11. DNA replication takes place in which direction?

A. 3′ to 5′
B. 5 ‘to 3’
C. Randomly
D. Vary from organism to organism

12. DNA gyrase in E. coli

A. adds positive supercoils to chromosomal DNA
B. can be inhibited with antibiotics
C. is required only at the oriC site
D. performs the same function as helicase in eukaryotes

13. In DNA, there are

A. five bases known as adenine, guanine, thymine, tryptophan and cytosine
B. four bases known as adenine, guanine, thymine and cytosine
C. three bases known as adenine, guanine and cytosine
D. only two bases known as adenine and cytosine

14. In DNA, guanine pairs with

A. Adenine
B. Cytosine
C. Thymine
D. Uracil

15. Which of the following is incorrect?

A. In DNA double helix, two strands of the DNA are bound with each other with the bases
B. Adenine always pairs with thymine
C. Guanine always pairs with the cytosine
D. None of the above