Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

Meiosis is best observed in dividing microsporocytes.
The male gametophyte is initiated in the flower within anther sacs. Their precursors consist of large cells found in a stacked column near the center of the anther sacs; these cells are known as microsporocytes.
A diploid cell undergoes meiosis to produce microspores as part of microsporogenesis. Also called microspore mother cell pollen mother cell.

The number of organelles required for photorespiration is three.
Photorespiration refers to a process in plant metabolism where the enzyme RuBisCO oxygenates RuBP, wasting some of the energy produced by photosynthesis.
Photorespiration involves a complex network of enzyme reactions that exchange metabolites between chloroplasts, leaf peroxisomes and mitochondria, and these are the three organelles required for this process.

Amylase is an enzyme for which the substrate is Starch.
Amylases digest starch into smaller molecules, ultimately yielding maltose, which in turn is cleaved into two glucose molecules by maltase.
Starch comprises a significant portion of the typical human diet for most nationalities.

Dark reactions of photosynthesis occur in Stroma outside photosynthetic lamellae.
Dark reaction takes place in the stroma (aqueous fluid surrounding the stacks of thylakoids) and the cytoplasm.
The process requires NADPH, which is short-lived and comes from light-dependent reactions. In the dark, plants instead release sucrose into the phloem from their starch reserves to provide energy for the plant.

Dry seeds when placed in water swell up due to Imbibition.
Imbibition is a special type of diffusion that takes place when liquid is absorbed by solids-colloids causing an increase in volume.
Water surface potential movement takes place along a concentration gradient; some dry materials absorb water. A gradient between the absorbent and the liquid is essential for imbibition.

The C₄ cycle is an Adjunct to the Calvin cycle.
C₄ carbon fixation is one of three known photosynthetic processes of carbon fixation in plants.
The CO₂ in C₄ cycle is fixed by RuBisCo to produce phosphoglycerate (PGA) while the pyruvate is transported back to the mesophyll cell, together with about half of the phosphoglycerate.
This PGA is chemically reduced in the mesophyll and diffuses back to the bundle sheath where it enters the conversion phase of the Calvin cycle.

Smut of maize caused by Ustilago maydis.
Corn smut is a plant disease caused by the fungus Ustilago maydis, which attacks corn (maize) and teosinte plants.
The fungus infects all parts of the host plant by invading the ovaries of its host. The infection causes the corn kernels to swell up into tumor-like galls, whose tissues, texture, and developmental pattern are mushroom-like. These galls are made up of hypertrophied cells of the infected plant, along with resulting fungal threads, and blue-black spores.

All the given features about photorespiration are correct except that it is characteristic of C₄ plants. This process does not occur in C₄ plants.
Photorespiration refers to a process in plant metabolism where the enzyme RuBisCO oxygenates RuBP, wasting some of the energy produced by photosynthesis.

Excess of ATP inhibits respiration by inhibiting one of the following enzymes that are Phosphofructokinase.
Low concentrations of ATP inhibited phosphofructokinase activity by decreasing the affinity of the enzyme for the other substrate, fructose 6-phosphate. Citrate, and other intermediates of the tricarboxylic acid cycle, also inhibited the activity of phosphofructokinase.

Respiration is an Exothermic process.
Respiration is the movement of oxygen from the outside environment to the cells within tissues and the removal of carbon dioxide in the opposite direction that's to the environment.
It refers to a metabolic process by which an organism obtains energy (in the form of ATP and NADPH) by oxidizing nutrients and releasing waste products, as energy is released in this process, thus, it is an exothermic process.