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33 Cards in this Set
- Front
- Back
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How does hydrogen bonding occur?
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• polar molecule
• delta negative oxygen • delta positive hydrogen x2 A zig zag line from hydrogen and oxygen of another molecule = hydrogen bonding |
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How do hydrogen bonds give water a high specific heat capacity?
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• hydrogen bonds between water molecules can absorb a lot of energy
• therefore it takes a lot of energy to heat water up • useful for living organisms as it stops rapid temperature changes and allowing them to keep their temperature fairly stable |
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How do hydrogen bonds give water a high latent heat of evaporation?
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• takes a lot of energy to break hydrogen bonds
• therefore water has a high latent heat of evaporation as a lot of energy is used up when water evaporates • this is useful for living organisms because it means waters great for cooling things |
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How does waters polarity make it cohesive?
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• water molecules are polar so that means they are attracted between molecules of same type
• this helps water to flow making it great for transporting substances |
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How does waters polarity make it a good solvent?
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• substances needed to be transported are ionic
• as waters polar the ends are attached to the positive/ negative in ion • they surround ions and they'll dissolve • so it's a good solvent for other polar molecules |
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What is the structure of an amino acid?
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R (variable group)
H2N - C - COOH H Amino. Carboxylic Group Group |
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What is the bond called that joins amino acids together?
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Peptide bond
Condensation reaction - wAter is released H2N - CRH - C double bond O - N hydrogen - CRH- COOH |
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What is a proteins primary structure?
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The sequence of amino acids in a polypeptide chain
• held together by peptide bonds between amino acids |
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What is the proteins second structure?
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• polypeptide chain doesn't remain flat
• hydrogen bonds form between the amino acids • causes a coil into alpha helix Or beta pleated sheet |
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What is the tertiary structure.. Excluding all the bonds?
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• coiled or folded chain of amino acids is coiled and folded even more
• for proteins made from a single polypeptide chain the tertiary structure froms their 3D final structure |
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How are the hydrophilic and hydrophilic interactions affecting the tertiary structure?
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• Hydrophobic and hydrophilic interactions
- hydrophobic groups close together in protein they clump together - means hydrophilic groups are more likely to be pushed to the outside - affecting how the protein folds up in finals structure |
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How does disulphides bonds affect the tertiary structure?
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• 2 molecules of amino acid CYSTEINE come close together
• the sulfur atom in one cysteine bonds to the sulfur in other cysteine and forms a disulphide bond |
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How do ionic interactions affect the tertiary structure?
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These are weak attractions between negative and positive charges on different parts of the molecules
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What is the quaternary structure with reference to the structure of haemoglobin?
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• proteins made of several different polypeptide chains held together by bonds
- quaternary structure is the way the polypeptide chains are assembled together • haemoglobin is made of 4 polypeptide chains bonded together. Determines the final 3D shape |
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What is the structure of collagen?
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• three polypeptide chains that are tightly coiled into a strong triple helix
• chains are interlinked by strong covalent bonds • form fibres |
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Compare the structure and function of haemoglobin as a globular protein and collagen as a fibrous protein
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• Collagen is a fibrous protein that forms supportive tissue in animals and haemoglobin is a globular protein with a haem group that binds to oxygen, carrying it around body
- collagen is insoluble and haemoglobin is soluble - globular protein roll up to form balls and fibrous proteins form fibres |
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What is the molecular structure of alpha glucose?
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ABBA
• six Carbons |
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How is maltose made?
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• disaccharide
• therefore 2 alpha glucose molecules are jointed by a GLYCOSIDIC BOND - h2O is removed |
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How is amylose made?
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• polysaccharide
• formed by 2 monosaccharides • LOTS OF ALPHA GLUCOSE MOLECULES JOINED TOGETHER BY GLYCOSIDIC BONDS TO FORM AMYLOSE |
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Compare the structure and fiction of starch (amylose) and cellulose?
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• amylose is unbranched alpha glucose
- helix and it makes it compact and really good for storage cause you can fit more in to a small space • cellulose is unbranched beta glucose - bonds between sugars are straight - linked by hydrogen bonds to form microfibrils |
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What is the structure of glycogen?
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• Highly branched
- side branches means enzymes can break down molecule to get at the glycosidic bonds easily and realise glucose - compact and good for storage |
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How are the structures of glucose, amylose, glycogen and cellulose related to their functions?
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• starch is the main energy storage in plants - breaks down into glucose
- amylose is unbranched and can compact - amylopectin branched can allow glucose to be realised • cellulose is the major component of cell walls in plants - hydrogen bonds • glucose can be broken down into water and co2 in respiration to release energy • glycogen is branched so can be broken down into glucose |
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What's the difference between a triglyceride and a phospholipid?
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Triglyceride =
- 3 fatty acid tails - glycerol -ester bond Phospholipids = • 2 fatty acid tails • glycerol • phosphate groups • Ester bond |
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What is the structure of cholesterol?
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• hydrocarbon ring structure attached to a hydrocarbon tail
• hydrocarbon ring has a polar hydroxyl group which makes cholesterol slightly soluble • however insoluble in blood so is carried around the body by proteins called lipoproteins |
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How is the structure of triglyceride related to it's function?
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• mainly used as energy storage molecules
- hydrocarbon tails contain a lot of chemical energy therefore it is released when they are broken down - they're insoluble so they don't cause water to enter the cells by osmosis |
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How is the structure of phospholipids related to it's function?
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• they make up the Bilayer of cells and control what enters and leaves a cell
• hydrophobic tail hydrophilic head forms a double layer • the centre is hydrophobic so water soluble substances cat easily pass through it - acts as a barrier |
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How is cholesterol a structure related to it's function?
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• helps strengthen the cell membrane by interacting with the bilayer
• small size and flattened shapes allows cholesterol to fit in between the phospholipid molecules - they bind to tails and causes ten to pack more closely |
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How to carry out the biuret test to test for proteins?
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1) test solution needs to be alkaline so you add a few drops of SODIUM HYDROXIDE
2) Then add some COPPER (II) SULFATE SOLUTION • if protein is present a 💜🔮👾🎵 purple 💜🎵👾🍠🍆🍠🍆 layer forms • if no protein is present the solution stays 🐟🐋🐳 🌍🌍blue 🌍🌎🏊🐟🐬🐋🐳 |
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How to carry out the Benedictus test for reducing sugars?
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REDUCING SUGARS (glucose)
• add Benedictus reagent to a sample and place in a water bath of 80' • if it's positive it will form a coloured precipitate of brick red • high conc of reducing sugar the deeper the colour - a more accurate way of doing this is to filter the solution and weigh precipitate to compare |
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How to carry out a Benedict's test for non reducing sugars?
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• to test sucrose you have to break them down to monosaccharides
• boil with HCL and then neutralise it with sodium hydrogencarbonate • repeat Benedict's test • brick red on the second test |
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How to carry out the emulsion test?
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• shake with ethanol for a minute
• the pour the solution into water • lipid present solution turn milky • no lipid stays clear |
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How to carry out the iodine test for starch?
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• adds iodine dissolved in potassium iodide solution to test sample
• starch present it turns blue black • if not it stays browny - orange |
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Describe how the concentration of glucose in a solution may be determined using colorimetry
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Measures the absorbency of light by the solution
• the high conc. the colours he high the absorbance The higher the glucose concentration the lower the absorbance • results used to make a calibration cure |
