nucleic acids
- Created by: samsam001
- Created on: 21-03-14 20:15
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- Nucleic acids
- DNA is deoxyribonucleic acid
- Its a double stranded molecule made of two nucleotides
- A DNA nucleotide is made up of a phosphate group, a five carbon sugar called deoxyribsoe and a base.
- DNA has 4 bases Adenine, guanine,cytosine and thymine
- A and G are purine bases
- C and T are pyramid bases
- DNA has 4 bases Adenine, guanine,cytosine and thymine
- The nucleotides are linked strongly by covalent bonds between the phosphate and deoxyribose group.
- The phosphate groups bond to the carbon 5 and 3 of the deoxyribose ring
- the two strands are linked to each other by weak hydrogen bonds between the bases.
- A is always with T and are linked by two hydrogen bonds
- C and G are linked by 3 hydrogen bonds
- The two strands of DNA run in opposite directions, this is called anti-parralel and they twist to form a double helix
- The DNA moleculesin a cell nucleus are replicate before division.
- 1. the two strands unzip and untwist
- 2. complimentary free bases then link up to the exposed bases on the strands.
- 3.they are then linked together by the formation of bonds between their deoxyribose and phosphate groups.this is catalysed by DNA polymerase
- 4.two new molecules are formed each containing an old and new strand, the process is semi-conservative
- 3.they are then linked together by the formation of bonds between their deoxyribose and phosphate groups.this is catalysed by DNA polymerase
- 2. complimentary free bases then link up to the exposed bases on the strands.
- 1. the two strands unzip and untwist
- The sequence off bases in a DNA molecules codes for the sequence of amino acids in a protein to be made on the ribosome's
- 3 bases code for one amino acid
- a sequence of DNA nucleotides that codes for one popypeptide is known as a gene
- 3 bases code for one amino acid
- RNA is ribonucleicacid, instead of thymine they contain uracil
- during protein synthesis,an RNA molecule is built up against one of the DNA strands in a gene.
- The RNA then travels out of the nucleus to a ribosome, where its sequence of bases is used to determine the sequence of amino acids in the polypeptide
- DNA is deoxyribonucleic acid
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