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Define a monomer?
~ one of many small molecules that combine to form a larger one known as a polymer
Define a polymer?
~ large molecule made up of repeating smaller molecules(monomer)
4 examples of monomers?
~ Monosaccharides- Glucose, galactose ~ Nucleotides ~ amino acid ~ fatty acid or glycerol
Define a hydroylsis reaction?
~ the breaking down of large molecules into smaller ones by the addition of water molecules
Define a condensation reaction?
~ chemical process in which 2 molecules are combine to form to form more complex one with the elimination of a simple substance usually water. polymers are form through this reaction.
Define monosaccharides?
~ A monomer of carbohydrates
Define dissacharides?
~ A molecule that is made up of two monosaccharides
Define polysaccharides?
~ A molecule formed from more than two monosaccharides
Draw a Beta glucose?
Draw alpha glucose?
What type of sugar is a glucose?
~ Hexose sugar
What is a Sucrose made up of?
~ Fructose & Glucose
What is Maltose made up of?
~ Glucose & Glucose
What is Lactose made up of?
~ Glucose & Galactose
Draw a condensation reaction between 2 alpha glucoses?
Describe the structure of amylose?
~ Long, unbranched chains of α-glucose ~ Angles of glyosidic bonds makes it a coiled structure - this makes it compact and good for storage ~ Amylose is insoluble so does not effect water potential ~ Contain 1-4 glyosidic bonds
Describe the structure of amylopectin
~ Long, unbranched chains of α-glucose ~ Has side branches which allows enzyme to hydrolyse bonds more easily - glucose is released quickly ~ Amylopectin is insoluble so does not effect water potential inside a cell ~ Contain 1-4 glyosidic bonds ~ Branches with 1-6 glyosidic bonds
Function of amylopectin & amylase?
~ Cells get energy from glucose ~ Plants store excess glucose as starch - when glucose is needed the starch is broken down
Draw amylopectin & amylase?
Structure and function of Glycogen?
~ shorter , unbranched chains of α-glucose ~ highly unbrached chains amylopectin ~ Very compact molecule so good for storage ~ Glycogen is insoluble so does not effect water potential inside a cell ~ Smaller chains of 1-4 glyosidic bonds functions: Loads of side branches means that glucose can be released quickly to provide energy ~ Way excess glucose is stored in animals storage for excess sugar in liver
Function of Glycogen?
storage for excess sugar in liver
Describe the structure of cellulose?
~ Long, unbranched chains of β-glucose ~ Glyosidic bonds makes a straight chained molecule ~ Cellulose chains are linked together by hydrogen bonds - forming microfibrils ~ Microfibrils are further bunched together to form macrofibrils
Function of cellulose?
~ The strong macrofibrils means cellulose provides structural support for cells - cell walls for cells are turgid
Biochemical test for a reducing sugar?
~ Add benedicts reagent and heat it in a water bath ~ Positive result will form a brick red precipitate
Biochemical test for a non-reducing sugar?
If test for reducing is negative then do this: ~ Add dilute hydrochloric acid to the sample and heat it in a water bath - to break non-reducing sugars down into monosaccharides ~ Neutralise with sodium hydrocarbonate ~ Carry out Benedict's test
What is a reducing sugar?
~ All monosaccharides ~ Some disaccharides - Maltose & Lactose
What is a non-reducing sugar?
~ Some disaccharides like sucrose
How to evaluate the concentration of reducing sugar?
~ Filter the solution and weigh the precipitate ~ Remove the precipitate and use a colorimeter to measure the absorbance of light of remaining solution - Each colour of precipitate lets a certain amount of light through
Describe the test for starch (E.g. amylopectin & amylose)?
~ Add iodine dissolved in potassium iodide solution to the sample ~ Positive result means it will go from browny-orange to a blue-black colour
Describe the structure of triglycerides?
~ Have one molecule of glycerol with 3 fatty acids attached ~ Fatty acids made of hydrocarbons ~ The tails are hydrophobic so makes triglycerides insoluble
How does a monosaccharide form?
~ Joined by a condensation reaction forming a glyosidic bond ~ A molecule of water is released
Draw a triglyceride - simple version?
What is the general structure of a fatty acid?
Draw A triglyceride - complex version?
Describe the differences between a saturated and unsaturated fatty acid?
~ Saturated fatty acids don't have any double bonds between their carbon atoms while a unsaturated does
Draw a saturated and unsaturated fatty acid?
How is a triglyceride formed?
~ By a condensation reaction between fatty acids and a glycerol ~ Ester bond is formed and a molecule of water is removed
Draw the condensation reaction of the formation of a triglyceride?
Draw a diagram of a phospholipid?
Where are the hydrophobic & hydrophilic regions on a phospholipid?
~ Hydrophobic fatty acid tail ~ Hydrophilic phosphate group
Describe the test for lipids?
Called the emulsion test ~ Shake the test substance with ethanol and then pour into water ~ Any lipids present will show up as a white emulsion ~ The greater the presence of emulsion means more lipids present
Relate the structure of triglycerides to their function?
~ Mainly used a energy storage molecules - good because they have long hydrocarbon tails which contain lots of chemical energy. When broken down they release twice as much energy as carbohydrates ~ They are insoluble in water so do not effect water potential - which causes water to enter by osmosis - As triglycerides bundle into insoluble droplets as the tails are hydrophobic
Draw a insoluble triglyceride droplet?
Relate the structure of a phospholipid to its function?
~ Make up a bilayer of cell membranes controlling what enters and leaves cell - As the tails are hydrophobic so point inwards and the heads a hydrophilic so point into water. ~ So allows membrane to be a barrier as water-soluble substances can't easily pass through
Draw the general structure of a amino acid?
How many different types of amino acids are there?
~ Only 20 different types
Define polypeptide?
~ A molecule formed from more than 2 amino acids bonded by peptide bonds
Bonds in carbohydrates?
~ Glyosidic bonds
Bonds in Lipids?
~ Ester bonds
Bonds in proteins?
~ Peptide bonds
Define dipeptide?
~ A molecule formed from two amino acids
Define protein?
~ Proteins are large macromolecules consisting of more than one amino acid chain
Define Peptide?
~ Short chains of more than two amino acids bonded in a chain
Draw the formation of dipeptides from amino acids?
~ Reaction not revisible
Describe how dipeptides are formed?
~ Amino acids are linked by condensation reactions to form dipeptides ~ Forming a peptide bond and a molecule of water
Describe the primary structure of a protein and name the bonds?
~ A sequence of amino acids in a polypeptide chain ~ Contains peptide bonds
Draw the primary structure of a protein?
Describe the secondary structure of a protein and name the bonds?
~ Hydrogen bonds form between amino acids ~ This makes primary structure automatically coil up into a α-helix or fold into a β-pleated sheet
Draw a β-pleated sheet and α-helix?
Describe the tertiary structure of a protein and name the bond involved?
~ Amino acid chain is coiled or folded further ~ Hydrogen bonds, Ionic bonds and disulphide bridges form ~ Disulphide bridges form where two molecules of cytosine come very close and their sulphur atoms bond ~ Hydrophobic interactions form between non-polar R groups ~ Made of single polypeptide chain
Draw the structure of a tertiary protein?
Describe the quaternary structure of a protein and name the bonds involved?
~ Made up of several polypeptide chains bonded together ~ Quaternary structure depends on primary structures ~ Examples of bonds: Hydrogen bonding and Disulphide bonds
Draw a quaternary structure of a protein?
Overall sequence of shapes formed in a protein?
Relate the structure of proteins to their function?
~ Enzymes - spherical due to tight folding of polypeptide chain. They are soluble and often used in metabolic processes ~ Antibodies - made up of 2 light and 2 heavy polypeptide chains. Have a variable region where the amino acid sequence greatly varies ~ Transport proteins - Channel proteins contain hydrophobic and hydrophilic amino acids causing it to fold up into a channel ~ Structural proteins - are physically strong as consist of long polypeptide chains parallel with each other, with cross-links between them.
Describe the structure of Collagen?
~ Has 3 polypeptide chains coiled around each other in a triple helix with cross-link which are covalent bonds makes it strong ~ Every 3rd amino acid is glycine ~ Used in supportive tissue
Describe the biurets test?
~ Solution must be alkaline so add few drops of sodium hydroxide ~ Add some Copper(II) sulphate ~ If the solution turns purple then a protein is present, no proteins it will stay blue
What do enzymes do?
~ Lower the activation energy of a reaction in metabolic reactions
Describe the induced-fit model?
~ Substrate collides with active site ~ The tertiary structure of the active site is able to combine with complementary substrates ~ The active site changes to fit more closely around the substrate - held in position by oppositely charged R-groups ~ Enzyme-substrate complex forms ~ Change in shape puts strain on the bonds, weakening them, so lowers the activation energy ~ Enzyme-product complex forms and the substrate no longer fits so is released
How come the enzyme binds to the substrate?
~ Because the tertiary shape of the active site is complementary to the shape of the substrate ~ So can form a enzyme substrate-complex
Why does a enzyme-substrate complex lower activation energy?
~ Being close together reduces any repulsion between the molecules allowing them to bond more easily ~ Active site puts strain on the bond
Explain why enzymes are so specific?
~ Because only one complementary substrate will fit into the active site. ~ Each enzyme has a different tertiary structure which is determined by primary structure so has a different shaped active site ~ If substrate does not match the shape a enzyme substrate complex will not form
Methods of measuring enzyme activity?
~ How fast product is made ~ How fast substrate is broken down
Annotate a graph about how temperature effects the rate of a enzyme controlled reaction?
Explain how temperature effects the rate of a enzyme controlled reaction?
~ More heat means increase kinetic energy, so molecules move faster ~ Substrate is more likely to collide with enzyme and more energy involved in each collision so more likely to be above activation energy ~ Very high temperatures makes the enzyme's molecules vibrate more - vibrations break weaker ionic and hydrogen bonds ~ Tertiary structure changes so enzyme is denatured
Annotate a graph about how pH effects the rate of a enzyme controlled reaction?
Explain how pH effects the rate of a enzyme controlled reaction?
~ All enzymes have a optimum pH value ~ Above and below the optimum OH- and H+ ions can disrupt ionic and hydrogen bonds that hold tertiary structure ~ Tertiary structure changes - enzyme denatures
Annotate a graph about how Enzyme concentration effects the rate of a enzyme controlled reaction?
Explain how Enzyme concentration effects the rate of a enzyme controlled reaction?
~ The more enzymes there are the more likely it is for a substrate molecule to collide - forming a enzyme substrate-complex ~ If the amount of substrate is limited, there comes a point where all the active sites are full
Explan how Substrate concentration effects the rate of a enzyme controlled reaction?
~ More substrate is more likely to collide with the active site - more enzyme substrate-complexes form ~ Reaches a 'saturation point' where all the active sites are full so graph levels off
Describe the action of a competitive inhibitor?
~ Have a similar shape to the substrate ~ They compete with the substrate to bind with the active site ~ They block the active site so no enzyme substrate complexes can form
Describe the action of a non-competitive inhibitor
~ Molecules that bind away from the active site at the allosteric site ~ Distorts the active shape so substrate is no longer complementary to the active site
Annotate a graph about how Non-competitive inhibitors effects the rate of a enzyme controlled reaction?
Annotate a graph about how Competitive inhibitors effects the rate of a enzyme controlled reaction?