2.1 Structure of DNA and RNA
Nucleotide Structure
- Individual nucleotides are made up of…
- @@A pentose sugar@@
- @@A phosphate group@@
- A nitrogen containing organic base (@@Adenine, Cytosine, Thymine, Guanine, Uracil@@)
- DNA has A, @@T@@, C and G
- RNA has A, @@U@@, C, and G
- They are all joined together via a @@condensation reaction@@
- Two mononucleotides may be joined by a @@phosphodiester bond@@ between the sugar of one and the phosphate group of another
RNA Structure
- Relatively @@short@@
- @@Single stranded@@
- @@Ribose@@ sugar
- @@Adenine and Uracil@@ bonded together
- Cytosine and Guanine bonded together
- 3 types, @@tRNA, premRNA, and mRNA@@
DNA Structure
- In 1953, James Watson and Francis Crick worked on the structure of DNA following work by Rosalind Franklin
- Sugar is @@deoxyribose@@
- @@Longer strands@@
- @@Double stranded@@
- Joined by @@hydrogen bonds@@ between different bases
- @@Adenine and Thymine@@
- Cytosine and Guanine
Stability of DNA
- Phosphodiester backbone @@protects the more chemically reactive bases@@ inside double helix
- @@Hydrogen bonds link the organic base pairs@@ forms bridged between the two strands
- @@C--G form 3 hydrogen bonds, so the more C--G pairings in a strand the stronger it is@@
Function of DNA
- Hereditary material responsible for @@passing information down through generations@@
- Stable structure allows to passed won through generations without significant changes, @@most mutations are repaired so persistent mutations are rare@@
- Separate strands only joined by @@hydrogen bonds so can be split easily@@ for replication
- @@Large molecule so can carry lots of info@@
- Base pairs @@protected by backbone@@ to protect info
- @@Base pairs allow DNA to be replicated identically easily@@