TLS Online TPP Program

#Question id: 4143


It is possible to convert the Cys that is a part of Cys-tRNACys to Ala by a catalytic reduction.  If the resulting Ala-tRNACys were added to a mixture of (1) ribosomes, (2) all the other tRNAs and amino acids, (3) all of the cofactors and enzymes needed to make protein in vitro, and (4) mRNA for hemoglobin, where in the newly synthesized hemoglobin would the Ala from Ala-tRNACys be incorporated?

#Unit 3. Fundamental Processes
  1. Nowhere; this is the equivalent of a nonsense mutation

  2. Wherever Ala normally occurs

  3. Wherever Cys normally occurs

  4. Wherever either Ala or Cys normally occurs

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TLS Online TPP Program

#Question id: 34160

#Unit 7. System Physiology – Animal

The causes of ACTH-independent Cushing syndrome include following, EXCEPT? 

TLS Online TPP Program

#Question id: 34161

#Unit 7. System Physiology – Animal

Congenital defects in the enzymes lead to deficient cortisol secretion and the syndrome of congenital adrenal hyperplasia. A cause of severe congenital adrenal hyperplasia in newborns is a loss of function mutation of the gene for the: 

TLS Online TPP Program

#Question id: 34162

#Unit 7. System Physiology – Animal

Gonadal and adrenocortical steroids are of following types, EXCEPT? 

TLS Online TPP Program

#Question id: 34163

#Unit 7. System Physiology – Animal

Which of the following represents the correct sequential pathway for aldosterone synthesis from cholesterol, based on the enzyme-catalyzed steps?

TLS Online TPP Program

#Question id: 34164

#Unit 7. System Physiology – Animal

A newborn is diagnosed with 21β-hydroxylase deficiency. Which of the following downstream consequences is most likely due to impaired glucocorticoid production during fetal life?

TLS Online TPP Program

#Question id: 34165

#Unit 7. System Physiology – Animal

Following statements are regarding thyroid hormone biosynthesis?
I. The basolateral membranes of thyrocytes facing the capillaries contain a antiporter that transports two Na+ ions and one I ion into the cell with each cycle, against the electrochemical gradient for I.
II. Na+/I symporter (NIS) is capable of producing intracellular I concentrations that are 20–40 times as great as the concentration in plasma.
III. TSH induces both NIS expression and the retention of NIS in the basolateral membrane, where it can mediate sustained iodide uptake.