3.5.1 Structure of DNA and RNA

DNA

Deoxyribonucleic acid

Holds genetic material

Polymers of nucleotides

RNA

Ribonucleic acid

Transfers genetic material from DNA to ribosomes

Polymers of nucleotides

Where are ribosomes formed from

RNA and proteins

Nucleotides structure

Pentose sugar

Base

Phosphate group

DNA nucleotide structure

Deoxyribose sugar

Hydrogen (H) at 2’

Phosphate

bases: adenine, thymine, cytosine, guanine

RNA nucleotide structure

Ribose sugar

Hydroxyl(OH) at 2’

Phosphate group

Bases: Adenine,Uracil, Cytosine, Guanine

Phosphodiester bond

Formed by a condensation reaction of two nucleotides between phosphate group and pentose sugar

DNA molecule

Double helix with two polynucleotide chains arranged in antiparallel held together by hydrogen bonds between specific complementary bases

RNA molecule

One polynucleotide strand -single stranded

Chains relatively short compared to DNA

Simplicity of DNA

Scientist doubted that DNA molecule could carry the genetic code

This is due to the relatively simple chemical composition of DNA (only made up of simple repeating units)