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Biochemical molecules

Biochemical molecules. An introduction. How does this fit into the scheme?. F212 – June paper Module 1 (of 3) – Biological molecules 2.1.1 Biological molecules 2.1.2 DNA 2.1.3 Enzymes. We will actually teach this in the order; molecules, enzymes then DNA

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Biochemical molecules

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  1. Biochemical molecules An introduction

  2. How does this fit into the scheme? • F212 – June paper • Module 1 (of 3) – Biological molecules • 2.1.1 Biological molecules • 2.1.2 DNA • 2.1.3 Enzymes We will actually teach this in the order; molecules, enzymes then DNA You will see that in your exam question booklet they are in this order

  3. Time to start thinking……. • What are you made of ? • (sugar and spice is not an acceptable answer)

  4. Four types to look at • Water • Carbohydrates • Lipids • Proteins Revise anything you know about all of these from GCSE!

  5. Elements involved • The big three – C, H and O • Others that turn up frequently – N, P and S • There are small amounts of others too e.g. minerals – Ca, K, Na, Cl, Mg • Can you name any instances we have met already where these elements are involved?

  6. Colouring in!! Bush Right to left • O – red • C – black • H – white • N – blue • P - purple Rabbit Right to left • O – red • C – black • H – white • N – blue • Ca – silver • P - purple Why does the bunny have so much more calcium than the Plant that there is enough to make a stripe on the diagram?

  7. Take one 156lb human 100lbs oxygen 28lbs carbon 15lbs hydrogen 4.6lb nitrogen 2.3lb calcium 1.6lb phosphorous 8.5oz potassium 6oz sulphur 3.7oz sodium 3.7oz chlorine 1.25oz magnesium 0.15oz iron 1.9g zinc 0.2g copper 0.02g manganese 0.015g molybdenum some cobalt some selenium and traces of others Worth about 5 shillings Components of a human (1968)

  8. Carbon based life • Where is carbon on the periodic table? • How many electrons does it have in its outer shell? • How many covalent bonds can it form? • Being able to form 4 covalent bonds carbon can be the basis of complex molecules – long chains, rings and these can include single, double or triple bonds. This molecular complexity is vital to life. Turning the deceased into diamonds

  9. Hydrogen atom

  10. Water It’s kinda weird – but very useful Intro to water and its properties

  11. The weirdness of water H2O, CH4, NH3 • All small, covalently bonded molecules but methane and ammonia are gases – water is a liquid! .

  12. Hydrogen bonding in water Explanatory animation • The polar nature of the covalent bonds that hold water together, and the hydrogen bonds between the water molecules, explain the properties of water – that make it so useful to life. John Kyrk water – extension only

  13. Water – a polar molecule

  14. Hydrogen bonding

  15. Properties of water • Liquid at biological temperatures – high latent heat • Good solvent • Good thermal buffer - high specific heat capacity • High surface tension • Most dense at 4°C – ice floats • These properties can all be explained due to the polar nature of water and the H bonds • Also, in reactions it can be used e.g. as a source of hydrogen Entire website about water

  16. Liquid at room temperatures • Organisms can interact with it, live in and on it, use it as a solvent etc. which they couldn’t if it were a gas. • As a liquid it is incompressible • Therefore it can be used for support – e.g. turgor pressure in plants

  17. High Latent Heat • It takes a lot of energy to change the physical state of water, therefore it is unlikely to change, so it is a stable environment for organisms to live in – it is less likely to evaporate or freeze than other liquids • This also means that the evaporation of water can be used as an effective cooling mechanism e.g. panting and sweating

  18. Good solvent Explanatory animation • As a solvent of polar molecules water can dissolve most biological molecules – except lipids • Therefore reactions can easily take place within water • Organisms can therefore use water as the basis of their cytoplasm • In multicellular organisms it can also be used as a transport medium e.g. it is the basis of plasma and sap

  19. High specific heat capacity • It takes a lot of energy to change the temperature of water • Therefore it is a stable environment to live in • Also internal body temperatures are less likely to change

  20. High surface tension • Allows organisms to live on the surface of water e.g. pond skaters • Is also important in capillary action e.g. in the xylem (cohesion)

  21. Most dense at 4°C • Ice (solid water) floats on liquid water • This insulates the lower levels of a pond so the entire pond doesn’t freeze • It provides a habitat for penguins. • It sets up currents in the water which, particularly in the sea, circulates nutrients

  22. Reactant • Is used in hydrolysis reactions to split macromolecules into smaller units by adding water. • And the reverse - joining monomers to form polymers by the removal of water – condensation polymerisation. • Is a source of hydrogen for the reactions of photosynthesis.

  23. Has it stuck? • P147 Question no. 4 (just write down the missing words) • Answers page 252 Quiz on properties of water

  24. Homework • Revise all GCSE knowledge of carbohydrates, proteins and lipids, including the biochemical tests for sugars, starchs, proteins and lipids

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