Biology

Molecular Biology and Genetics

717 Questions

Molecular biology and genetics explore the structure and function of DNA, RNA, genetic mutations, and heredity. Understanding these building blocks of life is essential for most biology examinations. Review these practice questions to test your molecular genetics knowledge.

DNA structure and basesGenetic mutationsNucleic acids compositionDNA sequencing and replication

Molecular Biology and Genetics Questions

Multiple choice

Which component of the HAT medium blocks the cellular biosynthesis of purines and pyrimidines from simple sugars and amino acids?

HAT medium is one of the several selective media used for the selection of hybrid cells.This medium is supplemented with hypoxanthine , aminopterin and thymidine and hence the name HAT medium. Only cell lines expressing both hypoxanthine phosphoribosyl transferase (HPRT+) and thymidine kinase (TK+) can survive in this medium.

  1. Aminopterin

  2. Hypoxanthine

  3. Thymidine

  4. Both 2 and 3

  5. Rayon acetate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The antimetabolite aminopterin blocks the cellular biosynthesis of purines and pyrimidines from simple sugars and amino acids while HGPRT and TK supply them from hypoxanthine and thymidine.

Multiple choice

RNA is considered as the first genetic material to have evolved on the earth. Which one of the following properties of RNA is critical for its functioning as the genetic material in the absence of DNA and protein?

  1. The presence of uracil as a base in place of thymine

  2. The RNA is less stable than DNA; therefore RNA has higher probability to evolve as genetic material as compared to DNA

  3. The single stranded RNA has a genotype as well as phenotype

  4. RNA exists in 3 forms while DNA has only one form
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice plant kingdom biology

Choose the correct statement.

  1. Haploid contained of human DNA is4.6$\times{10}^6$bp

  2. A nitrogenous base is linked to pentose sugar through phosphodiester linkage

  3. X-ray diffraction data of Maurice Wilkins and Rosalind Franklin was the basis of Watson and Crick's DNA model

  4. DNA is an acidic substance was first identified by Watson and Crick
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice biology meaning of life chemical organization in living beings lipids proteins and their structure

In which one of the following combinations, the compounds are arranged in ascending order based on their molecular weights?

  1. DNA, RNA, AMP, ADP, ATP

  2. DNA, RNA, ATP, ADP, AMP

  3. AMP, ADP, ATP, RNA, DNA

  4. AMP, ATP, ADP, DNA, RNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Molecular weights increase from AMP (monophosphate) to ADP (diphosphate) to ATP (triphosphate). RNA and DNA are polymers of nucleotides and thus have significantly higher molecular weights than individual nucleotides.

Multiple choice botany biotechnology: principles and processes downstream processing biotechnology biotechnology and its application

Purines possess nitrogen at

  1. 1, 2, 4 and 6 positions

  2. 1, 3, 5 and 7 positions

  3. 1, 3, 7 and 9 positions

  4. 1, 2, 6 and 8 positions
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Purines are heterocyclic aromatic organic compounds. In the purine ring structure (a fused pyrimidine and imidazole ring), the nitrogen atoms are located at positions 1, 3, 7, and 9.