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Nucleic acids: nucleotides, DNA and RNA

46 questions on Nucleic acids: nucleotides, DNA and RNA from the Biomolecules chapter: 8 NEET level, 19 JEE Main, 19 JEE Advanced. Each one opens with its answer and solution.

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A nucleotide is made up of NEET level
The sugar present in DNA is NEET level
Which base is present in RNA but not in DNA? NEET level
In the DNA double helix, adenine pairs with thymine through how many hydrogen bonds? NEET level
Which of the following is a purine base? NEET level
Which statement correctly distinguishes RNA from DNA? JEE Main level
The genetic code is read in groups of bases. There are 4 different bases and 20 amino acids to be coded. What is the smallest number of bases per codon that can... JEE Main level
A DNA strand has the sequence 5^prime-ATGCCA-3^prime. The complementary strand, written from its 5^prime end to its 3^prime end, is JEE Main level
In a DNA strand, adjacent nucleotides are joined by a phosphodiester bond between JEE Main level
In a nucleoside, the nitrogenous base is attached to the pentose sugar through an N-glycosidic bond at which carbon of the sugar? JEE Main level
Bacterial DNA labelled with ^15N in both strands is allowed to replicate semi-conservatively for exactly two rounds in a medium containing only ^14N. The four r... JEE Main level
Which set correctly assigns functions to the three types of RNA? JEE Main level
Among the following double-stranded DNA fragments (each 6 base pairs, one strand shown 5^prime to 3^prime), which has the highest melting temperature? (Use hydr... JEE Main level
A coding region of mRNA is 300 nucleotides long and ends with one stop codon that codes for no amino acid. Assuming it starts at the first nucleotide and is rea... JEE Main level
A double-stranded DNA contains the strand 5^prime-GATTACAGC-3^prime fully paired with its complementary strand. Taking A-T pairs to have 2 hydrogen bonds and G-... JEE Main level
Select the correct statements about the DNA double helix. JEE Main level
A double-stranded DNA of 1000 base pairs (2000 bases in all) has 30% adenine of the total bases. Taking A-T = 2 and G-C = 3 hydrogen bonds per pair, the total n... JEE Advanced level
The template strand of a gene is 3^prime-TACCGATTCACT-5^prime. mRNA is transcribed from it. Translation begins at the first AUG and ends at a stop codon (UAA, U... JEE Advanced level
A linear double-stranded DNA is 12 base pairs long, with one strand 5^prime-GCGAATTCGCGC-3^prime. Count each phosphodiester bond in both strands (A-T = 2 and G-... JEE Advanced level
A bacterial DNA is grown for many generations in ^15N medium, so both strands are heavy. It is then moved to ^14N medium and allowed to replicate semi-conservat... JEE Advanced level
Two 20-base-pair DNA duplexes are compared. Duplex P has 35% G-C pairs and duplex Q has 65% G-C pairs (A-T = 2 and G-C = 3 hydrogen bonds). Which statement is c... JEE Advanced level
The molecule adenosine 5^prime-triphosphate (ATP) contains how many phosphoanhydride (P-O-P) linkages, and which sugar? JEE Advanced level
One strand of a double-stranded DNA has the composition 23% A, 29% T, 27% G and 21% C (of the bases in that strand). What is the percentage of adenine among all... JEE Advanced level
Select the correct statements. JEE Advanced level
A DNA duplex has one strand 5^prime-ATGCGC-3^prime paired with its complementary strand. Select the correct statements. (A-T = 2 and G-C = 3 hydrogen bonds.) JEE Advanced level
An mRNA is 5^prime-AUGGCAUUCUAA-3^prime, where UAA is a stop codon. Select the correct statements. JEE Advanced level
Which of the following base compositions (percent of total bases) can belong to a double-stranded DNA? JEE Advanced level
A nucleoside consists of NEET level
The two purine bases found in nucleic acids are NEET level
In double-stranded DNA, adenine pairs with thymine through NEET level
The sugar in DNA, 2-deoxyribose, differs from ribose in lacking the hydroxyl group on carbon JEE Main level
A double-stranded DNA sample contains 28% adenine by number of bases. According to Chargaff's rules, the percentage of guanine is JEE Main level
A DNA duplex has one strand 5-prime ATGCGCATTAGC 3-prime paired with its complementary antiparallel strand. Count two hydrogen bonds for each A-T pair and three... JEE Advanced level
A double-stranded DNA segment has 10 base pairs, of which 4 are A-T pairs and 6 are G-C pairs. Count two H bonds per A-T pair and three per G-C pair, and phosph... JEE Advanced level
The complementary strand of 5-prime ATGCCG 3-prime, written in the 5-prime to 3-prime direction, is JEE Main level
An mRNA coding region is exactly 306 nucleotides long, running in frame from the start codon AUG to the final stop codon UAA, both included. Assuming the start ... JEE Main level
Four DNA samples have G + C content of 30%, 38%, 45% and 60%. Which sample has the highest melting temperature, and why? JEE Main level
Assertion (A): RNA is hydrolysed readily by dilute alkali, whereas DNA is stable under the same conditions. Reason (R): Ribose in RNA has a 2-prime hydroxyl gro... JEE Main level
Match the nucleic acid in List I with its role in List II. List I: (P) DNA; (Q) mRNA; (R) tRNA; (S) rRNA. List II: (1) carries a specific amino acid to the ribo... JEE Main level
A double-stranded DNA of 1000 base pairs contains 30% adenine (percentages are of all 2000 bases). Count two hydrogen bonds per A-T pair and three per G-C pair.... JEE Advanced level
Which statements are correct? JEE Advanced level
In a double-stranded DNA the ratio (A + T)/(G + C) is 1.5. The percentage of guanine is JEE Main level
One strand of a double-stranded DNA has the composition A 24%, T 32%, G 26%, C 18%. Using strand complementarity, the overall percentage of guanine in the doubl... JEE Advanced level
The template strand 3-prime TACGGATTCATT 5-prime is transcribed into mRNA. Read the mRNA from its 5-prime end in non-overlapping codons, with UAA, UAG and UGA a... JEE Advanced level
Which statements are correct? JEE Advanced level
The dinucleotide 5-prime ApU 3-prime (ribose in both) has a free 5-prime OH and a free 3-prime OH, with one phosphodiester linkage from the 3-prime oxygen of th... JEE Advanced level