Classify each element as an alkali metal, alkaline earth

1. Three types of RNA are involved in protein synthesis: transfer RNA (tRNA), messenger RNA (mRNA) and ribosomal RNA (mRNA). mRNA serves as the template (instructions) to make the protein. Recall that the mRNA was produced from the original DNA gene that contained the instructions to make the protein. rRNA makes up the physical structure of the ribosome itself. There are about 45 different types of tRNA molecules, each capable of binding to a specific amino acid. Each one contains an anticodon(the complement of a codon) on one end and the corresponding amino acid on the other end. For example, if an mRNA codon is UUU, the corresponding tRNA anticodon will be AAA. 2. The ribosome is more than just a passive attachment site for mRNA and tRNA. Besides its binding site for mRNA, there are three binding sites for tRNA; an A site for the incoming tRNA molecule, a P site for the tRNA holding the growing protein chain and an E site for the outgoing tRNA. The ribosome holds the tRNA and mRNA closely together to coordinate the coupling of codons and anticodons and positions the incoming amino acid for addition to the growing polypeptide chain. 3. Transcription is the process whereby mRNA is copied from a gene on the DNA. This process involves the breaking part of the DNA segment where transcription is to take place (unzipping). One by one, each triplet on the DNA template is copied into a corresponding mRNA codon. This process is directed by the