1. 8.1Nucleotides Starter What is DNA ? Where will you find DNA in a cell? Draw the basic structure of a pentose sugar

2. 8.1Nucleotides Aims: What are the components of DNA? How are these components arranged within the DNA double helix? What is the function of DNA?

3. Nucleotide structure (monomer) What type of reaction is involved when the phosphate group and base are joined to the sugar? What type of bonds are formed? Phosphate group Organic nitrogenous base Pentose sugar

4. DNA (and RNA) is a nucleic acid It is made from lots of nucleotide monomers joined together by condensation reactions to form a poly nucleotide

5. DNA - deoxyribonucleic acid The pentose sugar in DNA is deoxyribose RNA - ribonucleic acid The pentose sugar in RNA is ribose Spot the difference

6. Double ring Adenine & Guanine Single ring Cytosine & Thymine Nitrogenous bases

8. Polynucleotide

9. Draw the structure of a nucleotide Which nitrogenous bases will you find in DNA? Which of these are purines? pyrimidines?

10. Nucleotide structure (monomer) Phosphate group Organic nitrogenous base Pentose sugar

11. DNA is usually double stranded There are two antiparallel DNA strands held together by hydrogen bonding between complementary bases The two strands are twisted into a double helix

13. Label the nitrogenous bases & show the hydrogen bonds between complementary base pairs cytosine thymine adenine guanine

14. What is the relationship between the quantities adenine and thymine in DNA? What is the relationship between the quantities of guanine and cytosine in DNA? What about the ratio in different species? 10 bases for each complete turn (3.4nm)

15. Understanding checkpoint! Using the sweets can you explain: What are the components of DNA? How are these components arranged within the DNA double helix?

16. What do you think is the function of DNA? How is the DNA adapted for its function? 10 bases for each complete turn (3.4nm)

17. Plenary Construct a table to show the function and adaptations of DNA. FunctionAdaptation Passing on genetic materialVery stable and therefore can pass from generation to generation without change

18. Plenary Construct a table to show the function and adaptations of DNA. FunctionAdaptation Passing on genetic materialVery stable and therefore can pass from generation to generation without change 2 separate strands only joined by H bonds allows them to be separated easily during DNA replication Large number of bases (3.2 billion for variation) Large molecule can carry lots of genetic information Depends on sequence of basesBy having base pairs within the helix protects them from being corrupted

19. 8.1Nucleotides Aims: What are the components of DNA? How are these components arranged within the DNA double helix? What is the function of DNA?

20. 2.1 – 16DNA Starter What do you know about the structure of DNA?

21. Teaching objectives The structure of DNA Replication of DNA Learning outcomes Draw an outline structure of DNA Describe the semi-conservative replication of DNA

22. Before a cell divides the DNA must be replicated. This happens during interphase of the cell cycle

23. DNA replication Controlled by a group of enzymes called DNA polymerase The double helix unwinds Hydrogen bonds between the complementary bases are broken to ‘unzip’ the DNA Free nucleotides (from the nucleoplasm) pair up with complementary bases and hydrogen bonds form between them Condensation reactions occur between the phosphate & pentose sugar of neighbouring nucleotides to form the sugar phosphate backbone

25. The process of DNA replication occurs all the way along the DNA strand resulting in an exact replica of the DNA molecule. DNA replication is described as ‘semi conservative’ because each of the resulting DNA molecules has one strand of the original DNA and 1 newly synthesised strand

26. Plenary A DNA molecule is 23% guanine. What percentage of each of the other bases would it contain? G = 23% C = 23% C + G = 46% So A + T = 54% (to make a total of 100%) A = 27% T = 27%

27. 2.1 – 17The roles of DNA & RNA Starter What is the function of DNA?

28. Teaching objectives The structure of RNA The role of DNA & RNA in the cells of living organisms Learning outcomes State what a gene is Describe the 3 different types of RNA Outline the concept of protein synthesis

29. RNA What type of molecule is RNA? What are the monomers of this molecule? What type of bond joins these monomers together? In what way is the pentose sugar found in RNA, different from the pentose sugar found in DNA? In what way are the bases found in RNA different to the bases found in DNA?

30. Describe the structure of mRNA There are 3 different types of RNA Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA)

31. Describe the structure of tRNA

32. There are 2 different units of rRNA – a large subunit and a small subunit which, together with proteins form ribosomes

33. A gene is a section of DNA nucleotides that codes for the sequence of amino acids that make up a particular polypeptide.

34. Different genes are switched on and off in different cells. When a gene is activated that section of the DNA is copied into a complementary strand of mRNA The mRNA then leaves the nucleus through a nuclear pore and attaches to a ribosome (made of rRNA and protein).

35. As the mRNA passes through a groove in the ribosome, tRNA brings specific amino acids into position. The sequence of amino acids is joined by peptide bonds to form the primary structure of the polypeptide.

36. Depending on the specific groups in each amino acid the polypeptide chain then forms secondary & tertiary structures

37. Outline the role of DNA and RNA in living cells DNA – genetic code – contains genes with instructions for making specific polypeptides RNA – responsible for reading the instructions on the DNA and translating them into amino acids to form polypeptides