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50 Cards in this Set
- Front
- Back
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In polymerisation, polymers are made of
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Small identical molecules (monomers).
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2 monomers link & water is lost
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condensation reaction
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Polymers broken down to monomers by the chemical insertion of water
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hydrolysis
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Carbohydrates contain:
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carbon, hydrogen & oxygen
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Main function of carbohydrates
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storage & release of energy but also compose cellular structures (cell walls of plants)
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3 classes of carbohydrates
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monosaccharides, disaccharides & polysaccharides
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General formula for monosaccharides
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(CH2O)n
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2 forms of glucose
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alpha glucose and beta glucose (isomers)
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Isomers
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molecule with same chemical formula but different arrangement.
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ABBA
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Alpha = OH group Below C1, Beta = OH group Above C1
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Examples of hexose sugars |
glucose, fructose and galactose
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Properties of monosaccharides
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soluble because of small size so easily dissolves in cells and transported in bloodstream.
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Main functions of monosaccharides
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Triose = intermediate molecules in respiration and photosynthesis Pentose= part of nucleotides to build up nucleic acids Hexose = glucose is the main substrate for respiration. |
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Disaccharides
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2 hexose sugars combined in condensation reaction. (C12H22O11 and alpha 1,4 glycosidic bonds)
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Glucose + Glucose = Maltose
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found in seeds & important source of glucose in germination
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Glucose + Fructose = Sucrose
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transported in phloem
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Glucose + Galactose = Lactose
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found in milk and source of energy for young of mammals
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Link between 2 sugars
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Glycosidic Bond
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Smallest polysaccharide is made up of 3 glucose monomers but is usually made up of thousands
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Massive size = Insoluble
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Glucose is soluble in water so will have an osmotic effect in cell so is converted to the polysaccharide ...
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Starch -Large = can’t diffuse easily out of cells -Insoluble = no osmotic effect -Compact structure = energy stored efficiently |
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Examples of polysaccharides
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Starch and glycogen =storage made of alpha glucose -Cellulose and chitin= structural made of beta glucose |
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Starch is made up of 2 different molecules (found in plants)
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Amylose and amylopectin
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Amylose: straight/unbranched chains, helix structure, alpha 1-4 glycosidic bonds
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Amylopectin: 1-4 and 1-6 alpha glycosidic bonds, branched chains
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Glycogen is found in liver and muscle cells and is highly branched so...
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allows quicker release of glucose from ends of branches |
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-Cellulose gives plant cells rigidity because cell wall is inelastic and has a high tensile strength to prevent cell from bursting
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• Glucose monomers form straight chains • Each glucose molecule rotated 180 from previous • Hydrogen bonds form between crosslinks • Thousands of cellulose polysaccharides form microfibrils (hydrogen bonds=stability) • Many microfibrils = cellulose fibres. |
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-Chitin is similar to cellulose -Made of b glucose like monomers linked into long straight chains. -1 OH group replaced with an amino acid -Form microfibril, many microfibril = fibril
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- Collectively forms muco-polysaccharide: - lightweight - waterproof - very strong - Forms exoskeleton of insects, arachnids and crustaceans |
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- Lipids include fatty acids, triglycerides & phospholipids. -Lipids contain same elements as carbohydrates but with less oxygen - Soluble in organic solvents (acetone or ethanol) - Can be classed as oils & fats...
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Fats -Solid @ room temp -saturated -commonly found in animals Oils -Liquid @ room temp -unsaturated -commonly found in plants |
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Triglycerides are made of... (Is not a polysaccharide) |
- 1 glycerol head - 3 fatty acid tails - Ester bonds - OH of glycerol & COOH of fatty acid react and release water (loses 3 H2Os) |
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Glycerol
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- An alcohol - Hydrophilic - dissolves in water - Formula: C3H8O3 |
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Fatty Acids
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- 3 parts: - methyl group (CH3) - hydrocarbon chain (CH2, length changes) - carboxylic group (COOH) - hydrophobic - repels water |
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Saturated fatty acid: - no C to C double bonds - Max. number of H atoms |
Unsaturated Fatty Acids: - 1 or more C to C double bonds - Does not contain max. number of H atoms |
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Low Density Lipoproteins (LAME): - transport saturated fats - fatty materials block major arteries - can cause a heart attack or stroke |
High Density Lipoproteins (HAPPY): - transport unsaturated fats - carry harmful fats away to liver - higher proportion of HDL lowers risk of heart disease |
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Waxes
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- similar to fats & oils but contain alcohol - hydrophobic - important in land organisms: insects & plants = waxy cuticle cuts down water loss
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Functions of lipids
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1. Energy storage molecules: 2x as much energy as carbohydrate/g 2. Protection from physical harm 3. Thermal insulation: Adepose tissue, under skin, prevents loss of heat 4. Metabolic water produced from lipid oxidation 5. Buoyancy: Fat floats 6.Waterproofing |
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Phospholipids
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- 1 phosphate head - 1 glycerol head - both heads are hydrophilic - 2 fatty acids - 2 ester bonds |
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Amino acids contain
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- Carbon - hydrogen - oxygen - nitrogen - sometimes sulphur General formula : R.NH2CH.COOH (R = variable group which result in 20 diff amino acids) - Amino group(NH2) & Carboxyl group (COOH) |
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2 amino acids joined together with peptide bond
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dipeptide
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Many amino acids joined together by peptide bonds
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polypeptide / proteins
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Primary structure
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sequence of amino acids
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Secondary structure |
- coiling of primary structure -alpha helix or beta pleated sheet (or both) - hydrogen bonds - E.G of alpha helices: keratin (hair & nails) and collagen (skin & connected tissues) -fibrous proteins: long, strong & insoluble - E.G of beta pleated sheet: the protein silk |
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Tertiary Structure
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- folding of secondary structure to give complex 3-D globular protein (mostly alpha helix) - spherical & soluble - E.G enzymes, hormones and antibodies -Bonds: -ionic -hydrogen -disulphide - hydrophobic interactions |
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Quaternary structure |
-Protein consists of more than 1 polypeptide chain (haemoglobin) - May contain prosthetic groups - Same bonds as the tertiary structure |
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Properties of proteins |
1. Crystalline 2. Colourless 3. Amphoteric |
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Test for Reducing sugars
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1. Benedict's reagent & sample 2. Boil 3. If positive - blue to brick red |
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Test for non-reducing sugars
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1. Do test for reducing sugar 2. Add acid & heat (hydrolyse glycosidic bond) 3. Then add alkali (neutralise it) 4. Add heat 5. If positive - blue to brick red |
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Test for proteins |
1. Biuret reagent and sample 2. Shake 3. If positive - blue to purple |
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Test for starch
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1. Iodine Potassium-iodide solution & sample 2. If positive - Orange to blue/black
Qualitative |
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Test for lipids
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1. Ethanol & sample 2. Shake 3. Pour into cold water 4. If positive - cloudy white emulsion |
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Water
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- 2 slightly positive hydrogen - slightly negative oxygen -dipole - covalently bonded - weak hydrogen bond between 2 water molecules - weak lattice structure |
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Properties of water
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1. Surface Tension -cohesion produces an uneven distribution of force -Surface of water forms skin which supports aquatic insects 2. Universal solvent - it is polar so attracts other polar molecules and ions 3. Specific Heat Capacity - amount of heat energy required to increase temp of water - Resists temp change = more stable enviro for aquatic organisms 4. Latent Heat Capacity - energy need to change the state - sweating is a significant cooling mechanism 5. Density - Ice floats on water, provides insulating layer for aquatic organisms 6. Transparency - light for photosynthesis in aquatic plants
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