Excess glucose is stored as starch. A mixture of two polysacchrides amolyse and amylopectin
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Amylose
Long unbranched chain of A-glucose. The angles of the glycosidic bonds produce a coiled structure. Good for storage being so compact
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Amylopectin
Long branched chain of a-glucose. Side branches allow enzymes to act on it to break down the molecule so glucose is released quickly.
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Glycogen
Excess glucose is stored as glycogen, polysacchride of alpha glucose, more side branches so more enzymes can act on it, allowing glucose to be released more quickly, good compact for storage.
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Cellulose
Long unbranched chain of beta glucose of beta glucose forming straight line cellulose chains. Linked by hydrogen bonds forming strong fibres known as micro fibrils. Structural support.
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Iodine test for Starch
Add iodine dissolved in potassium iodine solution yo test sample. If present sample will change to black- blue, if not present sample will stay red-orange.
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Lipids
Contain hydrocarbons, not made from polymers like starch and proteins
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Triglycerides
One molecule of glycerol, and three fatty acids . Fatty acids have a hydrophobic tail and hydrophillic head
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Saturated Fatty acids
That is had no double bonds between their carbon atoms
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Unsaturated Fatty acids
That is had a double bond between the carbon atoms
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Formation of triglyceride
They form through condensation reactions releasing water creating an ester bond which occurs three times between the glycerol and three fatty acids
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Phospholipids
One glycerol molecule, 2 fatty acids and one phosphate group. Phosphate group is hydrophillic
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Triglyceride Properties
Good for energy storage as when broken down they release chemical energy. Insoluble so it doesn't affect water potential.
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Phospholipids make up a bilayer
Bilayer is formed in the cell membrane, controlling what enter and what leaves the cell, forms double layer due to tails and heads
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Emulsion Test
Shake the test substance with ethanol for about a minute. Then pour into water where if a lipid is present then a milky emulsion will show.
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Proteins complex
Monomers of proteins are amino acids, two amino acids forms a dipeptide, more than two a polypeptide is formed.
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Dipeptide and polypeptide
Amino acids are linked by condensation reactions, a molecule of water is released.
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Primary Structure
Sequence of amino acids in the polypeptide chain
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Secondary Structure
Polypeptide chain doesn't remain flat, and hydrogen bonds form between amino acids. Making it coil into an alpha helix structure or a beta pleated structure.
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Tertiary Structure
The structure is folded further, more bonds are formed such as hydrogen,ionic and disulfide bridges. Disulfide forms between molecules of cysteine in amino acids. Proteins made from a single polypeptide this is the final stage
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Quaternary Structure
Proteins maybe made from many chains held by bonds.
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Protein Shape and Function
Shape determines its function
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Biuret Test
Test solution needs to be alkaline therefore must add few drops of sodium hydroxide, then add copper sulfate. If the solution turns purple, protein is present.
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Enzymes
Biological catalyst that speeds up a reaction, catalyse metabolic reaction.
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Activation Energy
The energy required for the reaction to start
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Enzyme Substrate lowers activation energy
Two substrate molecules need to be joined, being attached to the enzyme reduces repulsion is reduced making bonds form easier. Then enzymes catalysing a breakdown reaction puts stain of substance
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