Question

1. Draw a simple diagram of a prokaryotic ribosome, showing where the mRNA fits and the three grooves/sites inside. Be sure to label each of the subunits with their correct sizes (in S). Then answer the questions below using the diagram and what you know about translation.

a.How does the mRNA know where to bind onto the ribosome?

b.Which factor keeps the ribosomal subunits separate before translation begins? ______

c.Which factor guides the initiator tRNA to the correct site? ______

d.Which site on the ribosome does the first charged tRNA enter? _______

e.What amino acid (remember, we’re in prokaryotes) is it carrying? _______

f.Which site do charged tRNAs normally enter? _______

g.Describe the process of elongation, including which factors are useful for which tasks.

h.Out of which site does the growing polypeptide chain emerge? _______

i.Which codons signal to the ribosome to stop translation? ______ ______ ______

j.What molecule is responsible for “recharging” tRNAs? _________

Answer 1

a. Translation is the process in which a protein is synthesized from the information contained in a molecule of messenger RNA (mRNA). During translation, an mRNA sequence is read using the genetic code, which is a set of rules that defines how an mRNA sequence is to be translated into the 20-letter code of amino acids, which are the building blocks of proteins. The genetic code is a set of three-letter combinations of nucleotides called codons, each of which corresponds with a specific amino acid or stop signal.

b. 3 factor works on prokaryotic translation which is IF-1, IF-2, IF-3.

c. Formylmethionine guide to t-RNA to bind on it.

d. The A site is the point of entry for the aminoacyl tRNA.

i. Codon which stop translation is knwon as termination codon which are UAG, UAA, or UGA.