A young woman comes to the emergency room with a vertebral compression fracture. Radiographs of the spine indicate generalized demineralization. She is vegetarian, does not smoke or drink alcohol, has normal plasma potassium concentration of 5.4 mEq/L, sodium concentration of 136 mEq/L, plasma calcium concentration is 7.0 mg/dL. Her vitamin D3 value is several times greater than normal, although her 1,25-dihydroxycholecalciferol concentration is at the lower limit of detectability. She has been in renal failure for the last 5 years and undergoes hemodialysis three times each week. What is the cause of her low 1,25-dihydroxycholecalciferol level?

#Question id: 10381

#Unit 6. System Physiology – Plant

symbiosis receptor-like kinase (SYMRK) is another type of receptor involves several function. Which of the following is incorrect?

#Question id: 10382

#Unit 6. System Physiology – Plant

Ureides are

#Question id: 10383

#Unit 6. System Physiology – Plant

The nitrogenase enzyme complex fixes N2 produces ammonia, The nitrogenase enzyme complex catalyzes this reaction by following characteristics given below;

a) It can be separated into two components—the Fe protein and the MoFe protein— neither of which has catalytic activity by itself

b) Fe protein is the smaller of the two components and has two identical subunits, each contains an iron–sulfur cluster, which participates in the redox reactions

c) The Fe protein is irreversibly inactivated by O2 while MoFe protein is activated by O2

d) MoFe protein has four subunits, each subunit has two Mo–Fe–S clusters

e) Ferredoxin serves as an electron donor to the Fe protein, and Fe protein reduces the MoFe protein without any hydrolysing ATP

f) Only prokaryotes have nitrogenase enzyme

Which of the following characteristics of nitrogenase enzyme complex is incorrect?

#Question id: 10384

#Unit 6. System Physiology – Plant

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?

#Question id: 10385

#Unit 6. System Physiology – Plant

The leaves of many species are able to bend toward the sun during its progress across the sky, a phenomenon known as

#Question id: 10386

#Unit 6. System Physiology – Plant

 During light-regulated plant development many seeds require light to germinate, a process called