Griffith's experiment worked with two types of pneumococcal bacteria (a rough type and a smooth type) and identified that a "transforming principle" could transform them from one type to another.
At first, bacteriologists suspected the transforming factor was a protein. The "transforming principle" could be precipitated with alcohol, which showed that it was not a carbohydrate. But Avery and McCarty observed that proteases (enzymes that degrade proteins) did not destroy the transforming principle. Neither did lipases (enzymes that digest lipids). Later they found that the transforming substance was made of nucleic acids but ribonuclease (which digests RNA) did not inactivate the substance. By this method, they were able to obtain small amounts of highly purified transforming principle, which they could then analyze through other tests to determine its identity, which corresponded to DNA.
4: a species is a group of interbreeding natural populations that are reproductively isolated from other such groups. Process of Speciation. The process of speciation is a 2 stage process in which reproductive isolating mechanisms arise between groups of populations.
Answer:
transcription of mRNA from DNA
small ribosomal subunit binds to mRNA
initiation complex formed with addition of large ribosomal subunit
translocation
codon recognition (non-initiating site)
peptide bond formation
ribosome reads a stop codon
polypeptide chain is released from the P site
ribosomal subunits dissociate
Explanation:
The above describes the process of translation in the ribosome. After transcription of DNA to mRNA, the mRNA is taken to the ribosome to undergo translation, here the mRNA binds to the small ribosomal subuits and to other initiation factors; binding at the mRNA binding site on the small ribosomal subunit then the Large ribosomal subunits joins in.
Translation begins (codon recognition; initiating site) at the initiation codon AUG on the mRNA with the tRNA bringing its amino acid (methionine in eukaryotes and formyl methionine in prokaryotes) forming complementary base pair between its anticodon and mRNA's AUG start codon. Then translocation occurs with the ribosome moving one codon over on the mRNA thus moving the start codon tRNA from the A site to the P site, then codon recognition occurs (non-initiating site again) which includes incoming tRNA with an anticodon that is complementary to the codon exposed in the A site binds to the mRNA.
Then peptide bond formation occurs between the amino acid carried by the tRNA in the p site and the A site. When the ribosome reads a stop codon, the process stops and the polypeptide chain produced is released and the ribosomal subunits dissociates.
