Practice free Chemistry NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
According to Chargaff's rule for double-stranded DNA, which of the following ratios is constant and equals one?
The NCERT text states, 'this proposition was also based on the observation of Erwin Chargaff that for a double stranded DNA, the ratios between Adenine and Thymine and Guanine and Cytosine are constant and equals one.'
What is the primary function of DNA in the cell?
The NCERT text explicitly states, 'DNA is the chemical basis of heredity and have the coded message for proteins to be synthesised in the cell.'
Identify the type of nitrogenous base that classifies Adenine and Guanine.
The NCERT text states, 'There are two types of nitrogenous bases – Purines (Adenine and Guanine), and Pyrimidines (Cytosine, Uracil and Thymine).Adenine and Guanine are substituted purines while the rest are substituted pyrimidines.'
In the double helix structure of DNA, where are the hydrogen bonds formed?
The NCERT text describes, 'Two nucleic acid chains are wound about each other and held together by hydrogen bonds between pairs of bases.' It further clarifies, 'Adenine forms hydrogen bonds with thymine whereas cytosine forms hydrogen bonds with guanine.'
Which of the following is NOT a type of RNA molecule mentioned in the context?
The NCERT text lists, 'RNA molecules are of three types and they perform different functions. They are named as messenger RNA (m-RNA), ribosomal RNA (r-RNA) and transfer RNA (t-RNA).' snRNA is not mentioned.
Friedrich Meischer identified DNA as an acidic substance in the nucleus in 1869 and named it:
The NCERT text states, 'DNA as an acidic substance present in nucleus was first identified by Friedrich Meischer in 1869. He named it as 'Nuclein'.'
A nucleotide differs from a nucleoside by the presence of a:
The NCERT text states, 'When found attached to a sugar, they are called nucleosides. If a phosphate group is also found esterified to the sugar they are called nucleotides.' This indicates that the phosphate group is the differentiating factor.
The sequential information regarding the order of nucleotides in a nucleic acid chain is known as its:
The NCERT text defines this as, 'Information regarding the sequence of nucleotides in the chain of a nucleic acid is called its primary structure.'
What is the typical structure of RNA molecules as described in the context?
The NCERT text contrasts RNA with DNA: 'In secondary structure of RNA single stranded helics is present which sometimes foldsback on itself.' It also mentions, 'The structure of DNA is a double strand whereas RNA is a single strand molecule.'
Which carbon atom of the sugar moiety in a nucleoside is numbered 1'?
The NCERT states, 'A unit formed by the attachment of a base to 1¢ position of sugar is known as nucleoside. In nucleosides, the sugar carbons are numbered as 1¢, 2¢, 3¢, etc. in order to distinguish these from the bases.'
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