Every cell in body is identically, genetically. When they specialise, some of the genes are switched on, and some switched off. Different genes produce different proteins and enzymes and therefore, different characteristics.
Sequence of bases in protein synthesis of amino acids wihch makes up the proteins.
DNA Strands are held together by H bonds. Double structure: support, protects bases.
Semi conservative replication: New DNA molecules after replication has one strand on old DNA, one new.
What is meant by specific base pairing? When each base only pairs with one other base known as complimentary. E.G. Guanine and Cytosine.
Why is specific base pairing important? It allows identical/exact copies of DNA to be made, both strands act as templates, and complimentary bases pair alongside both strands.
2 Features of DNA that make it stable are: The large number of Hydrogen bonds, there is a strong sugar phosphate backbone, and the coiling and two strands reduce the chance of damage to the bases.
DNA Polymerase joins the bases. Replication takes place in INTERPHASE.
Semiconservative Replication: Both strands acts as template to make two complimentary copies, the daughter DNA is one new strand, (free nucleotides), and one original.
Differences in DNA and RNA: DNA has Deoxyribose, RNA has Ribose. DNA contains the bases T, A, C and G. RNA Contains the bases A, U, G and C.
The DNA strands separate then the hydrogen bonds between them are broken. Each strand forms a template, and a new strand is built alongside it from free nucleotides, depending on the solution it is in. If, for instance, it contained radioactive thymine (the solution), it would be complimentary to the adenine on the the old, non radioactive strand, and would form bonds with it. This means the new strands in the new DNA molecules are radioactive.
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