11. The lac operon contains the z, y and a structural genes
A. encoding p-galactosidase, galactose permeases and thio-galactosidase transacetylase respectively
B. encoding p-galactosidase and galactose permeases
C. encoding P-galactosidase only
D. None of the above
12. Proteins contain __________ different amino acids, whereas DNA and RNA are composed of __________ different nucleotides
A. 20,64
B. 3,20
C. 4,20
D. 20,4
13. Which of the following is not necessary for protein synthesis to occur, once transcription is completed?
A. tRNA
B. Ribosomes
C. mRNA
D. DNA
14. Ribosomes select the correct tRNAs
A. then bind to the appropriate mRNA
B. solely on the basis of their anticodons
C. depending on their abundance in the cytosol
D. with the least abundant anticodons
15. Signal peptide protein removal that is translocated across a membrane is accomplished by
A. fMet aminopeptidase
B. trypsin
C. signal peptidase
D. chymotrypsin