Biology 1.1 revision notes

includes all information on water, compounds needed in body and carbohydrates. 

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Biology Revision AS- 1.1
Polar molecule- negative and positive charge
Hydrophobic- repels water
Hydrophilic- attracts water
Water molecules are able to approach one another quite closely. The charges attract strongly. They
are also dipolar which means they have two charges.
Water molecule move slowly, when they are heated up they move faster and some escape. When
they are cooled down they slow and become stable. Water is denser than ice and also creates a nice
lattice. It expands when it freezes and becomes less dense and ice then floats on top of water.
Animals can then live under the ice.
Colour: Transparent (transmission of life)
Light can be let through. Sun is needed for plants to photosynthesis. Feeds every single person in the
world. Sun light can travel through the sea and so underwater plants can still photosynthesis.
Surface Tension
Characteristics (properties of something)
Water molecules are negative and positive charge. In the layer between air and water they become
more attracted to each other than the air. This makes them more stable near the top. Bugs can then
survive on the surface of the water and can have a habitat there. This is due to the way some bugs
are able to spread their weight out.
Specific Heat Capacity
Has one of the highest specific heat capacities- means there is a massive difference between ice and
vapour. A lot of energy therefore is needed to be lost of used. Important because it means people
can live (not frazzle) lakes and rivers need a lot of energy to freeze or boil.
State at Room Temperature
Water is a liquid at room temperature. However, all other similar molecules are gases. Positive
hydrogen is attracted to negative oxygen. Slows the molecules down and so they are liquid at room
Latent Heat (sweating)
Exercise= sweat=gas
This requires a lot of heat from your body which then leaves you cooler (VAPORISATION)
Hydrogen bonding. Attraction of one molecule to
another molecule. It is a strong attraction. Creates
water droplets. Xylem Phloem allows liquids to
move up and down the plant.

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Dr Barnetts first lessons
Elements- substance containing one type of atom- rarely found in living organisms- e.g. mg,fe.
Compounds ­ substances containing two or more different elements bonded together:
Ionic e.g. NaCl
Covalent e.g.…read more


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