The term modified base refers to

A. Purine or pyrimidine attached to deoxyribose

B. A purine or pyrimidine that has been altered

C. A nitrogen containing ring other than a purine or pyrimidine that is part of a nucleotide

D. A purine or pyrimidine attached to a sugar by O-glycoside linkage

Correct Answer: A purine or pyrimidine that has been altered

Description: A modified base is one that has been modified after nucleic acid chain has been formed. These bases are modified by methylation, reduction, acetylation or glycosylation. In t-RNA there are many modified bases, e.g. dihydrouridine, ribothymidine, pseudouridine, and 7-methylguanosine. In DNA, the most common modified base is 5-methylcytosine. Other important modified bases are acetylcytosine and dimethyladenine.

Category: Biochemistry

Share:

← Previous MCQ

Next MCQ →

Get More

Subject Mock Tests

Practice with over 200,000 questions from various medical subjects and improve your knowledge.

Attempt a mock test now

Mock Exam

Take an exam with 100 random questions selected from all subjects to test your knowledge.

Coming Soon

Get More

Subject Mock Tests

Try practicing mock tests with over 200,000 questions from various medical subjects.

Attempt a mock test now

Mock Exam

Attempt an exam of 100 questions randomly chosen from all subjects.

Coming Soon