How many aminoacyl-trna synthetase enzymes must be present in cells to properly synthesize proteins?

a., 3, one for each base in a codon
b., 4, one for each base in the mrna
c., 20, one for each amino acid
d., 64, one for each possible codon

C. 20, one for each amino acid

Explanation:

Aminoacyl-tRNA synthetase is an enzyme involved in protein synthesis (translation) with the role to attach suitable amino acid on its tRNA (amino acid that correspond to the anticodon on tRNA). As a result of its action, aminoacyl-tRNA is formed. There are the 20 different types of aminoacyl-tRNA synthethases that  make 20 different aminoacyl-tRNA one for each amino acid of the genetic code.

a symbiotic relationship with the mitochondria

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.