1. Biology 3.3 Describe the role of DNA in relation to gene expression

2. Cell Types What is the difference between prokaryotes and eukaryotes? Devise a table that highlights the differences in general structure of plant, animal and bacterial cells at the organelle, DNA and chromosome levels. Find the info on page 43 and 44 of the course book.

3. Cell organelles What are the roles of the following organelles? Match up the cell structure and function cards.

4. Karyotypes Chromosomes arranged in groups according to size, shape and banding pattern. Prepared from nuclei of cultured white blood cells ‘frozen’ at metaphase stage of mitosis.

5. Spot the abnormality

6. Chromosomes Explain chromosomes using the following words: (Pg 50 + 59) –DNA –Chromatin –Histone –Centromere –Chromatid

7. Homework Read 42 – 44, highlight, and add to glossary

8. Proteins Proteins are polymers of amino acids A.k.a polypeptides

9. Functions of Proteins Enzymes Structure Carry oxygen Fight disease Cell membrane Chemical messengers

10. Amino Acids Central C atom with 4 groups attached: –Carboxyl group (COOH) –Amine group (NH 2 ) –H atom –Variable ‘R’ group

11. ‘R’ group Can be –Hydrophilic –Hydrophobic –Acidic (containing another COOH group) –Neutral –Basic (containing another NH 2 group) –Sulfur containing (Cysteine and methionine)

12. Peptide Bond Holds Amino Acids together Between COOH of one amino acid and NH 2 of next Condensation reaction – H 2 O produced

13. Protein Structure Complex 3-D shape Denaturation – irreversible, due to extreme heat or pH Globular eg enzymes or Fibrous eg keratin 4 levels to structure

14. Primary Structure Amino Acid sequence determined by genetic code

15. Secondary Structure Folding of polypeptide chain due to H- bonding Alpha-helix – a spiral or coil with ‘R’ groups projecting Beta pleated sheet – flat arrangement

16. Tertiary Structure Secondary structure folded and held by disulfide bridges, hydrophobic or hydrophilic attractions, and weak H-bonds.

17. Quaternary Structure One or more polypeptide chains, and in some cases non-protein components, aggregated together.

18. Protein Structure Animation Lets put the 4 structures together! Watch this animationanimation Now build a protein – (strip of paper) –Sequence along the chain –Fold – helix/pleated sheet –Hydrophilic and hydrophobic folding –More than one polypeptide chain together

19. Homework Read pg 45 + 46, highlight/draw, and add to glossary

20. Enzymes Lower activation energy without being used up in a reaction. Substrate specific animationanimation Named by adding –ase to substrate Co-enzymes complete active site Anabolic – joining molecules (p/s) Catabolic – breaking down molecules (dig/resp)

21. Lowering activation energy

22. Enzyme action Lock and key model animationanimation Induced fit Inhibitors compete for active site

23. Enzymes and membranes Metabolic pathways involve succession of reactions. Enzymes grouped together and bound to membrane Eg. Mitochondria, chloroplasts, golgi bodies

24. Factors affecting enzymes pH Temperature Substrate and enzyme concentration Co-enzymes and heavy metals

25. Homework Read pg 47 + 48, highlight and add to glossary Work sheet – fill word gaps “Proteins and enzymes”

26. DNA Define the following terms: –Nucleotide (give full name of components) –Complementary bases (full names) –Double helix structure –Nucleic Acid –DNA –RNA

27. Purines and Pyrimidines Purines Double ring A + G Pyrimidines Single ring T, U +C

28. Anti-parallel nature 3’ and 5’ ends The two nucleotide strands run in opposite directions. Top strand 5’ to 3’ an bottom strand 3’ to 5’.

29. Introns and Exons Introns – a segment of DNA strand not coding for an amino acid sequence; –it is excised during the RNA processing stage of protein synthesis. Exons – a segment of DNA coding for an amino acid.

30. Discovery The discovery of introns led to the Nobel Prize in Physiology or Medicine in 1993 for Phillip Allen Sharp and Richard J. Roberts. The term intron was introduced by American biochemist Walter Gilbert:[7]Nobel Prize in Physiology or MedicinePhillip Allen SharpRichard J. RobertsbiochemistWalter Gilbert[7] "The notion of the cistron [...] must be replaced by that of a transcription unit containing regions which will be lost from the mature messenger - which I suggest we call introns (for intragenic regions) - alternating with regions which will be expressed - exons." (Gilbert 1978)

31. Functions of DNA and RNA DNA Passing on genetic information The chemical that genes are made out of RNA Protein synthesis Exists as tRNA or mRNA

32. DNA replication Unwinding the molecule Breaking the bonds between the strands Replication (base pair matching) Repackaging Semi-conservative construction Animations + Biozone pageAnimations

33. Okazaki fragments Short pieces of newly replicated DNA along the lagging strand that are later rejoined by DNA ligase. replication animation

34. Key Enzymes RNA and DNA polymerases DNA ligase DNA helicase Write a statement to summarise the function of each enzyme using text pg 52 and photocopy of biozone page

35. Cell division