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Nucleic Acid The structure of DNA and RNA. 5C sugar The structure of a nucleotide P Organic base DNA and RNA are polymers of nucleotides.

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Presentation on theme: "Nucleic Acid The structure of DNA and RNA. 5C sugar The structure of a nucleotide P Organic base DNA and RNA are polymers of nucleotides."— Presentation transcript:

1 Nucleic Acid The structure of DNA and RNA

2 5C sugar The structure of a nucleotide P Organic base DNA and RNA are polymers of nucleotides

3 There are two types of bases Purines are double ring structures Adenine andGuanineare both purines The bases in nucleotides can differ A or G Purines and pyrimidines

4 Pyrimidines are single ring structures CTU Cytosine, thymine and uracil are pyrimidines More simply shown

5 ACT G Nucleotides join together to form a polymer The bases stick out to the side The nucleotides can be in any order The phosphate group of one nucleotide joins to the pentose sugar of the next

6 The structure of DNA DNA is made up of four types of DNA nucleotides DNA nucleotides contain deoxyribose sugar The DNA nucleotides contain the bases adenine thymine cytosine guanine C G TA DNA has two chains of nucleotides

7 The two chains are joined by the bases The base pairing is specific and complementary Adenine always joins with thymine Guanine always joins with cytosine Purines always join with pyrimidines This makes the molecule the same width along its length Bases are joined by H bonds

8 If two pyrimidines pair the molecule would be thinner The two backbone strands of sugar phosphate are the same distance apart If two purines pair the molecule would be thicker

9 Complementary base pairing A T GC A G TC The bases are joined by hydrogen bonds

10 2 H bonds between adenine and thymine A T G C 3 H bonds between guanine and cytosine To pair one of the nucleotides must flip over

11 TA A C G T G A C T G C The two strands run anti-parallel

12 The two strands are twisted into a double helix The helical shape and the H bonds help to keep DNA stable Subject to copyright clearance a suitable image showing a double helix could be inserted here. e.g. one similar to that found at:

13 Sugar–phosphate backbone The two strands are joined by the bases The double helix Subject to copyright clearance a suitable image showing a double helix could be inserted here. e.g. one similar to that found at:

14 The structure of RNA Messenger RNA Transfer RNA Ribosomal RNA

15 Structure of RNA RNA nucleotides contain the bases adenine uracil cytosine guanine C G UA The thymine in DNA is replaced by uracil in RNA form single strand polymers Contain ribose sugar

16 Messenger RNA (mRNA) is made in the nucleus from RNA nucleotides is involved in protein synthesis is relatively short lived

17 Transfer RNA (tRNA) Is a single strand folded into a cloverleaf shape Has a specific site to which specific amino acids can attach There is a different type of tRNA for each type of amino acid Each type of tRNA has three bases which are specific to the type of amino acid which will attach These three bases are called the anticodon

18 GCA tRNASpecific amino acid attaches Anticodon – specific to the amino acid which attaches to this tRNA molecule More simply drawn

19 Draw up a table of differences between DNA and RNA Click here to go to AS Guru and build a molecule of DNA Activities End


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