Term
|
Definition
| the sharing of electrons between atoms to fill the outershellsnof the atoms |
|
|
Term
| what is the strength of a covalent bond? |
|
Definition
|
|
Term
| define a condensation reaction |
|
Definition
| a reaction that occurs when two molecules are joined together with the removal of water |
|
|
Term
| give an example of a condensation reacion |
|
Definition
|
|
Term
| define a hydrolysis reaction |
|
Definition
a reaction that occurs when a molecule is split into two smaller molecules with the addiction of water |
|
|
Term
|
Definition
| a small molecules which binds to many other identical molecules to form a polymer |
|
|
Term
|
Definition
| a large molecules made from many smaller molecules called monomers |
|
|
Term
| in terms of structure, what is water? |
|
Definition
| 2 hydrogen bonds covalently bonded to an oxygen atom |
|
|
Term
|
Definition
| when a charge is not evely distributed across the particle |
|
|
Term
|
Definition
| because the oxygen is more elctronegative than the hydrogen, so it has stronger attraction for the shared pair of electrons, making the oxygen delta negative and the hydrogen delta positive |
|
|
Term
|
Definition
| a weak interaction that can occur wherever molecules contain a slightly negative charged atom bonded to a slightly positive charged hydrogen atom |
|
|
Term
| draw the hydrogen bonds in water |
|
Definition
|
|
Term
| name 7 properties of water |
|
Definition
| 1. high specific heat capacity 2. high latent heat of vaporisation 3. very cohesive 4. good solvent 5. less dense as a solid 6. doesn't dissolve oil 7. a liquid |
|
|
Term
| define specific heat capacity |
|
Definition
| the energy needed to raise the temperature of 1 gram of a substance by 1 degree celsius |
|
|
Term
| why does water have a high specific heat capacity? |
|
Definition
| because of its hydrogen bonds - they water molecules together tightly = lots of energy is required to increase the K.E enough to break the bonds and increase temperature |
|
|
Term
| why is it important that water doesn't experience rapid temperature change? |
|
Definition
| 1. living things need stable temperatures for enzyme reactions 2. aquatic organisms need a stable habitat |
|
|
Term
| define latent heat of vaporisation |
|
Definition
| the energy needed to change the substance from a liquid at its boiling point into a vapour |
|
|
Term
| why does water have a high latent heat of vaporisation? |
|
Definition
| hydrogen bonds - takes a lot of heat to break them, so a lot of energy is used up when water vaporises/evaporates |
|
|
Term
| why is it important that water has a high latent heat of vaporisation? |
|
Definition
| It is useful for cooling us down - mammals sweat, plants transpire |
|
|
Term
|
Definition
| the attraction between molecules of the same type |
|
|
Term
| why are water molecules really cohesive? |
|
Definition
| because they are polar - addition of hydrogen bonds makes them chain like |
|
|
Term
| why is it important that water is cohesive? |
|
Definition
| Helps water to flow = allows transport of water up xylem, allows blood to flow through capillaries |
|
|
Term
| what is water a good solvent for? |
|
Definition
| ionic solutes, such as salt and glucose |
|
|
Term
| why is water a good solvent? |
|
Definition
|
|
Term
| explain how water dissolves a salt, say NaCl |
|
Definition
| the delta positive end (H+) is attracted to the negative Cl- ion. the delta negative end (O-) is attracted to the positive Na+ ion. the ions get completely surrounded by water molecules = dissolves |
|
|
Term
| why is is important that water is a good solvent? |
|
Definition
| it means that ions and minerals can dissolve in water for fish & plants in lakes, and into the blood |
|
|
Term
| why is water less dense as a solid (ice)? |
|
Definition
| there are 4 hydrogen bonds to each water molecule = holds water molecules further apart = lattice = less dense |
|
|
Term
| why is it important that water is less dense as a solid? |
|
Definition
| it means that ice floats = insulating layer over the water |
|
|
Term
| why does water not dissolve oil? |
|
Definition
| because water is polar and oil is not = they have no attraction = oil sits on top |
|
|
Term
|
Definition
| because as water moves it constantly makes and breaks hydrogen bonds |
|
|
Term
| why is it important that water is a liquid at room temperature? |
|
Definition
| 1. provides habitats 2. forms a major component of tissue 3. provides a reaction medium 4. provides a transport medium |
|
|
Term
| what elements make up carbohydrates? |
|
Definition
|
|
Term
| what is the monomer of a carbohydrate? |
|
Definition
|
|
Term
| what is the polymer of a carbohydrate? |
|
Definition
|
|
Term
| what 3 things do carbohydrates act as? |
|
Definition
| 1. source of energy (e.g. glucose) 2. store of energy (e.g. starch and glycogen) 3. structural units (e.g. cellulose in plants & chitin in insects and fungi) |
|
|
Term
| carbohydrates also make up parts of other molecules, such as... |
|
Definition
| nucleic acids & glycolipids |
|
|
Term
|
Definition
| the monomers which make up carbohydrates |
|
|
Term
| what role do monosaccharides play? |
|
Definition
|
|
Term
| why are monsaccharides suited to the role of being a source of energy? |
|
Definition
| they are suited due to the many carbon-hydrogen bonds |
|
|
Term
| name 4 properties of monosaccharides |
|
Definition
| 1. sugars 2. taste sweet 3. soluble in water 4. insoluble in non-water solvents |
|
|
Term
| what shape can monosaccharides be? |
|
Definition
| straight chains, ring, cyclic |
|
|
Term
| what is the backbone of a monosaccharide? |
|
Definition
| a backbone of single bonded carbon atoms |
|
|
Term
| describe a hexose monosaccharide sugar |
|
Definition
| 6 carbons, in solution they are a ring or cyclic, e.g. glucose |
|
|
Term
| describe a pentose monosaccharide sugar |
|
Definition
| 5 carbons, in solution they are ring or cyclic, e.g. ribose |
|
|
Term
| describe a triose monsaccharide sugar |
|
Definition
| 3 carbons, in solution they are straight chains |
|
|
Term
| glucose is a hexose sugar but it exists in many different..... |
|
Definition
|
|
Term
|
Definition
| molecules with the same molecules formula, but the atoms are arranged differently |
|
|
Term
|
Definition
| alpha glucose & beta glucose |
|
|
Term
|
Definition
| 1. alpha glucose 2. beta glucose 3. ribose 4. deoxyribose |
|
|
Term
| what is the molecular formula of alpha glucose? |
|
Definition
|
|
Term
| draw the structural formula of alpha glucose |
|
Definition
|
|
Term
| name 2 functions of alpha glucose |
|
Definition
| 1. energy source 2. component of starch and glycogen |
|
|
Term
| what is the molecular formula of beta glucose? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| what are the functions of beta glucose? |
|
Definition
| 1. energy source 2. component of cellulose - provides structural support |
|
|
Term
| what is the structural difference between alpha glucose and beta glucose? |
|
Definition
| the -OH on carbon 1 is switched |
|
|
Term
| why is it important that the -OH group is switched for the beta glucose? |
|
Definition
| it means that it can bond together in a condensation to form cellulose |
|
|
Term
| what type of sugar is ribose? |
|
Definition
|
|
Term
| what is the molecular formula of ribose? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| what is the role of ribose? |
|
Definition
| it is a component of RNA, ATP and NAD |
|
|
Term
| what type of sugar is deoxyribose? |
|
Definition
|
|
Term
| what is the molecular formula of deoxyribose? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| name 2 properties of disaccharides |
|
Definition
|
|
Term
|
Definition
| maltose, sucrose, lactose |
|
|
Term
| which 2 disaccharides are reducing sugars? |
|
Definition
|
|
Term
| what is a reducing sugar? |
|
Definition
| a sugar with a free reducing centre |
|
|
Term
| are all monsaccharides reducing sugars? |
|
Definition
|
|
Term
| when can carbohydrates not act as reducing sugars? |
|
Definition
| when they are involved in glycosidic bonds, like sucrose |
|
|
Term
| how are disaccharides made? |
|
Definition
| when 2 monosaccharides join together |
|
|
Term
| alpha glucose + alpha glucose = |
|
Definition
|
|
Term
| alpha glucose + fructose = |
|
Definition
|
|
Term
| beta galactose + alpha glucose = |
|
Definition
|
|
Term
| beta glucose + beta glucose = |
|
Definition
|
|
Term
| what reaction do monosaccharides combine by to form disaccharides? |
|
Definition
|
|
Term
| what bond is formed between disaccharides? |
|
Definition
|
|
Term
| explain how 2 monosaccharides react to form a disaccharide, with the example of alpha glucose + alpha glucose |
|
Definition
| 1. the 2 hydroxyl groups line up next to each other 2. a water molecule is removed 3. a glycosidic bond forms between the C1 of the first alpha glucose and the C4 of the second alpha glucose molecule |
|
|
Term
| how is a disaccharide converted back to 2 monosaccharide? |
|
Definition
| add water to provide the -H and -OH = a hydrolysis reaction = breaks glycosidic bond |
|
|
Term
| what are polysaccharides? |
|
Definition
| polymers of monsaccharides |
|
|
Term
| define a homopolysaccharide. give an example |
|
Definition
| a polysaccharide made only of one kind of monosaccharide - starch |
|
|
Term
| define a hertopolysaccharide. give an example |
|
Definition
| a polysaccharide made up of more than one type of monosacharide - hyaluronic acid |
|
|
Term
| glucose is a source of... |
|
Definition
|
|
Term
| what do you form if you join lots of glucose (a monosaccharide)? |
|
Definition
| a polysaccharide which is a store of energy |
|
|
Term
| what do plants store energy as and where? |
|
Definition
|
|
Term
| what do animals store energy as and where? |
|
Definition
| glycogen - liver and muscles |
|
|
Term
| how many types of starch are there? |
|
Definition
|
|
Term
| what are the names of the 2 types of starch? |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| what sort of bond does amylose have? |
|
Definition
|
|
Term
| what chains does amylose have? |
|
Definition
|
|
Term
|
Definition
| it coils into a spiral which is held together by hydrogen bonds |
|
|
Term
| what 2 things makes amylose insoluble? |
|
Definition
| 1. the hydroxyl group on the C2 is insidew the coil 2. the fact that it can form a double helix = presents a hydrophobic external surface with solution |
|
|
Term
| why is it important that amylose coils? |
|
Definition
| makes it compact = uses little space |
|
|
Term
| why is it important the amylose holds glucose in chains? |
|
Definition
| it means the chains can easily be snipped off by hydrolysis when energy is needed for respiration |
|
|
Term
| what is amylopectin made of? |
|
Definition
|
|
Term
| where is amylopectin found? |
|
Definition
|
|
Term
| what bond exists between glucose in amylopectin? |
|
Definition
| 1-4 & 1-6 glycosidic bond |
|
|
Term
| what type of branches does amylopectin have? |
|
Definition
|
|
Term
| what causes the branched chains in amylopectin? |
|
Definition
|
|
Term
| what shape is amylopectin? |
|
Definition
| it coils into a spiral - held together by hydrogen bonds |
|
|
Term
| what makes the amylopectin really compact? |
|
Definition
|
|
Term
| as well as making amylopectin compact, what is the other advantage of branched chains? |
|
Definition
| it allows lots of chance for lots of glucose molecules to be snipped off by hydrolysis at the same time by enzymes |
|
|
Term
| which enzyme is responsible for hydrolysing the 1-4 glycosidic bond in amylopectin? |
|
Definition
|
|
Term
| which enzyme is reponsible for hydrolysing the 1-6 glycosidic bond in amylopectin? |
|
Definition
|
|
Term
| what is the job of glycogen? |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| what bonds exist between glucose monosaccharides to make glycogen? |
|
Definition
| 1-4 and 1-6 glycosidic bonds |
|
|
Term
| what type of chains does glycogen have? |
|
Definition
| branched chains - caused by 1-6 glycosidic bonds |
|
|
Term
| why does glycogen not coil as much as amylopectin? |
|
Definition
| the 1-4 glycosidic bond is smaller |
|
|
Term
| why is glycogen more compact than amylopectin? |
|
Definition
|
|
Term
| why is it important that glucose polysaccharides do not dissolve in cytoplasm? |
|
Definition
| because if they did the water potential would reduce = excess water enter down a water potential gradient = disruption/bursting in animal cells |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| where is cellulose found? |
|
Definition
|
|
Term
| what is the function of the polysaccharide, cellulose? |
|
Definition
| acts as a structural unit in cell walls |
|
|
Term
| what type of polysaccharide is cellulose? |
|
Definition
|
|
Term
| name 3 physical properties of cellulose? |
|
Definition
| tough, insoluble, fibrous |
|
|
Term
| explain how cellulose is formed |
|
Definition
| 1. to bond beta glucose together you have to flip one upside down, otherwise you can't form a glycosidic bond 2. this is a condensation reaction |
|
|
Term
| what are cellulose chains like? |
|
Definition
| straight & lie side by side |
|
|
Term
| why are cellulose chains straight & lie side by side? |
|
Definition
| 1. the -H and -OH groups on C1 are inverted on beta glucose = chain is rotated by 180 degrees = prevent spiraling 2. there are hydrogen bonds between the rotated beta glucose molecules in each chain 3. there are hydrogen bonds between the rotated beta glucose molecules in each chain |
|
|
Term
| when 60-70 cellulose chains are bound together, what do they form? |
|
Definition
|
|
Term
| what is the diameter of a microfibril? |
|
Definition
|
|
Term
| what do microfibrils bundle to form? |
|
Definition
|
|
Term
| what are macrofibrils embedded in? what does this form? |
|
Definition
| pectins - forms plant cell walls |
|
|
Term
| name 6 structures and functions of plant cell walls |
|
Definition
| 1. microfibrils and macrofibrils have high tensile strength = prevents cell from bursting when turgid 2. macrofibrils criss-cross = extra strength 3. difficult to digest 4. plants have no skeleton = cell wall is vital for support 5. space between macrofibrils for water and mineral ions to pass in and out = cell is permeable 6. macrofibril structure can be reinforced with other substances (e.g. cutin & suberin = waterproofing, lignin = waterproofing in xylem vessels) |
|
|
Term
| name 4 human products made of cellulose |
|
Definition
| cotton, photographic film, paper, rayon |
|
|
Term
| besides cellulose, name 2 other structural polysaccharides |
|
Definition
| 1. bacteria cell walls 2. exoskeletons |
|
|
Term
| what are bacterial cell walls made of? |
|
Definition
|
|
Term
| what are exoskeletons made of? |
|
Definition
|
|
Term
| what does chitin on C2 instead of the -OH group on cellulose? |
|
Definition
| an acetylamino group (NH.OCCH3) |
|
|
Term
|
Definition
|
|
Term
|
Definition
| a very large, organic molecule |
|
|
Term
|
Definition
| a group of substances that are soluble in alcohol rather than water |
|
|
Term
|
Definition
| triglyceride, phospholipid, glycolipid, cholesterol, steroids |
|
|
Term
| name 2 types of triglyceride |
|
Definition
|
|
Term
|
Definition
| unsaturated, saturated, polysaturated |
|
|
Term
| what do lipids contain a large amount of? |
|
Definition
|
|
Term
| why are lipids insoluble in water? |
|
Definition
|
|
Term
| what do lipids dissolve in? |
|
Definition
|
|
Term
| what are triglycerides made of? |
|
Definition
| 3 fatty acid chains and 1 glycerol |
|
|
Term
| draw the condensation reaction which makes a triglyceride |
|
Definition
|
|
Term
| what type of bond forms between the fatty acids and the glycerol? |
|
Definition
|
|
Term
| explain the condensation reaction between fatty acids and the glycerol |
|
Definition
| the -COOH group of the fatty acids and the -OH groups of the glycerol line up = condensation reaction = ester bond |
|
|
Term
|
Definition
| a carboxyl group (-COOH) attached to a hydrocarbon chain (2-20 carbons long) |
|
|
Term
| why is a fatty acid and acid? |
|
Definition
| because the -COOH can ionise into H+ and COOH- groups = produces free H+ ions |
|
|
Term
| what type of carbon bonds does a saturated fatty acid have? |
|
Definition
|
|
Term
| what does the lack of double carbon bonds mean in terms of strength between the hydrocarbon chain tails? |
|
Definition
| they strengthen the forces of attraction between the chains as there are no kinks (they are straight) |
|
|
Term
| what state are saturated fatty acids? |
|
Definition
|
|
Term
| what type of carbon bonds does an unsaturated fatty acid have? |
|
Definition
|
|
Term
| what is a fatty acid with one double C bond called? |
|
Definition
|
|
Term
| what is a fatty acid with more than one double C bond called? |
|
Definition
|
|
Term
| what does the double carbon bonds mean in terms of strength between the hydrocarbon chain tails? |
|
Definition
| they weaken the forces of attraction between the chains as they cause kinks = push chains apart slightly |
|
|
Term
| what state are unsaturated fatty acids at room temperature? |
|
Definition
|
|
Term
| name 5 functions of triglycerides |
|
Definition
| 1. energy source 2. energy store 3. insulation 4. buoyancy 5. protection |
|
|
Term
| explain triglycerides as an energy source |
|
Definition
| the ester bonds get broken down in a hydrolysis reaction in respiration = releases energy & generates ATP |
|
|
Term
| why is triglyceride a good energy store |
|
Definition
| it is insoluble in water = can be stored without affecting water potential |
|
|
Term
| where are lipids stored in wales? what does this provide? |
|
Definition
| adipose tissue = heat insulation |
|
|
Term
| where do lipids insulate in humans? |
|
Definition
| in the nerve cells = electrical insulation |
|
|
Term
| why are triglycerides used for buoyancy in walruses? |
|
Definition
| fat is less dense than water |
|
|
Term
| name 2 ways triglycerides provide protection |
|
Definition
| 1. shock absorber to organs 2. surrounds peptidoglycan cell wall in some bacteria |
|
|
Term
| what are phospholipids made up of? |
|
Definition
| 2 fatty acids, 1 phosphate, 1 glycerol |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| why are phospholipids attracted to water? |
|
Definition
| because they have a hydrophilic phosphate head |
|
|
Term
| why are phospholipids described as amphipathic? |
|
Definition
| because they have a hydrophobic tail but a hydrophilic head |
|
|
Term
| what 2 things can happen when phospholipids are put in water? |
|
Definition
| 1. form a layer on top (heads in water & tails sticking out) 2. form a micelle |
|
|
Term
| what type of membrane do phospholipids form? |
|
Definition
|
|
Term
| the phospholipid bilayer is known as selectively permeable. what does this mean? |
|
Definition
| only small and non-polar molecules can pass through = controls ins and outs |
|
|
Term
| what keeps the phospholipid bilayer stable? |
|
Definition
| the fact that the individual phospholipids are allowed to more around in their layer but will not move into any position when their tails are exposed to water |
|
|
Term
| what type of alcohol is the lipid cholesterol? |
|
Definition
|
|
Term
| what is cholesterol made of? |
|
Definition
| 4 carbon-based rings/isoprene units |
|
|
Term
| cholesterol is hydrophobic, so where does it sit in the phospholipid bilayer? |
|
Definition
|
|
Term
| what is the job of cholesterol? |
|
Definition
| regulates fluidity of membrane |
|
|
Term
| where is cholesterol made? |
|
Definition
|
|
Term
| what is the plant version of cholesterol called? |
|
Definition
|
|
Term
| why is stigmasterol different to cholesterol? |
|
Definition
| it has a double bond between C22 & C23 |
|
|
Term
| cholesterol makes testosterone, oestrogen and vitamin D. what are these? |
|
Definition
|
|
Term
|
Definition
| a large polymer made of long chains of amino acids |
|
|
Term
|
Definition
| monomers of all proteins and all amino acids that have the same basic structre |
|
|
Term
| state 3 properties of proteins and state the functions this gives them |
|
Definition
| 1. adopt specific shapes = enzymes, antibodies 2. Form structural components = make up muscles 3.found in membranes = carriers and pores for active transport across the membrane |
|
|
Term
| plants can only make amino acids if they have access to... |
|
Definition
|
|
Term
|
Definition
|
|
Term
| R groups are different for each amino acid. name 4 things R groups can be |
|
Definition
| charged, polar, hydrophobic, hydrophilic |
|
|
Term
| what are amino acids bonded together by? |
|
Definition
|
|
Term
|
Definition
| a covalent bond formed when two amino acids are joined by a condensation reaction |
|
|
Term
| where does the peptide bond form? |
|
Definition
|
|
Term
| amino acid + amino acid = |
|
Definition
|
|
Term
|
Definition
|
|
Term
| what type of enzyme breaks down peptide bonds during digestion in the intestines? |
|
Definition
|
|
Term
| define the primary structure |
|
Definition
| the sequence of amino acids found in a molecule/a protein chain |
|
|
Term
| how many amino acids are there? |
|
Definition
|
|
Term
| what is the function of a protein determined by? |
|
Definition
|
|
Term
| what does the order of amino acids in the primary structure determine in a protein? |
|
Definition
| the shape of the protein molecule through its secondary, tertiary and quaternary structure |
|
|
Term
| why can amino acids be used as buffers? |
|
Definition
| because when dissolved in water, the amino group and carboxyl group can ionise |
|
|
Term
| define secondary structure |
|
Definition
| the coiling or folding of an amino chain, which arises often as a result of hydrogen bond formation between different parts of the chain. |
|
|
Term
| there are 2 types of secondary structure. what are they called? |
|
Definition
| 1. alpha helix 2. beta pleated sheets |
|
|
Term
| in alpha helix, how many amino acids are there per 10 turns of the helix? |
|
Definition
|
|
Term
| how is the alpha helix held together? |
|
Definition
| by hydrogen bonds between the -NH group of one amino acid and the -CO group of another 4 places ahead in the chain |
|
|
Term
| in a beta pleated sheet, the chains fold into what structure? |
|
Definition
|
|
Term
| how s the beta pleated sheet held together? |
|
Definition
| by hydrogen bonds between -NH group of one amino acid and -CO group of another |
|
|
Term
| define tertiary structure |
|
Definition
| the overall 3D shape of a protein molecule |
|
|
Term
| the 3D shape of a molecule arises from... |
|
Definition
| interactions including hydrogen bonds, disulfide bonds, ionic bonds and hydrophobic & hydrophilic interactions |
|
|
Term
| how does tertiary structure occur? |
|
Definition
| when the coils/pleats start to fold |
|
|
Term
| what sort of tertiary shape do fibrous proteins have? |
|
Definition
|
|
Term
| what sort of tertiary shape do globular proteins have? |
|
Definition
|
|
Term
| in globular proteins, where do the amino acids with hydrophobic side chains sit in the tertiary structure? |
|
Definition
|
|
Term
| where are the bonds found in the tertiary structure? |
|
Definition
| 1. ionic = between hydrophobic and hydrophilic bits 2. disulfide = between hydrophobic 3. hydrogen = between all chains |
|
|
Term
| define a quaternary structure |
|
Definition
| a protein structure where a protein consists of more than one polypeptide chain e.g. haemoglobin |
|
|
Term
|
Definition
| primary,secondary and tertiary refers to a single polypeptide chain. quaternary refers to 2 or more polypeptide chains |
|
|
Term
| what bonds hold together primary structure? |
|
Definition
|
|
Term
| what bonds hold together secondary structure? |
|
Definition
|
|
Term
| what bonds hold together tertiary structure? |
|
Definition
| hydrogen, ionic, disulfide, hydrophobic/philic interactions |
|
|
Term
| where do hydrogen bonds form? |
|
Definition
| between hydrogen atoms with a slightly negative charge and other atoms with a slightly positive charge |
|
|
Term
| in what groups to hydrogen bonds form in amino acids? |
|
Definition
| hydroxyl, carboxyl and amino groups e.g. between amino group of one amino acid and carboxyl group of another |
|
|
Term
| what can ionic bonds form between? |
|
Definition
| carboxyl and amino groups that are part of R groups |
|
|
Term
| where can sulphur be found in amino acids? |
|
Definition
| in the R group of the amino acid cysteine - so disulfide bridges form between the R groups of 2 cysteins |
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|
Term
| the 3D tertiary and quaternary structure of proteins are either... |
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Definition
|
|
Term
| give 4 properties of fibrous proteins |
|
Definition
| 1. relatively long and thin 2. regular, repetitive sequences of amino acids 3. insoluble in water 4. metabolically inactive |
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|
Term
| what do the properties of fibrous proteins allow them to have? |
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Definition
| a structural role/function |
|
|
Term
| how many polypeptide chains does collagen have? are they identical |
|
Definition
| 3 identical polypeptide chains |
|
|
Term
| what do the 2 three polypeptide chains of collagen form? |
|
Definition
|
|
Term
| what are collagen polypeptide bonds held together by? |
|
Definition
|
|
Term
| what exists between collagen molecules? |
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Definition
|
|
Term
| what is collagen mainly made of? |
|
Definition
|
|
Term
| what is the function of collagen? |
|
Definition
| to provide mechanical strength |
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|
Term
| name 3 places collagen is found and explain how it provides mechanical strength |
|
Definition
| 1. artery walls = prevents artery wall bursting 2. bones = reinforced with calcium = hard 3. tendons = connect muscles to bones |
|
|
Term
| what type of protein is collagen? |
|
Definition
|
|
Term
| name another fibrous protein |
|
Definition
|
|
Term
|
Definition
| cysteine = lots of disulfide bonds = strong |
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|
Term
|
Definition
| finger nails, hairs, claws, hoofs, horns, scales, fur, feathers |
|
|
Term
| name the 3 functions of keratin |
|
Definition
| 1. mechanical protection 2. impermeable barrier to infection 3. waterproof = stops pollutants entering |
|
|
Term
| name another fibrous protein |
|
Definition
|
|
Term
| what makes elastin strong and stretchy? |
|
Definition
| cross-linking and coiling |
|
|
Term
| name 2 places you can find elastin |
|
Definition
| 1. skin = allows it to stretch and recoil 2. lungs and bladder |
|
|
Term
| name properties of globular proteins |
|
Definition
| 1. relatively spherical shape 2. hydrophobic in R group turn in - soluble in water 3. have metabolic roles 4. very specific shapes |
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Term
|
Definition
|
|
Term
| what is the quaternary structure of haemoglobin made up of? |
|
Definition
| 4 polypeptides - 2 alpha-globin chains and 2 beta-globin chains |
|
|
Term
| what holds haemoglobin together? |
|
Definition
|
|
Term
| what is the formula for oxyhaemoglobin? |
|
Definition
|
|
Term
| haemoglobin contains an iron ion haem group. what is this haem group called? |
|
Definition
|
|
Term
| define a prosthetic group |
|
Definition
| a non-protein component that forms a permanent part of a functioning protein molecule |
|
|
Term
| as well as being a globular protein, what type of protein is haemoglobin? |
|
Definition
| a conjugated protein - contains things other than amino acids, like haem groups |
|
|
Term
| what is the function of haemoglobin? |
|
Definition
| carries oxygen from lungs to body as oxyhaemoglobin |
|
|
Term
| name another globular protein |
|
Definition
|
|
Term
|
Definition
| 2 polypeptide chains - an A chain and a B chain |
|
|
Term
| what holds the tertiary structure of insulin together? |
|
Definition
|
|
Term
| why is insulin soluble in water? |
|
Definition
| because the hydrophilic R groups are on the outside of the molecule |
|
|
Term
|
Definition
| it binds to glycoprotein receptors on the outside of the muscle and fat cells = increases uptake of glucose from blood |
|
|
Term
| name another globular protein |
|
Definition
|
|
Term
|
Definition
| an enzyme that digests protein in the stomach |
|
|
Term
| what is pepsin made up of? |
|
Definition
| a single polypeptide chain of 327 amino acids |
|
|
Term
| what does the dingle polypeptide chain fold into? |
|
Definition
| a symmetrical tertiary structure |
|
|
Term
| how many amino acids does pepsin have? |
|
Definition
|
|
Term
| what holds pepsin together? |
|
Definition
| hydrogen bonds and 2 disulfide bonds |
|
|
Term
| what can computer modelling be used to investigate? |
|
Definition
|
|
Term
| in terms of computer modelling, what was the structure of a secondary structure based on? |
|
Definition
| based upon the probability of an amino acid being in a secondary tertiary structure, derived from already known protein molecular structures |
|
|
Term
| name 2 types of computer modelling |
|
Definition
| 1. Ab initio protein modelling 2. comparative protein modelling |
|
|
Term
| what is Ab initio protein modelling based on? |
|
Definition
| the physical and electrical properties of the atoms in each amino acid in the sequence |
|
|
Term
| name a disadvantage of Ab initio protein modelling |
|
Definition
| it produces many solutions |
|
|
Term
| how comparative protein modelling work? explain |
|
Definition
| it works be protein threading = scans amino acid sequence against a data base of solved structures = produces a set of possible models |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| name the 5 functions of calcium Ca 2+ |
|
Definition
| 1. increases rigidity of bones, teeth,cartilage 2. clots blood 3. activates several enzymes (cofactor)4. stimulates muscle contraction 5. regulates transmission of nerve impulses |
|
|
Term
| mane the 4 functions of sodium Na + |
|
Definition
| 1. regulates osmotic pressure, water levels & pH 2. muscle contraction 3. nervous transmission 4. keeps vacuole turgid |
|
|
Term
| name the 7 functions of potassium K + |
|
Definition
| 1. regulates water levels & pH 2. active transport 3. synthesis of glycogen and protein 4. generates healthy leaves and flowers 5. muscle contraction 6. nervous transmission 7. keeps vacuole turgid |
|
|
Term
| name the 4 functions of hydrogen H + |
|
Definition
| 1. photosynthesis 2. respiration 3. transport of CO2 & O2 in blood 4. regulates blood pH |
|
|
Term
| name the 3 functions of ammonia NH4 + |
|
Definition
| 1. component of amino acids, proteins, vitamins, hormones, chlorophyll, nucleic acids 2. maintains pH 3. nitrogen cycle |
|
|
Term
| name the 3 functions of nitrate NO3 - |
|
Definition
|
|
Term
| name the 2 functions of hydrogencarbonate HCO3 - |
|
Definition
| 1. regulation of blood pH 2. transport of CO2 in & out of blood |
|
|
Term
| name 5 functions of chloride Cl - |
|
Definition
| 1. water balance 2. produces HCl in stomach 3. transports CO2 in & out of blood 4. maintains affinity of haemoglobin to oxygen via allosteric effects 5. regulates blood pH |
|
|
Term
| name 4 functions of phosphate PO4 3- |
|
Definition
| 1. rigidity of bone, teeth, cartilage 2. component of phospholipids, ATP, nucleic acids, some enzymes 3. regulates blood pH 4. helps root growth in plants |
|
|
Term
| name 1 function of hydroxide OH - |
|
Definition
|
|
Term
| explain how one would test for starch |
|
Definition
| 1. add iodine dissolved in potassium iodide solution to the starch sample in a potting tile 2. if starch is present = colour change from yellow-brown to blue-black |
|
|
Term
| explain how one would test for a reducing sugar qualitatively |
|
Definition
| 1. heat & boil with Benedict's solution (alkaline copper(II) sulfate), which is blue, in a water bath 2. if a reducing sugar is present the colour of the solution will change from blue to green to yellow to orange-red 3. the colour change occurs because the copper ions have been reduced from Cu 2+ to Cu + = forms orange-red copper oxide, a precipitate 3. the greater the conc of reducing sugar, the further the colour change goes = therefore we really need to test this quantitatively |
|
|
Term
| explain how one would test for a non-reducing sugar |
|
Definition
| 1. test to check that there are no reducing sugars present 2. take a sample and boil it with dilute hydrochloric acid to hydrolyse the sucrose into glucose and fructose 3. cool solution and add sodium hydrogencarbonate solution to neutralise it 4. do the test for reducing sugars again 5. if a non-reducing sugar is present then it will go from blue to brick red 6. if it stays blue and no precipitate is formed then no sugar is present at all |
|
|
Term
| explain how one can use a glucose strip to test for glucose, instead of doing a reducing sugar test |
|
Definition
| 1. dip strip in a test solution 2. if strip changes colour glucose is present 3. compare colour change to a chart to work out conc of glucose in test solution |
|
|
Term
| what is the name for the test for lipids? explain how one would test for lipids |
|
Definition
| emulsion test 1. mix a sample well with ethanol (because lipids dissolve in alchols but not in water) 2. filter 3. pour solution into a clear test tube 4. a cloudy white emulsion indicates the presence of lipids 5. stays clear = no lipid |
|
|
Term
| what is the name for the test for proteins? explain how one would test for proteins |
|
Definition
| biuret test 1. make the solution alkaline by adding sodium hydroxide solution to the spotting tile 2. add some copper (II) sulfate 3. protein present = turns purple/lilac 4. protein not present = stays blue |
|
|
Term
| what happens to the amount of precipitate formed if more reducing sugar is present when reacted with Benedict's reagent? |
|
Definition
| the amount of precipitate increases |
|
|
Term
| what happens to the amount of copper(II) ions remaining if more reducing sugar is present when reacted with Benedict's reagent? |
|
Definition
| the amount remaining solution decreases |
|
|
Term
| how can we use the amount of precpitate formed and the amount of copper (II) ions remaining to work out conc of sugar in the sample? |
|
Definition
| by using a technique called colorimetry which works by assessing how these 2 variables change |
|
|
Term
|
Definition
| a device that measures the strength of a coloured solution by seeing how much light can pass through it (its absorbency) |
|
|
Term
| the more concentrated the colour of the solution... |
|
Definition
| the higher the absorbency is |
|
|
Term
| explain how we would use a colorimeter to work out the concentration of glucose in a number of solutions |
|
Definition
| 1. filter out the precipitates of all the test tubes & centrifuge to just leave the remaining copper(II) ions because a colorimeter can only work using the same colour 2. solutions with a higher glucose concentration will have a less concentrated solution of copper (II) ions because there will less remaining = less absorbency and more transmittance 3. pour each solution into a cuvette 4. use a red filter to ensure that the colours are definitely all the same 5. put in colorimeter and shine light through to record absorbency |
|
|
Term
| before using a colorimeter what do we do to it? |
|
Definition
| zero it by placing a blank cuvette in it to reset transmission to 100% e.g. water |
|
|
Term
| what do we do with the data from the colorimeter? |
|
Definition
|
|
Term
| explain how one would draw a calibration curve |
|
Definition
| 1. put glucose concentration (g dm -3) on the x axis 2. put transmission (%) on the y axis, or absorbency 3. plot like a normal graph 4. you can use this curve to work out the concentration of an unknown sample |
|
|
Term
| this is a really good video |
|
Definition
| https://www.youtube.com/watch?v=ssgq1QbgJrM |
|
|
Term
|
Definition
| a device that uses a biological molecule, such as an enzyme, to detect a chemical |
|
|
Term
| explain how biosensors work |
|
Definition
| 1. the biological molecule releases a chemical signal 2. the chemical signal is converted to an electrical signal by the TRANSDUCER 3. the electrical signal is processed and measured |
|
|
Term
| give an example of what biosensors can be used for |
|
Definition
| detecting contaminants in water & pathogens in food |
|
|
Term
| what is the aim of chromatography? |
|
Definition
| to separate a mixture into its constituents, in this case biological molecules |
|
|
Term
| what is the mobile phase? |
|
Definition
| where the molecules can move - a liquid solvent, such as ethanol or water |
|
|
Term
| what is the stationary phase? |
|
Definition
| where the molecules cannot move - either chromatography paper (in paper chromatography) or a thin layer chromatography plate (TLC) (often a sheet of plastic coated in silica gel) |
|
|
Term
| where does the mobile phase flow? |
|
Definition
| through and across the stationary phase |
|
|
Term
| the molecules that spend longer in the mobile phase... |
|
Definition
| travel faster and further |
|
|
Term
| explain how you would do paper chromatography |
|
Definition
| 1. draw a pencil line near the bottom of a piece of chromatography paper 2. put a concentrated spot of solution onto line 3. add a small amount of solvent to a beaker and hold the bottom of the paper in it 4. watch the solvent travel up the paper, observe the different constituents of the solution travel up at different rates 5. once the solvent has nearly reached the top, mark the solvent front with a pencil 6. leave paper to dry 7. then use the Rf values to identify the constituents |
|
|
Term
|
Definition
| the ratio of the distance travelled by the spot to the distance travelled by the solvent |
|
|
Term
| what is the formula for the Rf value? |
|
Definition
| distance travelled by spot/distance travelled by solvent |
|
|
Term
| how can we use the Rf value to identify a constituent? |
|
Definition
| look it up in a data base |
|
|
Term
| in chromatography, it can be hard to see the constituents. name 3 and explain 3 ways we can see colourless constituents |
|
Definition
| 1. UV light - TLC plates glow in UV but any constituents on it will not 2. Ninhydrin - shows amino acids by making them brown or purple 3. Iodine - forms a gas which binds to molecules in each spot |
|
|
Term
| how does chromatography work? |
|
Definition
| exposed -OH groups on paper or plate = more polar solutes attract more so move slower and less far than non-polar solutes |
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