AS Biology DNA and RNA

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  • these are the monomers of DNA and RNA and when put together in large quantities will form polymers dna and rna they are bonded with phospodiester bonds to form the backbone of the molecule
  • they are made up of a phosphate group, a  pentose sugar ( ribose in RNA and deoxyriobose for DNA) as well as a base
  • there are four bases in DNA and they are cytosine, guanine , adonine and thymine( Caburys Goodies Are Tasty) they pair C and G and T and A
  • however in Rna you don't have thymine and this is replaced with U Uracil
  • they both have a phosphate sugar back bone
  • the bonds between the bases are hydrogen bonds and there are 3 between C and G and 2 between A and T 
  • DNA is anti parallel this means that one strand of it is the right way up but the other side of it it is upside down to the other one 

the bases come in two sizes 

  • pyrimines - singlular ring structure examples inculde cytosine and thymine and urecil
  • purine - is a double ring structure examples inculde guanine and adenine

a small one pair with a big one to maintain an even structure throughout the molecule

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DNA and Rna

DNA codes for amino acids which will form proteins to build you . it takes 3 bases to code for an amino acid  of which there are 20 this is called the tripet code but is also referred to at this level as a condon . Dna has a phosphate sugar backbone and is in the form of a double helix 

Dna will not leave the nucleus , so there must be a messenger molecule to take it to be reproduced this is messanger Rna ( mRNA) RNA is a single stand of an acid and is copy of the DNA in as far as the RNA has the opposite bases as the DNA which as been copied so when they make a copy of the RNA ( which must have the right base pairs)you get a copy of the DNA ( does that make sense ... )

The mRNA will go out of the Neucleus and go into the cystoplasm and into the Ribosomes where it will be used to make proteins after it has been translated

rRNA is ribosomal RNA and is made in the nucleous of a cell and is used to make ribsomes when paired with Amino acids

tRNA is transfer RNA and is used transfer amino acids to a growing chain of polypeptides ( aka a protein)

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great resource!

Chloe Thorn

glad it helped :)

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