In: Biology
Answer a.
Assuming two disconnected processes, i.e., no simultaneous
occurrence of transcription and translation on the same elongating
transcript, we see that 550 amino acids posses 550 * 3 = 1650
nucleotides coding transcript, because each 3 nucleotides make 1
codon encoding for 1 amino acid.
Processing 1650 nucleotides takes 1650 / {(40+80)/2} = 27.5
seconds.
Following which 550 amino acids, will take 550/20 = 27.5 seconds
more.
In total, the time taken will be 27.5 + 27.5 = 55 seconds
Answer b.
If transcription occurred more rapidly than translation, then many
mRNA transcripts will accumulate in the transcriptome, and by the
time their proteins are translated, there would be a significant
delay in feedback regulated processes, both for repressors and
inducers.
If the translation occurs more rapidly than transcription then that
is wasteful machinery with too many parts dedicated to the end
product because the bottleneck step will always be the precursor
transcription step, forming transcripts at a much slower rate than
their protein products.
Answer c.
There are many reasons for translation being much slower in complex
organisms such as eukaryotes, such as the presence of introns
requiring post-processing to obtain a functional mRNA molecule
before it can go for translation. Apart from that, we have quite a
large variety of alternatively spliced mRNA transcripts, which
further increases the pool of mRNA's as opposed to their protein
products.
Also, eukaryotes have monocistronic genes which means each gene
codes for one polypeptide unlike prokaryotes, that further adds a
large pool of mRNA transcripts. This diversity implies that we need
much faster transcription speeds than translation speeds.