Nucleic Acids

Q: Both the strand of DNA are not copied during transcription because

Both the strands of DNA are not copied during transcription because if both strands act as a template, they would code for RNA with different sequence the two RNA molecules, if produced simultaneously would be complementary to each other, hence would form a double stranded RNA. Transcription is when RNA is made from DNA. During transcription, RNA polymerase makes a copy of a gene from the DNA to mRNA as needed. This process is similar in eukaryotes and prokaryotes. One difference, however, is that eukaryotic RNA polymerase associates with mRNA processing enzymes during transcription so that processing can proceed quickly after the start of transcription.So, the correct answer is option D.

Q: For the given DNA sequence, the complementary mRNA sequence is given as below \${5}^{\prime} CGTACGTA{3}^{\prime}\$

Messenger RNA is a type of RNA which carries information from the synthesis of protein transcribed from a DNA template. In DNA, there are four different bases: adenine (A), guanine (G), cytosine (C) and thymine (T). Each base has its complementary base, which means in the double helical structure of DNA, A will have T as its complimentary and similarly G will have C. mRNA is formed as a complementary strand to one of the two strands of the DNA. Three of the four nitrogenous bases that make up RNA — adenine (A), cytosine (C), and guanine (G) — are also found in DNA. In RNA, however, a base called uracil (U) replaces thymine (T) as the complementary nucleotide to adenine. This means that during elongation, the presence of adenine in the DNA template strand tells RNA polymerase to attach a uracil in the corresponding area of the growing RNA strand. The mRNA formed will be complimentary to the DNA strand. During transcription RNA polymerase begins moving down the DNA template strand in the 5' to 3' direction, when it does it strings together complementary nucleotides. Because of complementary base- pairing, this action creates a new strand of mRNA that is organized in the 3' to 5' direction. As the RNA polymerase continues down the strand of DNA, more nucleotides are added to the mRNA, thereby forming a progressively longer chain of nucleotides. This process is called elongation. So, the correct answer is option C.

Q: Select the correct match :

TH Morgan discovered the phenomenon of linkage in Drosophila melanogaster.Ribozymes which are also known as ribonucleic acid enzymes are the RNA molecules that can catalyze specific biochemical reactions.G. Mendel who is known as the father of modern genetics, discovered the basic principles of heredity.Cross of F2 with the recessive parent is called test cross.Hence, the correct match is 2. So, the correct answer is option 2.

Q: List three main differences between DNA and RNA ?

DNA (De-oxyribonucleic acid ) RNA (Riboucleic acid)DNA usually exists in the double stranded formRNA predominantly exists in the single-stranded formThe monomeric unit: nucleotide of DNA has Deoxy ribose sugarIt is ribose sugar in RNAIn DNA- Purines; Adenine and Guanine (A and G), Pyrimidines; Thymidine and Cytosine (T and C)In RNA - Purines; Adenine and Guanine (A and G), Pyrimidines; Uracil and Cytosine (U and C)

Q: The 3'-5' phosphodiester linkages inside a polynucleotide chain serve to join

A strand of DNA or RNA consists of nucleotides linked together by phosphodiester bonds. A phosphodiester bond exists between the phosphate of one nucleotide and the sugar 3' carbon of the next nucleotide. This forms a backbone of alternating sugar and phosphate molecules known as the sugar-phosphate backbone.The two strands of DNA are also antiparallel (run in opposite directions) to one another. A strand of DNA can have direction 5'-3' or 3'- 5'.One strand of the DNA molecule is 5'-3' and the other strand is 3'-5'. A DNA strand is assigned direction based on what is found at the end of the strands. The end of the strand with a free phosphate is the 5' end because phosphate attaches to the 5' carbon of the sugar. The end with a free OH group is the 3' end because the OH group is attached to the 3' carbon of the sugar.So, the correct answer is option D.

Q: Which of the following bond is not related to nucleic acid?

A peptide bond is not related to nucleic acid. A peptide bond is a covalent chemical bond formed between two amino acid molecules. The peptide bond is synthesized when the carboxyl group of one amino acid molecule reacts with the amino group of the other amino acid molecule, causing the release of a molecule of water, hence the process is a dehydration synthesis reaction also known as a condensation reaction.So, the correct answer is option D.

Q: Which sugar is present in nucleic acid ____________.

Answer is option A i.e. "Pentose"Nucleic acids are DNA and RNA. The sugar in the DNA molecule is deoxyribose and the one in RNA is ribose sugar. Example of pentose sugar are ribose and deoxyribose sugar.

Q: Which of the following is a purine?

In DNA, the purine bases adenine and guanine form hydrogen bonds with their complementary pyrimidines, thymine, and cytosine, respectively. This is called as a complementary base pairing. So, guanine is a purineSo, the correct answer is 'Guanine'

Q: A nitrogenous base not present in RNA is

The nitrogenous bases are purines and pyrimidines. The purines are adenine and guanine. The pyrimidines are thymine and cytosine. In RNA, the thymine is replaced by uracil. It is mainly found in RNA. It is an ester of phosphoric acid with the nucleoside uridine.So, the correct answer is option B.

Biology

definition

Nucleic acids

Nucleic acids are biopolymers, or large biomolecules, essential for all known forms of life. Nucleic acids include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

definition

Nucleic acid

Nucleic acids are biopolymers, or large biomolecules, essential for all known forms of life.
Nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are made from monomers known as nucleotides.

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