What does RNA assemble to make proteins?

Short Answer is: amino acids.

The process in which RNA forms Protein is called Translation. The protein is formed on spherical organelles called ribosomes.

Ribosomes have two subunits, each composed of rRNA and proteins, the small unit and large subunit are both composed of Rna. The large subunit has three functional sites, P (peptidyl site), A (amino-acyl site) and the third catalyzes formation of the peptide bonds.

A Codon is a three-base sequence in mRNA that causes the insertion of a particular amino acid into a protein, or termination of translation.

An anti-codon is is a three-base sequence in a tRNA molecule base that pairs with a complementary codon in mRNA. tRNA with specific anticondon can carry a specific type of amino acid. Each amino acid is matched with correct tRNA by enzymes called amino-acyl tRNA synthatase. There is a whole family of these enzymes, one for each amino acid.

The translation completes in these steps: initiation,elongation and translocation.

Initiation: The small ribosomal subunit assembles on start codon AUG.

Elongation: it also has three steps:

(a)Codon recognition: tRNA with anticodon UAC and carrying the amino acid, binds to the codon.The tRNA is in the P site of large ribosomal subunit. The A site is available for the 2nd tRNA with anticodon, complementary to the next codon of m RNA.

(b)Peptide bond formation: The amino acid is carried by the 2nd tRNA and peptide bond is formed between it & new amino acid.

(c)Translocation: The 1st tRNA leaves the P site and 2nd tRNA moves to it, still bound to mRNA. Now the A site is again available for next tRNA. This process of polypeptide chain elongation continues until a stop codon is reached.

Termination: A release factor binds to the A site. It carries no amino acid but facilitate the release of the polypeptide, the ribosome and tRNA from the mRNA.