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THE CHEMICAL NATURE OF RNA DIFFERS FROM THAT OF DNA

.Note that: the sequence in the RNA transcript is the same as that in the coding strand, except that

the U of the transcript replaces the T of the gene

the initiating nucleotide of RNAs contain a triphosphate (ie, pppA-above).However, given the proper complementary base sequence with opposite polarity, the single strand of RNA is capable of folding back on itself like a hairpin and thus acquiring double-stranded characteristics: G pairing with C, and A pairing with U.

The RNA transcript with a 5' to 3' is complementary to the template strand with its 3' to 5' polarity.Since the RNA molecule is a single strand complementary to only one of the two strands of a gene, its guanine content does not necessarily equal its cytosine content, nor does its adenine content necessarily equal its uracil content.In RNA, the sugar moiety to which the phosphates and purine and pyrimidine bases are attached is ribose rather than the 2'-deoxyribose of DNA.UNIVERS MANSOURA

SAMSUNG

The pyrimidine components of RNA can differ from those of DNA..terminal 5-

THE CHEMICAL NATURE OF RNA DIFFERS FROM THAT OF DNA

. In RNA, the sugar moiety to which the phosphates and purine and pyrimidine bases are attached is ribose rather than the 2'-deoxyribose of DNA.

UNIVERS MANSOURA

SAMSUNG

The pyrimidine components of RNA can differ from those of DNA. Although RNA contains the ribonucleotides of adenine, guanine, and cytosine, it does not possess thymine except in the rare case mentioned below. Instead of thymine, RNA contains the ribonucleotide of uracil.

• RNA typically exists as a single strand, whereas DNA exists as a double- stranded helical molecule.

. Since the RNA molecule is a single strand complementary to only one of the two strands of a gene, its guanine content does not necessarily equal its cytosine content, nor does its adenine content necessarily equal its uracil content.

However, given the proper complementary base sequence with opposite polarity, the single strand of RNA is capable of folding back on itself like a hairpin and thus acquiring double-stranded characteristics: G pairing with C, and A pairing with U.

The RNA transcript with a 5' to 3' is complementary to the template strand with its 3' to 5' polarity.

Note that: the sequence in the RNA transcript is the same as that in the coding strand, except that

the U of the transcript replaces the T of the gene

the initiating nucleotide of RNAs contain a triphosphate (ie, pppA-above). terminal 5-