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BB10A: Cells, Biomolecules & Genetics 2003-04 Semester 1 Tuesday 30 Sept. Lecture 3 Biomolecules & their interactions with Water Andrew Pearson.

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Presentation on theme: "BB10A: Cells, Biomolecules & Genetics 2003-04 Semester 1 Tuesday 30 Sept. Lecture 3 Biomolecules & their interactions with Water Andrew Pearson."— Presentation transcript:

1 BB10A: Cells, Biomolecules & Genetics Semester 1 Tuesday 30 Sept. Lecture 3 Biomolecules & their interactions with Water Andrew Pearson

2 Life on our planet has evolved to cope with a predominantly aqueous environment: roughly 70% of the Earths surface & animal bodies are H 2 O Biomolecules & their interactions with Water

3 The properties of H 2 O have therefore had a powerful effect upon the forces of natural selection at the level of the Biomolecule. Let us look at some properties of H 2 O. Biomolecules & their interactions with Water

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6 In contrast to hydrophobic substances, many biochemically important ions and molecules are so hydrophilic that Osmotic pressure results. Biomolecules & their interactions with Water

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8 Another important property of H 2 O is its ability to dissociate into both a weak acid and a weak base. Biomolecules & their interactions with Water

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11 The effect of water upon natural selection is quite marked even at the molecular level: the case of the most abundant biosynthesised molecule, Glucose. Biomolecules & their interactions with Water

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16 Proteoglycan aggregate Chondroitin sulphateKeratan sulphate Hyaluronic Acid core

17 The less it is allowed to interact with aqueous media, the stronger a H-bond can be. This is important in the stability of macromolecules such as DNA: Biomolecules & their interactions with Water

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19 All things naturally prefer (are more stable in) the lowest possible energy state. For H 2 O in the biosphere (i.e. between 0 o C and 100 o C) this means random motion, not an ordered structure. Biomolecules & their interactions with Water

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23 This effect is important in the stabilisation of biomembranes Biomolecules & their interactions with Water

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27 Relative abundances of elements in the universe Biomolecules & their interactions with Water

28 Relative abundances of elements in Earths crust Biomolecules & their interactions with Water

29 Relative abundances of elements in humans Biomolecules & their interactions with Water

30 Universal Earths crust Human body Biomolecules & their interactions with Water

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32 Apart from photosynthesising organisms, which take energy from e/m radiation, all the biochemical needs of the biosphere for life come from: chemical elements, salts and molecules found in the lower regions of the atmosphere, the hydrosphere and the upper parts of the lithosphere. Biomolecules & their interactions with Water

33 Ecology studies are often enhanced by under- standing how and why elements cycle through different systems in the biosphere, & recent perturbations of ecological balances by human activities have brought these matters into sharp focus. Biomolecules & their interactions with Water

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