Plant Pathology - Study Mode

[#106] Which one of the following microbial agents is being commercially exploited as biocontrol agent
Correct Answer

(D) Trichoderma viride

Explanation

Solution: Trichoderma viride is the microbial agents that that is being commercially exploited as biocontrol agent. Trichoderma viride is a fungus and a biofungicide. It is used for seed- and soil treatment for suppression of various diseases caused by fungal pathogens. The fungicidal activity makes T. viride useful as a biological control against plant pathogenic fungi. It has been shown to provide protection against such pathogens as Rhizoctonia, Pythium and even Armillaria.

[#107] The carbon dioxide acceptor in Calvin cycle/C 3 -plants is
Correct Answer

(B) Ribulose 1, 5-diphosphate (RuBP)

Explanation

Solution: The carbon dioxide acceptor in Calvin cycle/C 3 -plants is Ribulose 1, 5-diphosphate (RuBP). Ribulose 1,5-bisphosphate (RuBP) is an organic substance that is involved in photosynthesis, notably as the principal CO 2 acceptor in plants. It is a colourless anion, a double phosphate ester of the ketopentose (ketone-containing sugar with five carbon atoms) called ribulose. The enzyme ribulose-1,5-bisphosphate carboxylase-oxygenase (rubisco) catalyzes the reaction between RuBP and carbon dioxide.

[#108] Photorespiration occurs in
Correct Answer

(A) Green parts

Explanation

Solution: Photorespiration occurs in Green parts. Photorespiration refers to a process in plant metabolism where the enzyme RuBisCO oxygenates RuBP, wasting some of the energy produced by photosynthesis. Photorespiration may be necessary for the assimilation of nitrate from soil. Lowering photorespiration may not result in increased growth rates for plants. Thus, a lowering in photorespiration by genetic engineering or because of increasing atmospheric carbon dioxide.

[#109] Type II Secretion system is common in bacteria which are
Correct Answer

(B) Gram negative

Explanation

Solution: Type II Secretion system is common in bacteria that are Gram negative. The type 2 secretion system is a type of protein secretion machinery found in various species of Gram-negative bacteria, including many human pathogens such as Pseudomonas aeruginosa and Vibrio cholerae. The type II secretion system enables the transport of cytoplasmic proteins across the lipid bilayers that make up the cell membranes of Gram-negative bacteria. Many Gram-negative bacteria use the type II secretion system to translocate folded proteins from the periplasm, through the outer membrane, into the extracellular milieu.

[#110] Match the following columns: Column I (Bacteria) Column II (Function) a. Nitrobacteria 1. Fixation of atmospheric nitrogen b. Ammonifying bacteria 2. Formation of NH 4 + nitrogen c. Denitrifying bacteria 3. Formation of NO 3 - nitrogen d. Rhizobium sp. 4. Formation of N 2 nitrogen
Correct Answer

(C) a-3, b-2, c-4, d-1

Explanation

Solution: Nitrobacteria are obligate aerobes. It plays an important role in the nitrogen cycle by oxidizing nitrite (NO 3 - ) into nitrate and ultimately nitrogen in the soil. Ammonifying bacteria convert ammonia into atmospheric nitrogen. Denitrifying bacteria results in the conversion of nitrates in the soil to free atmospheric nitrogen.
Rhizobium species are a group of bacteria that helps in fixing atmospheric nitrogen in plants.