport, both molecules move in opposite direction. When a molecule move across a membrane independent of other molecule, the process is called uniport.

So, the correct answer is 'Symport'.

The diffusion of hydrophilic substances along the concentration gradient through fixed membrane transport proteins without involving energy expenditure, is called facilitated diffusion. Facilitated diffusion is very specific as it allows cell to select substances for uptake. It is sensitive to inhibitors as well as show saturation effect. Two major types of transport proteins are known viz, carrier proteins(also called carriers, transporters) and channel proteins. Carrier proteins bind the particular solute to be transported and deliver the same to the other side of the membrane.

So, the correct answer is 'Facilitated diffusion'.

Active transport is also known as uphill transport that requires the transport of molecules from a low-concentration region to a high-concentration region.  whereas facilitated transport is the passive transport of molecules or ions across a biological membrane via specific transmembrane integral proteins.

So the correct answer is 'Uphill transport'.