NEET Practice Questions (MCQs) with Answers & Solutions

The text explains: 'Cell membrane and other membranes are broken into pieces, and form vesicles which are not water soluble. Therefore, these membrane fragments in the form of vesicles get separated along with the acid insoluble pool and hence in the macromolecular fraction. Lipids are not strictly macromolecules.'

According to the NCERT text, 'Nucleic acids are the polymers of nucleotides which in turn consist of a base, a pentose sugar and phosphate moiety.' Additionally, another section states, 'A nucleotide has three chemically distinct components. One is a heterocyclic compound, the second is a monosaccharide and the third a phosphoric acid or phosphate.'

The NCERT text states, 'DNA contains a five carbon sugar molecule called 2-deoxyribose whereas RNA contains ribose.' More specifically, 'In DNA molecules, the sugar moiety is $\beta$-D-2-deoxyribose whereas in RNA molecule, it is $\beta$-D-ribose.'

The NCERT text clearly states, 'RNA also contains four bases, the first three bases are same as in DNA but the fourth one is uracil (U).' It further adds, 'The fourth base is thymine in DNA and uracil in RNA.'

The NCERT states, 'A unit formed by the attachment of a base to 1¢ position of sugar is known as nucleoside.' Another part specifies: 'A nitrogenous base is linked to the OH of 1' C pentose sugar through a N-glycosidic linkage to form a nucleoside.'

The NCERT text mentions, 'Nucleotides are joined together by phosphodiester linkage between 5¢ and 3 carbon atoms of the pentose sugar.'

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.'

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.'

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.'

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.'