Molecular Biology and Genetics

Renaturation is the process in which two complementary DNA strands pair with each other to form a stable double stranded DNA. This process occurs when the melted DNA is cooled. So, the given option is true and it is the correct answer.

When a DNA solution is heated to 90°C or above, there will be enough kinetic energy to denature the DNA completely, causing it to separate into single strands. So, this option is true.

Yes, both the options (2) and (3) actually describe the increased Tm value for some DNAs compared with others.Hence, this option is the correct answer.

A strand of radioactively labelled RNA or DNA, when added to a denatured DNA preparation will act as a probe for DNA molecules to which it is complementary. This hybridisation of complementary strands of nucleic acid is very useful for isolating a specific fragment of DNA from a complex mixture. Hence, this option is the correct answer.

Yes, there are two types of nitrogenous bases, purines and pyrimidines. Hence, this option is the correct answer.

Denatured DNA have less constrained bases compared to stacked bases of double stranded DNA. So, the denatured DNA will show more absorption of light. Hence, this option is the correct answer.

Nucleosides are composed of a five membered pentose carbon sugar (2-deoxyribose sugar in DNA and ribose in RNA) and a nitrogenous base. Hence, this option is the correct answer.

A nucleoside phosphate or a nucleoside with a phosphate group attached at the 5 prime position is called a nucleotide. Hence, this option is the correct answer.

The purine bases are Adenine and Guanine while Cytosine, Uracil and Thymine are pyrimidines. Hence, this option is the correct answer.

Each strand of DNA has both a free 5 prime hydroxyl (OH) group and a free 3 prime OH group at the other end. Hence, this option is the correct answer.

RNA and DNA can be distinguished on the basis of the presence of ribose and uracil in RNA, and deoxyribose and thymine in DNA. Hence, this option is the correct answer.

In DNA, adenine pairs with thymine through 2 hydrogen bonds, while guanine pairs with cytosine through 3 hydrogen bonds. This difference contributes to DNA stability and the melting temperature of the double helix.

DNA is a polymer consisting of many nucleotide monomers linked together in a chain. The prefix 'poly-' means many, referring to the long chain structure of DNA molecules where individual nucleotides are connected by phosphodiester bonds.

tRNA has a characteristic clover leaf secondary structure formed by internal hydrogen bonding between complementary bases. This structure contains the anticodon loop, amino acid attachment site, and other loops essential for its function in translation. The 3D structure is actually L-shaped, but clover leaf is the correct description of the 2D structure.

X-rays, UV rays, mustard gas, nitrous acid, and formaldehyde are all mutagens - agents that cause mutations in DNA. They can induce various types of DNA damage including base modifications, cross-linking, and strand breaks, which lead to mutations during repair or replication. These are examples of induced mutations (as opposed to spontaneous).