Nucleotides
- Created by: LauraNannini
- Created on: 19-04-20 07:50
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- Topic 4
- Nucleic acids
- Nucleotides are small molecules that join together to make DNA or RNA
- DNA
- Store all genetic information in a small volume
- Small variation in structure that act as a simple code
- Stable and information is not easily corruptible
- Reproduces information of themselves
- Double helix
- RNA
- can be in the the forms off
- mRNA- encodes amino acids sequence
- tRNA- Brings amino acids to the ribosome
- rRNA- makes up the ribosome
- single strand
- can be in the the forms off
- DNA structure
- DNA nucleotides pentose sugar is deoxyribose
- They have four bases A, T, C and G
- A- Adenine: pairs with T
- T- Thymine: pairs with A
- C- Cytosine: pairs with G
- G- Guanine: pairs with C
- The attraction between the bases in a double helix structure are hydrogen bonds
- Structure of a DNA nucleotide
- Nucleotide monomers combine through condensation reactions which form Phosphodiester bonds
- Each nucleotide is attached to a polynucleotide strand
- A polynucleotide strand
- Two polynucleotide strands
- They run in antiparallel directions
- Each nucleotide is attached to a polynucleotide strand
- Watson and Crick discovered the DNA structure
- RNA structure
- Pentose sugar is ribose
- The thymine base is replaced by Uracil 'U'
- single stranded and joined together by phosphodiester bonds
- DNA replication
- 3 Possible ways of DNA replication
- Conservative
- Semi-conservative
- 1. the DNA unwinds and hydrogen bonds are broken by DNA helicase
- 2. strands are kept separate by SSB proteins but the polynucleotide strand stays in tact
- 3. DNA polymerase attaches new nucleotides to each other through condensation reaction
- new strand is built on each of the original so there is now an exact copy as the original
- One starnd from the original strand is kept and is attached to the newly copied complimentary strand
- Dispersive
- 3 Possible ways of DNA replication
- Evidence for semi-conservative replication
- Meselon and Stahl experiment
- Grew bacteria in heavy nitrogen (N15) as they replicated the bacterial DNA became N15
- The N15 bacteria was then put in N14 and extracted DNA from the bacteria and centrifuged it in caesium chloride
- The different DNA extracts then float in the mixture at different levels depending on its size (bigger ones at the bottoms)
- ATP
- Bodies immediate source of energy for every process
- Has a ribose sugar with an adenine base and THREE phosphate groups
- Energy is released when a phosphate group is released
- ATP hydrolayse catalyzes the hydrolisis reaction
- The products made is adenine diphosphate, Phosphorus and water.
- The extra phosphate group released can be recycled by the body for other uses
- ATP hydrolayse catalyzes the hydrolisis reaction
- Nucleic acids
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