Often many ribosomes will read the same message, a structure known as a polysome forms. In this way a cell may rapidly make many proteins. Image from W.H. Freeman and Sinauer Associates, used by permission. The illustration below is from Genentech's Access Excellence site, which may be reeached by clicking here . Addition, deletion, or addition of nucleotides can alter the polypeptide.
Point mutations are the result of the substitution of a single base.
Frame-shift mutations occur when the reading frame of the gene is shifted by addition or deletion of one or more bases. With the exception of mitochondria, all organisms use the same genetic code. Powerful evidence for the common ancestry of all living things. Animated GIF of Translation From the Gene Zine. Amino Acid Anatomy Cartoons and animations on the basics of amino acids.