Genetic Code & Cell Function
- Created by: beth-marie2511
- Created on: 17-06-16 13:09
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- Genetic Code & Cell Function
- DNA Structure
- Nucleotide
- Phosphate
- Pentose Sugar
- Nitrogenous base
- Pyrimidine
- Thymine
- Cytosine
- Purine
- Adenine
- Guanine
- Pyrimidine
- Many nucleotides join together to form 2 polynucleotide strands
- They join up between the phosphate of one nucleotide and the sugar of another
- Sugar-phosphate backbone
- Two poly-nucleotide strands are coiled and form a spiral
- Double Helix
- They join up between the phosphate of one nucleotide and the sugar of another
- Complimentary Base Pairing
- Adenine pairs with Thymine
- Guanine pairs with Cytosine
- Nucleotide
- Main Functions of DNA
- Replication in dividing cells
- Carrying information for protein synthesis
- DNA Replication
- 1. DNA helix UNWINDS. Hydrogen bonds holding base pairs together break causing the two halves of the molecule to UNZIP
- DNA Helicase unzips the DNA
- 2. As the strands separate DNA polymerase catalyses the addition of free nucleotides to the exposed bases
- 3. Each strand acts as a TEMPLATE so that free nucleotides can be joined to their complimentary bases
- By DNA polymerase
- 4. 2 DNA molecules form
- Each molecule consists of one NEWLY SYNTH-ESISED strand and one ORIGINAL TEMPLATE strand
- This is semi-conservative replication
- 1. DNA helix UNWINDS. Hydrogen bonds holding base pairs together break causing the two halves of the molecule to UNZIP
- DNA Structure
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