In mid-december, a woman with insulin-dependent diabetes who had been on prednisone fell and received an abrasion on the dorsal side of her right hand. she was placed on penicillin. by the end of january, the ulcer had not healed, and she was referred to a plastic surgeon. on january 30, a swab of the wound was cultured at 35°c on blood agar. on the same day, a smear was made for gram staining. the gram stain showed large (10 um) cells. brownish, waxy colonies grew on the blood agar. slide cultures set up on february 1 and incubated at 25°c showed septate hyphae and single conidia. the most likely cause of the infection is a
a) gram-negative bacterium.
b) dimorphic fungus.
c) parasitic alga.
d) yeast.
e) pleomorphic protozoan.

Proteins are the workhorses of the cell, controlling virtually every reaction within as well as providing structure and serving as signals to other cells. proteins are long chains of  amino acids  , and the exact sequence of the amino acids determines the final structure and function of the protein. instructions for that sequence are encoded in  genes  . to make a particular protein, a messenger ribonucleic acid (mrna) copy is made from the gene (in the process called  transcription  ), and the mrna is transported to the  ribosome  . protein synthesis, also called  translation  , begins when the two ribosomal subunits link onto the mrna. this step, called initiation, is followed by elongation, in which successive amino acids are added to the growing chain, brought in by transfer rnas (trnas). in this step, the ribosome reads the  nucleotides  of mrna three by three, in units called  codons  , and matches each to three nucleotides on the trna, called the anticodon. finally, during termination, the ribosome unbinds from the mrna, and the  amino acid  chain goes on to be processed and folded to make the final, functional protein