11. Which of the following is NOT anon-covalent bond that gives form to proteins ?
(A) H-bond    (B) ionic bond (C) disulfidebridge     (D) van der Waalsinteractions
12. Which of the following would preventtranscription of the lactose operon?
(A) lactose      (B) allolactose(C) tryptophan           (D) glucose
13. Which of the following would preventtranscription of the tryptophan operon?
(A) lactose      (B) allolactose           (C) tryptophan           (D) glucose