.
Edexcel AS Biology
Revision Notes
, Edexcel AS Biology Revision Notes Written by Tim Filtness
A word of caution
These revision notes are designed to help you, NOT do the job of revision
for you. Ultimately, only you can learn this material: you can’t pay, cajole
or persuade anyone to do it for you! Additionally, these notes are the bare
bones (your text book and class notes are almost certainly better sources
of information if you’re aiming for the highest grades). So treat these
notes as a minimalist approach for someone aiming for a solid B grade. At
this point you might want to get your own notes to cross-reference with
the material here. Why not add your own annotations to improve what’s
already here?
Understanding the jargon:
1. The 9 Core Practicals are not discussed here.
Don’t forget to revise them too!
2. All Key Words are given underlined in red, these
are words specifically mentioned on the syllabus!
3. There are many blue “How Science Works” boxes
in the text book. In past years these have almost
always been the basis of a number of exam
questions...
, Edexcel AS Biology Revision Notes Written by Tim Filtness
Edexcel AS Revision
Unit 1: Lifestyle, Transport, Genes
& &
Health
Topic 1: Lifestyle, health & Risk
1.1.2
Water molecules are polar
H = Positively charged (δ+)
O = Negatively charged (δ-)
This allows them to form Hydrogen
Bonds with other water molecules. This
gives water some useful properties;
Property Explanation
Less dense as a solid Arctic ecosystems float, ice insulates water beneath it
etc
High SHC Cells do not heat up or cool down easily, therefore can
hold a fairly stable temp. (cf enzymes)
Present naturally in all Allows the water cycle to function
three states
Transparent Allows photosynthesis underwater
Cohesion Generates surface tension, capillary uptake,
transpiration etc
Good solvent Essential role in transport in biological systems
Immiscible with Allows membranes to form and, therefore, control
hydrophobic molecules movement in / out of cells
High latent heat of Evaporation of water has a strong cooling effect and
evaporation comparatively little water is required to lose a lot of
heat
Buffer Water is capable of accepting and donating protons,
therefore acts as a buffer
, Edexcel AS Biology Revision Notes Written by Tim Filtness
1.1.3
Saccharides are made from sugar molecules, which are made from
combinations of the elements Carbon, Hydrogen and Oxygen only
Saccharides are used for;
1. Fuels for respiration (e.g. glucose)
2. Energy storage molecules (e.g. starch and glycogen)
3. Structural molecules (e.g. cellulose)
Monosaccharides – one sugar molecule only
Disaccharides – two sugar molecules joined together
Oligosaccharides – a few sugar molecules joined together
Polysaccharides – many sugar molecules joined together
Disaccharide Name Component monosaccharides
Maltose Glucose + Glucose
Sucrose Glucose + Fructose
Lactose Glucose + Galactose
You need to know the different structures of glucose. You should
be able to draw this out if requested.
OH
H
α Glucose Β Glucose
Edexcel AS Biology
Revision Notes
, Edexcel AS Biology Revision Notes Written by Tim Filtness
A word of caution
These revision notes are designed to help you, NOT do the job of revision
for you. Ultimately, only you can learn this material: you can’t pay, cajole
or persuade anyone to do it for you! Additionally, these notes are the bare
bones (your text book and class notes are almost certainly better sources
of information if you’re aiming for the highest grades). So treat these
notes as a minimalist approach for someone aiming for a solid B grade. At
this point you might want to get your own notes to cross-reference with
the material here. Why not add your own annotations to improve what’s
already here?
Understanding the jargon:
1. The 9 Core Practicals are not discussed here.
Don’t forget to revise them too!
2. All Key Words are given underlined in red, these
are words specifically mentioned on the syllabus!
3. There are many blue “How Science Works” boxes
in the text book. In past years these have almost
always been the basis of a number of exam
questions...
, Edexcel AS Biology Revision Notes Written by Tim Filtness
Edexcel AS Revision
Unit 1: Lifestyle, Transport, Genes
& &
Health
Topic 1: Lifestyle, health & Risk
1.1.2
Water molecules are polar
H = Positively charged (δ+)
O = Negatively charged (δ-)
This allows them to form Hydrogen
Bonds with other water molecules. This
gives water some useful properties;
Property Explanation
Less dense as a solid Arctic ecosystems float, ice insulates water beneath it
etc
High SHC Cells do not heat up or cool down easily, therefore can
hold a fairly stable temp. (cf enzymes)
Present naturally in all Allows the water cycle to function
three states
Transparent Allows photosynthesis underwater
Cohesion Generates surface tension, capillary uptake,
transpiration etc
Good solvent Essential role in transport in biological systems
Immiscible with Allows membranes to form and, therefore, control
hydrophobic molecules movement in / out of cells
High latent heat of Evaporation of water has a strong cooling effect and
evaporation comparatively little water is required to lose a lot of
heat
Buffer Water is capable of accepting and donating protons,
therefore acts as a buffer
, Edexcel AS Biology Revision Notes Written by Tim Filtness
1.1.3
Saccharides are made from sugar molecules, which are made from
combinations of the elements Carbon, Hydrogen and Oxygen only
Saccharides are used for;
1. Fuels for respiration (e.g. glucose)
2. Energy storage molecules (e.g. starch and glycogen)
3. Structural molecules (e.g. cellulose)
Monosaccharides – one sugar molecule only
Disaccharides – two sugar molecules joined together
Oligosaccharides – a few sugar molecules joined together
Polysaccharides – many sugar molecules joined together
Disaccharide Name Component monosaccharides
Maltose Glucose + Glucose
Sucrose Glucose + Fructose
Lactose Glucose + Galactose
You need to know the different structures of glucose. You should
be able to draw this out if requested.
OH
H
α Glucose Β Glucose
