Biomacromolecules 2

1. Biomacromolecules 2

2. Nucleic acids • RNA and DNA. What’s the D and the R??? • Deoxyribonucleic acid • Ribonucleic acid

3. The sugars

4. The nucleotide monomer Nitrogen base Phosphate group Negative charge O C 5’ C4’ C1’ C2’ C3’ HO H

5. OH -O P O O Phosphate Group What’sthis? Hydroxyl group! C 5’

6. OH OH How will they bond? O O -O -O P P Nitrogen base Nitrogen base O O O O 5’ 5’ 4’ 4’ 1’ 1’ 3’ 3’ 2’ 2’ H H HO HO

7. OH O -O P Nitrogen base O O 5’ 4’ 1’ 3’ 2’ OH O -O P Nitrogen base O O 5’ 4’ 1’ 3’ 2’ OH HO What type of reaction is this? Phosphodiester bond. One ester bond was there already. A new one has formed between the phosphate on the 5’ end and the oxygen on the 3’end. Condensation polymerisation! O H OH

8. Nucleotides can only be added to the 3’ end of the newly forming strand. • This results in elongation of the new strand in a 5'-3' direction.

9. S sugar P Phosphate group B Nitrogen base The molecule grows from the 5’ end to the 3’ end

10. Base Pairing • There are 4 different bases in DNA . • Adenine • Thymine • Guanine • Cytosine • A always pairs with T and C with G • A &T and C & G are complementary bases • A & G are Pyrimidines • C & T are Purines

11. Two hydrogen bonds form between A and T • Three hydrogen bonds form between C and G • DNA forms a double helix • IN RNA, T is replaced by Uracil

12. DNA is an information molecule • Information is carried in the order of the bases in DNA • The information tells the cell which proteins to make • The information is carried outside the nucleus by mRNA and proteins are built using tRNA and rRNA • RNA is not a double helix

13. Lipids • Fats, oils, waxes, steroids • Functions • Energy storage • Structural components of membranes • Transmission of chemical signals within and between cells • Lipids are not polymers

14. Triglycerides • Triglycerides have a three (tri) fatty acid chains attached to a glycerol • These are the fats used as energy stores Only 3 OH groups so only 3 fatty acid chains. Not polymers

15. Fat or oil? • Fats are solid at room temperature • Oils are liquid • This is determined by the structure of the fatty acid chains • Saturated fatty acids have no double bonds in the fatty acid chain (the chains are saturated with hydrogen atoms) • Unsaturated have some double bonds • Unsaturated have some kinks in the fatty acids chains

16. Saturated Unsaturated Cannot pack as tightly and so is liquid at higher temperatures

17. I water Phospholipids • Phosphate is added to the glycerol instead of another fatty acid chain • Phosphate group is polar, making it hydrophilic • Fatty acid chains are non-polar and therefore hydrophobic I h8 water!

18. Lets form a bilayer. It’s the only way to keep both of us happy. • Phospholipids will naturally form a bilayer in water • The hydrophilic ends will point towards the water • The hydrophobic ends will point to each other

19. Glycolipids • A carbohydrate group is added to the glycerol instead of a third fatty acid chain • Project from plasma membranes and act as signal receptors

20. Steroids are lipids • Cholesterol is a steroid • It is an important structural component of many membranes • It is the starting point for the synthesis of all steroid hormones e.g. oestrogen and testosterone

22. Group work • Groups of 2 • Each group do a different biomacromolecule • Heading will be your biomacromolecule • Content will be subunits, examples, function where they’re found • Any other pertinent information • Include diagrams

23. Macromolecule Building blocks Examples Glycogen, starch monosaccharides Carbohydrates Haemoglobin, Amino acids Proteins nucleotides Nucleic Acids Lipids Fatty acids and glycerol