Nucleic Acids
- Created by: Cnicholls25
- Created on: 19-01-19 14:36
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- Nucleic Acids
- Nucleotides
- consists of a pentose sugar, phosphate group and organic bases
- a condensation reaction joins two nucleotides
- forms a dinucleotide
- bond formed between the pentose sugar and phosphate group
- phosphodiester bond
- joining of multiple nucleotides by condensation reaction
- forms polynucleotide
- ester bond between pentose sugar and phosphate
- glyosidic bond between bases and pentose sugar
- DNA
- made of deoxyribose sugar, phosphate group and 4 different organic bases
- double helix structure
- stability
- phosphodiester backbone protects the reactive organic bases
- higher the proportion of C - G the more stable
- four different bases are adenine, thymine, guanine and adenine
- A always pairs with T
- 2 hydrogen bond
- G always pairs with C
- 3 hydrogen bonds
- A and G are purines (two carbon nitrogen rings)
- T and C are pyrimidines (single carbon nitrogen ring)
- A always pairs with T
- adaptations to carry out function
- DNA is stable
- rarely mutates
- two separate strands only joined by hydrogen bonds
- which allows them to be separated during replication
- large molecule
- can carry large amounts of genetic infromation
- bases protected by the backbone
- genetic info is protected from being corrupted
- DNA is stable
- Semi Conservative Replication
- Requirements
- 4 nucleotides with 4 bases A G C T
- both strands of DNA to act as a template
- source of chemical energy
- enzyme DNA polymerase
- Process
- 1.) enzyme DNA helicase breaks hydrogen bonds between bases causing DNA strands to separate
- 2.) each exposed polynucleotide acts a template where free activated nucleotides bind to their complementary bases
- 3.) nucleotides join in condensation reaction by the enzyme DNA polymerase to form a new polynucleotide strand
- 4.) any remaining nucleotides continue to pair
- 2 identical DNA molecules are formed with 1 original strand and 1 new. 50% of DNA is saved
- Requirements
- RNA
- single short chain
- made up of a ribose sugar phosphate group and organic base
- has the bases adenine guanine cytosine and uracil
- RNA types
- mRNA
- transfers genetic info
- rRNA
- tRNA
- used in protein synthesis
- mRNA
- Nucleotides
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