ICSE Class 10 Answered

46.

Messenger RNA (mRNA) molecules carry the coding sequences for protein synthesis and are called transcripts.

Ribosomal RNA (rRNA) molecules form the core of a cell's ribosomes (the structures in which protein synthesis takes place).

Transfer RNA (tRNA) molecules carry amino acids to the ribosomes during protein synthesis. 

Since amino acids were not carried to the site of protein synthesis from the amino acid pool, the bacteria were unable to synthesize proteins. This implies that the process lacked t-RNA to transport or transfer the amino acids to the translation site.

So, the correct answer is option C.

47.

For every three molecules of CO₂ that enters the Calvin cycle, one molecule of the three carbon glyceraldehyde 3-phosphate (G3P) is produced.

A G3P molecule contains three fixed carbon atoms. Therefore, two molecules of G3P are needed to build one molecule of six-carbon glucose.

Therefore, the Calvin cycle needs to make a total of 6 turns to produce two molecules of G3P.

One turn of the Calvin cycle requires 3 molecules of ATP and 2 molecules of NADPH.

So for 6 turns:

3 ATP x 6 = 18 ATPs

2 NADPH x 6 = 12 NADPHs

So, the correct answer is option C.