2. 1 BIOLOGY PRESENTATIONS FOR A-LEVEL, IN MULTIMEDIA JAMES BOWLES, 2001 BIOLOGY PRESENTATIONS FOR A-LEVEL, IN MULTIMEDIA JAMES BOWLES, 2001 LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END

3. 2 ‘A’ Level Biology Nucleic Acids

4. 3 Nucleotides A nucleotide contains:O Phosphate Group Pentose Sugar Base

5. 4 Nucleotides The phosphate group gives the nucleotide an acidic nature O O O-O- O-O- P

6. 5 The pentose sugar may be either Ribose (RNA) or Deoxyribose (DNA)OO OHHHHRiboseDeoxyribose

7. 6 There are five bases Pyramidines Purines AdenineGuanine CytosineThymineUracil

8. 7 Polynucleotides Bonds can form between carbon 3 of the pentose sugar and the phosphate group on carbon 5 of an adjacent nucleotide O O

9. 8 Long chains can be built up in this way - Polynucleotides O O O O O O O

10. 9 The ends of these chains are named on the basis of which carbon is not involved in bonding O O O O O O O 5’ 3’

11. 10 Deoxyribonucleic Acid O HHSugar is Deoxyribose Bases are: Adenine Guanine Cytosine Thymine DNA

12. 11 DNA Two chains of polynucleotide run anti-parallel to one another O O O O O O O O O O O O O O

13. 12 DNA The chains are arranged as a DOUBLE HELIX with 10 bases to each complete turn

14. 13 DNA Base pairing is complimentary Adenine Thymine The bonds are hydrogen bonds Guanine Cytosine

15. 14 Ribonucleic AcidO OHH Sugar is Ribose Bases are: Adenine Guanine Cytosine Uracil RNA

16. 15 Messenger RNA

17. 16 mRNA Single-stranded, uncoiled polynucleotide Messenger RNA UAAGCGUAUUGGCAUGUAAGCGUAUUGGCAUGUAAGCGUAUUGGCAUGUAAGCGUAUUGGCAUG

18. 17 mRNA mRNA is a copy of the DNA code which is exported from the nucleus Messenger RNA UAAGCGUAUUGGCAUGUAAGCGUAUUGGCAUGUAAGCGUAUUGGCAUGUAAGCGUAUUGGCAUG

19. 18 tRNA Single-stranded RNA arranged in a ‘clover leaf’ shape Transfer RNA

20. 19 tRNA tRNA attaches to amino acids in the cytoplasm Transfer RNA Amino Acid binding site

21. 20 tRNA The anticodon lines up alongside the appropriate codon on mRNA during protein synthesis Transfer RNA Anticodon

22. 21 rRNA This is a long length of RNA produced in the nucleolus Ribosomal RNA

23. 22 rRNA It has areas of single and double helices Ribosomal RNA

24. 23 rRNA In the cytoplasm it combines with proteins to form ribosomes Ribosomal RNA

25. 24 DNA vs. RNA DNARNA

26. 25 DNA vs. RNA DNARNA Always a double helix May have single or double helix

27. 26 DNA vs. RNA DNARNA Always a double helix May have single or double helix Sugar is deoxyribose Sugar is ribose

28. 27 DNA vs. RNA Bases are A, T, G & C DNARNA Always a double helix May have single or double helix Sugar is deoxyribose Sugar is ribose Bases are A, U, G & C

29. 28 DNA vs. RNA May be temporary DNARNA Always a double helix May have single or double helix Sugar is deoxyribose Bases are A, T, G & C Sugar is ribose Bases are A, U, G & C Permanent

30. 29 DNA vs. RNA Chemically very stable Chemically less stable DNARNA Always a double helix May have single or double helix Sugar is deoxyribose Bases are A, T, G & C Sugar is ribose Bases are A, U, G & C May be temporary Permanent

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