#Question id: 10342
#Botany
Nitrate reductase is an important enzyme for nitrate assimilation. Given below some regulation of nitrate reductase activity through phosphorylation and dephosphorylation.
a) Light, and other environmental factors stimulate a protein phosphatase that dephosphorylates a key serine residue in the hinge 1 region of nitrate reductase and thereby activates the enzyme
b) In Dark, and Mg2+ stimulate a protein kinase that phosphorylates the same serine residues, which then interact with a 14-3-3 inhibitor protein, and thereby inactivate nitrate reductase
c) In Light, and Mg2+ stimulate a protein kinase that phosphorylates the serine residues, and thereby activate nitrate reductase
d) In Dark, and other environmental factors stimulate a protein phosphatase that dephosphorylates a key serine residue in the hinge 1 region of nitrate reductase and thereby inactivates the enzyme
Which of the following statements about regulation of nitrate reductase is correct?
#Question id: 10349
#Botany
Elevated plastid levels of glutamine stimulate the activity of glutamate synthase (also known as glutamine:2- oxoglutarate aminotransferase, or GOGAT). Given below some of the statements about GOGAT, which one of the following is incorrect?
#Question id: 10350
#Botany
Ammonium can be assimilated via an alternative pathway rather than primary pathway which involves the sequential actions of glutamine synthetase(GS) and glutamate synthase(GOGAT), these alternative pathway catalyzes by enzyme known as,
#Question id: 10352
#Botany
which of the following amino acid that participates in the malate–aspartate shuttle to transfer reducing equivalents from the mitochondrion and chloroplast into the cytosol?
#Question id: 10353
#Botany
Aminotransferases are found in multiple organelles such as cytoplasm, chloroplasts, mitochondria, glyoxysomes, and peroxisomes, these aminotransferases one of its organelles may have a significant role in amino acid biosynthesis such as;
#Question id: 10354
#Botany
One of the enzyme that are involve in the ammonium assimilation is Asparagine synthetase (AS), some statements given below about AS such as,
a) This enzyme that catalyzes this reaction, is found in the cytosol of leaves and roots and in nitrogen-fixing nodules
b) High levels of light and carbohydrate inhibit the expression of genes coding for AS and the activity of the enzyme
c) Conditions of ample energy stimulate AS, thus they favor nitrogen assimilation into glutamine and glutamate
d) Energy-limited conditions inhibit GS and GOGAT, stimulate AS, and thus favor nitrogen assimilation into asparagine, a compound that is rich in nitrogen and sufficiently stable for long-distance transport or long term storage
Which of the following statements about AS is correct?