Presentation onDNA and RNA Structure

Prepared by:-TAZEEN ANWAAR

UZMA IMTIYAZ

INDEXIntroduction to DNADNA structureIntroduction to RNARNA StructureDifference in DNA and RNA

DNA is a polymer made of nucleotides. DNA is found in chromosomes , mitochondria

and chloroplast. DNA carries genetic information.

What is DNA?

James Watson and Francis Crick worked out the three-dimensional structure of DNA, based on work by Rosalind Franklin

Figure 10.3A, B

Components of DNADNA is polymer of nucleotides where each

nucleotide comprises of the following:Sugar moleculePhosphate Nitrogeneous bases which are pyrimidines

and purines.

Each nucleotide is joined to one another in a chain by covalent bond between the sugar of one nucleotide and the phosphate of the next resulting in an alternating sugar phosphate backbone.

Hydrogen bonds bind the nitrogeneous bases of two separate polynucleotide strands to make duble stranded DNA.

Two strands of DNA run in opposite direction thus are anti parallel.

Two biopolymer strands are coiled around each other to form a double helix.

RNARNA is a polymer of ribonucleotides linked

together by 3’ to 5’ phosphodiester linkage.

Types of RNA molecules:

In all prokaryotic and eukaryotic organisms three main classes of RNA molecules exist

1. Messenger RNA (m RNA)2. Transfer RNA (t RNA)3. Ribosomal RNA(r RNA)

Structurally ,DNA and RNA are nearly identical .However there are three fundametal differences that account for the very different functions of two molecules.

1. RNA has a ribose sugar molecule while DNA has a deoxyribose sugar.

2. RNA nucleotides have URACIL base instead of THYMINE present in DNA.

3. RNA is a single strand structure while DNA is a double strand structure.

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