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Module 1
Water
Specific Heat Capacity: The energy needed to raise the temperature of 1 gram of a
substance by 1°C.
Cohesion: Attraction between molecules of the same type.
Water is Vital to living organisms:
Makes up about 80% of cells content.
Reactant in chemical reactions (photosynthesis, hydrolysis)
Solvent, useful for chemical reactions.
Transports substances
Controls temperature, carries heat when it evaporates.
Water molecules have a simple structure:
One atom of oxygen joined to 2 hydrogen atoms.…read more

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Proteins
Proteins are made from long chains of amino acids:
Dipeptide bond formed when 2 amino acids join together
Polypeptide is formed when more than two amino acids join together
Difference amino acids have different variable groups:
All Amino acids have the same general structure. But a different variable
group (R)
A Carboxyl group (-COOH) and an amino group (-NH2) attached to a
carbon atom.
Amino Acids are joined together by peptide bonds forming Dipeptide and Polypeptides. Water
molecule is released.…read more

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Module 1
o Hydrogen Bonds.
Quaternary Structure: Determined by the tertiary structure of individual polypeptide chains
bonded together, influenced by all.
Protein Shape relates to its function:
Fibrous Proteins are strong and rope shaped and usually found in connective tissue and is
sometimes soluble.
Globular Proteins are round and compact. They are soluble, so they are easy to transport.…read more

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Carbohydrates
Carbohydrates are made from Monosaccharides:
Glucose is a monosaccharide with
six carbon atoms in each
molecule.
Glucose has 2 forms, Alpha ()
and Beta ()
Glucose's structure is related to its function as it's the main energy source in humans/animals. It is
soluble and its bonds contain a lot of energy.…read more

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Cellulose ­ Major Component of cell walls in plants ():
Long, unbranched chains of beta-glucose
Bonds between sugars are straight, cellulose chains straight.
Chains interlinked by hydrogen bonds to form strong fibres called micro fibrils.
The strong fibres mean cellulose provides structural support for cells (e.g.…read more

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Lipids
Triglycerides are a kind of lipid:
Made from one molecule of glycerol with three fatty acids
attached.
Fatty acid molecules have long tails of
hydrocarbons (carbon chains with hydrogen atoms
branching off)
Tails are hydrophobic, making them insoluble in
water.
Fatty acids consist of the same base structure,
but their tails are variable (R).
Phospholipids are similar to triglycerides:
One fatty acid molecule is replaced by a phosphate group
Phosphate group is ionised (charged) making it attract water
molecules.…read more

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They bind to the hydrophobic tails of the phospholipids, causing them to pack closely
together. This helps make the membrane less fluid and more rigid.…read more

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Module 1
How Science Works:
Biochemical Tests for Molecules
Use Benedict's Tests for sugars:
Sugar: General term for Monosaccharides ad disaccharides. All sugars can be classified as
reducing for non-reducing.
Reducing Sugars: Includes all monosaccharides (e.g. glucose) and some disaccharides (e.g.
maltose)
Add blue Benedict's reagent to sample and heat it, making sure it doesn't boil.
If test is positive = colour precipitate forms. (precipitate colour changes from)
Blue-Green-Yellow-Orange-Brick Red
Higher concentration of sugar=further colour change.
Used to compare sugar in different solutions.…read more

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Colorimetry is used to determine concentration of a Glucose Solution:
It is a quantitative version of the Benedict's test which allows you to estimate how much
reducing sugar (e.g. glucose) there is in the solution
Uses Colorimetry ­ Measures strength of a coloured
solution by how much light passes through.
It measures the absorbance of light by the solution.
More Concentration = Higher Absorbance.
It is difficult to measure concentration of the coloured
precipitate. So concentration of blue Benedict's
Solution is measured.…read more

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