TLS Online TPP Program

#Question id: 129


Glycine is not a stereoisomer because

#Life Sciences
  1. it has no chiral carbon.

  2. it does not form enantiomers.

  3. it does not exist in two non-superimposable mirror-image forms.

  4. All of the above

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TLS Online TPP Program

#Question id: 10368

#Environmental Science

Free-living bacteria that are capable of fixing nitrogen are aerobic, facultative, or anaerobic. Some of the Aerobic nitrogen-fixing bacteria such as

TLS Online TPP Program

#Question id: 10369

#Environmental Science

Which type of the nitrogen-fixing bacteria are thought to maintain a low oxygen concentration (microaerobic conditions) through their high levels of respiration

TLS Online TPP Program

#Question id: 10376

#Environmental Science

Symbiotic nitrogen-fixing rhizobia release nodulation (Nod) factors as signaling agents as they near the surface of a legume root. The interaction between specific nod factors and their corresponding receptors. Which of the following statements is incorrect?

TLS Online TPP Program

#Question id: 10384

#Environmental Science

Nitrogenase enzyme complex catalyzes the molecular nitrogen fixation, this enzyme not only fixes nitrogen but also perform other reactions given below. Which one is not performed by nitrogenase?

TLS Online TPP Program

#Question id: 10334

#Environmental Science

N2 combines with hydrogen to form ammonia under elevated temperature (about 200°C) and high pressure (about 200 atmospheres) and in the presence of a metal catalyst (usually iron). The extreme conditions are required to overcome the high activation energy of the reaction. This nitrogen fixation reaction, called

TLS Online TPP Program

#Question id: 10342

#Environmental Science

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?