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Biological molecules…read more

Slide 2

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These are all representations of water molecules.
The two hydrogen atoms and the one oxygen
atom are joined to each other through covalent
In these bonds, the negative electrons aren't
shared equally, and the atom with the greater
share of negative electrons will be slightly ()
negative, which makes the other atom involved in
the bond slightly () positive.
Molecules that have these uneven charges are
called polar, meaning they have regions of
negativity and regions
*When of positivity.
atoms share electrons in order to fill their outermost shell…read more

Slide 3

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Hydrogen bonds
The positive and negative regions of water molecules attract other water
molecules forming bonds. These bonds are called hydrogen bonds.
Hydrogen bonds are strong enough to raise the
boiling and melting point of water. The strong
attractions raise these points because more
energy is needed to overcome the attraction.
They're also weak enough to keep reforming as
the water molecules move around.…read more

Slide 4

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Roles of water
Water acts as a solvent. A solvent is a substance that other substances are
able to dissolve in. Water makes a good solvent because its molecules are
Due to their polarity water molecules are able to dissolve ions and polar
Water is unable to dissolve non-polar
molecules because they don't have regions of
charge, which means there will be no
attraction between the non-polar molecules
and the water molecules.…read more

Slide 5

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Roles of water...
Water also acts as a medium for chemical reactions. The cytosol (cytoplasm)
of prokaryotic and eukaryotic cells is mostly water.
Water is useful for transporting dissolved material in and out of cells, and
around the body (eg. It's a transport medium for gametes)…read more

Slide 6

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Latent heat of evaporation/vaporisation
Water has a high latent heat of evaporation. This means that a lot of energy
is needed for water to change state (for it to evaporate or vaporise).
This is useful for evaporative cooling, which allows organisms to cool down.
Eg:…read more

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noreen zahra


please refer the word site for the notes 

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