Dear Students,
Welcome to Plant Physiology MCQ-05. This MCQ set consists of Advanced (PG Level) Plant Physiology for CSIR NET Questions with Answer Key taken from the previous year question papers of CSIR NET Life Sciences Examination. These questions can be used for the preparation of Competitive examinations in Biology / Life Sciences such as CSIR JRF NET, ICMR JRF, DBT BET JRF, GATE and other University Ph.D Entrance Examinations.
You may also like: Plant Physiology Notes | Plant Physiology PPT
(1). Nitrogen fixation is basically a process of converting nitrogen gas into ammonia (NH3). One of the key enzymes in the process is ‘nitrogenase’. The production and activity of nitrogenase is very highly regulated as highlighted below:
(A). Nitrogen fixation through nitrogenase is an energetically expensive process.
(B). Nitrogenase encoding gene is under a constitutive promoter
(C). Nitrogenase is highly sensitive to oxygen
(D). Endogenous availability of the cofactor of nitrogenase enzyme is very low
Which one of the following combinations of above statements is correct? (CSIR_2015_I)
(a). (A) and (B)
(b). (A) and (C)
(c). (B) and (C)
(d). (B) and (D)
Ans. (b)
(2). The amount of each enzyme present in the chloroplast stroma is regulated by mechanisms that control the concerned expression of nuclear and chloroplast genomes. Following are certain statements regarding the regulation of chloroplast enzymes:
(A). Nucleus-encoded enzymes are translated on 70S ribosomes in the cytosol and subsequently transported into the plastid
(B). Plastid encoded enzymes are translocated in the stroma on prokaryotes-like 70S ribosomes
(C). Light modulates the expression of stromal enzymes encoded by the nuclear genome via specific photoreceptors.
(D). The eight small subunits of RUBISCO is encoded in plastid
Which one of the following combinations of above statements is correct? (CSIR_2015_I)
(a). (A) and (B)
(b). (A) and (C)
(c). (B) and (C)
(d). (C) and (D)
Ans. (c)
(3). Aquaporins are a class of proteins that are relatively abundant in the plant membranes. Following are certain statements regarding the properties of aquaporins:
(A). Aquaporins form water channels in membrane
(B). Some aquaporins also transport uncharged molecules such as NH3
(C). The activity of aquaporins is not regulated by phosphorylation
(D). The activity of aquaporin is regulated by calcium concentration and reactive oxygen species.
Which one of the following combinations of above statements is correct? (CSIR_2015_I)
(a). (A), (B) and (D)
(b). (B), (C) and (D)
(c). (A), (C) and (D)
(d). (a), (B) and (C)
Ans. (c)
(4). Phenylalanine, a precursor of most of the phenolics in higher plants is a product of which one of the following pathways? (CSIR_2015_II)
(a). Shikimic acid pathway
(b). Malonic acid pathway
(c). Mevalonic acid pathway
(d). Methylerythritol pathway
Ans. (a)
(5). For which one of the following physiological studies 12CO2 and 13CO2 are used? (CSIR_2015_II)
(a). Estimate the rate of photosynthesis
(b). Determine rate of photorespiration
(c). The ratio of C4 and CAM pathways of CO2 fixation
(d). The ratio of C3 and C4 pathways of CO2 fixation
Ans. (d)
(6). Gibberellic acid (GA) controls seed germination by directing breakdown of the stored starch. In which one of the following tissues of the barley seed, α-amylase gene is induced in response to GA? (CSIR_2015_II)
(a). Endosperm
(b). Coleoptile
(c). Aleurone layer
(d). Embryo
Ans. (c)
(7). The photosynthetic assimilation of atmospheric CO2 by leaves yield sucrose and starch as end products of two gluconeogenic pathways that are physically separated. Which one of the following combination of cell organelles are involved in such physical separation of the process? (CSIR_2015_II)
(a). Sucrose in cytosol and starch in mitochondria.
(b). Sucrose in chloroplasts and starch in cytosol.
(c). Sucrose in mitochondria and starch in cytosol.
(d). Sucrose in cytosol and starch in chloroplasts.
Ans. (d)
(8). Following are certain statements regarding terpene class of secondary metabolites in plants:
(A). Isopentenyl diphosphate and its isomer combine to form larger terpenes.
(B). Diterpenes are 20 carbon compounds.
(C). All terpenes are derived from the union of 4-carbon elements.
(D). Pyrethroids are monoterpene esters.
Which one of the following combination of above statements is correct? (CSIR_2015_II)
(a). A, B and C
(b). A, B and D
(c). B, C and D
(d). A, C and D
Ans. (b)
(9). Which one of the following is the correct order of electron transport during light reaction in the thylakoid membrane of chloroplast? (CSIR_2016_I)
(a). P680 → Cytochrome b6f → PC → PQ
(b). P680→ PC → Cytochrome b6f → PQ
(c). P680→ PQ → PC → Cytochrome b6 f
(d). P680→ PQ → Cytochrome b6f → PC
Ans. (d)
(10). The following statements are made to describe auxin signal transduction pathway, from receptor binding to the physiological response:
(A). Auxin response factors (ARFs) are nuclear proteins that bind to auxin response elements (Aux REs) to activate or repress gene transcription.
(B). AUX/IAA proteins are secondary regulators of auxin-induced gene expression. Binding of AUX/IAA proteins to the ARF protein blocks its transcription regulation.
(C). Auxin binding to TIR1/AFB promotes ubiquitin-mediated degradation and removal of AUX/IAA proteins.
(D). Auxin binding to auxin response factors (ARFs) causes their destruction by the 26S proteasome pathway.
Which one of the following combinations of above statements is correct? (CSIR_2016_I)
(a). A, B and C
(b). A, C and D
(c). B, C and D
(d). A, B and D
Ans. (d)