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Enzymes SQA Questions What you should know - ENZYMES atalyst • A c________ is a substance which helps to s______ up a chemical reaction. It remains peed u________ nchanged at the end of the reaction. • An enzyme is a p_______ which can act as a rotein iological catalyst inside l_____ (b_______ iving c_____ ells c_________). atalysts • Enzymes are important for the functioning of living cells because w_______ the aid of e________ the ithout nzymes chemical reactions would take place too s______ to lowly maintain life. • Enzymes in a cell are used in ‘b________’ reakdown or ‘s_______’ ynthesis • Breakdown is when an enzymes breaks down a arge l______ s________ ubstrate molecule into s______ maller ones • Synthesis is when an enzyme j_____ oins s______ maller substrate molecules t_________ to make a ogether larger one • P_______ and c__________ are examples of epsin atalase breakdown enzymes hosphorylase • P______________ is a synthesis enzyme pecific • Enzymes are s________ – they will act only on ne s__________ ubstrate o___ roteins • Enzymes are p________ emperature and __. pH • Enzymes are affected by t__________ Enzymes revision 1 ells hemical eactions ynthesis lucose tarch egradation atalase xygen ock ey pecific changed emperature ptimum enatured epsin 7 Effect of temperature on enzyme activity Enzyme activity increases rapidly Maximum enzyme activityoptimum temperature Enzyme is being denatured the temperature at which the enzyme has greatest activity the pH at which the enzyme has greatest activity catalase pepsin 1 2 4 7 9 11 8. Pepsin pH4 pH1 to _____. • has a working range of ____ is active between ph 1 and 4 • This means it ______________________ pH2 • Pepsin has an optimum pH of ____. This maximum ________ activity means it has ________ at pH 2 9. Catalase pH7 to _____. pH11 • has a working range of ____ is active between ph 7 and 11 • This means it ______________________ pH9 • Catalase has an optimum pH of ____. This maximum ________ means it has ________ activity at pH 9 1 2 catalase 5 starch 3 breakdown 6 phosphorylase 7 8 synthesis 9 Fatty acids + 10 Fat 11 glycerol 12 4 breakdown 13 14 breakdown 15 breakdown Enzymes revision 2 Speed up reactions Unchanged at the end of reaction Lower the energy needed for a reaction biological Chemical reactions Unchanged at end of reaction synthesis degradation temperature specific pH Control experiment ontrol • A c______ experiment is set up to prove esults actor that the r______ are due to the f______ nvestigation (v_________) under i___________ ariable Aim: An investigation is set up to prove that starch is digested by amylase enzyme to maltose sugar Draw and describe the control tube Test tube containing 2ml amylase(5% concentration) + 5ml starch solution(10% concentration) Experiment carried out in a water bath at 37ºC Q. In this investigation, what is the purpose of the control experiment The control p______ roves that starch digestion o___ nly occurs when a_______ mylase is present Test tube containing • equal volume of water (2ml) •equal volume of starch solution (5ml) •equal concentration of starch solution ( 10% concentration) Same temperature ( 37ºC), same type of • Aim: An investigation is set up to prove that starch is synthesised by phosphorylase enzyme from glucose 1 phosphate • Draw and describe two control tubes 1cm3 glucose 1 phosphate (3%) 1cm3 phosphorylase enzyme (1%) experiment carried out at room temperature (25ºC) 1cm3 glucose 1 phosphate (3%) 1cm3 distilled water experiment carried out at room temperature (25ºC) AND 1cm3 phosphorylase enzyme (1%) 1cm3 distilled water experiment carried out at room temperature (25ºC) Reliability epeating ncreases • R_________ an experiment i_________ eliabilty esults R R R r________ of r_______ (__,__.__) • This shows that results are not nrepresentative or a ‘o___ ne o___’ ff u___________ verage • Often an a________ is then calculated Averages Temperature (°C) Bubbles (number/s) 10 20 30 40 50 4 8 14 4 0 To find the average number of bubbles … 1. Find the total number of bubbles 2. = 30 4 + 8 + 14 + 4 + 0 Divide the total by the number of items There are 5 items in the table 30 5 = 6 3. Don’t forget units in your answer Average = 6 bubbles/s Try this example … Temperature (°C) Bubbles (number/s) Click here for answer 10 20 30 40 50 0 2 8 3 2 15 ÷ 5 = 3 bubbles/s Percentages Temperature (°C) Bubbles (number/s) 10 20 30 40 50 4 8 16 4 0 To find the percentage of bubbles at 20ºC … 1. Find the total total number of bubbles 2. 4 + 8 + 16 + 4 + 0 = 32 Divide the number of bubbles at 20ºC by the total number 8 32 = 0.25 this is the decimal fraction 3. Multiply the decimal fraction by 100 to get the percentage 0.25 x 100 = 25% 25% of the bubbles are produced at 20ºC What percentage of bubbles are produced at 30ºC? 16 32 = 0.5 x 100 = 50% 10ºC? 4 32 = 0.125 x 100 = 12.5% Ratios Temperature (°C) Bubbles (number/s) 10 20 30 40 50 4 8 14 4 2 To find the simple whole number ratio of bubbles at 10 degrees compared to bubbles at 20 degrees … 1. Write down the ratio of the numbers 10ºC 4 bubbles 2. : : Find a number that will divide into both numbers to give a whole number – in this case 2 4 bubbles 2 = 2 bubbles 3. 20ºC 8 bubbles : : 8 bubbles 2 4 bubbles Repeat step 2 until you cannot divide again without getting a fraction 2 bubbles 2 = 1 bubble : : 4 bubbles 2 2 bubbles Ratios Temperature (°C) Bubbles (number/s) 10 20 30 40 50 4 8 14 4 2 To find the simple whole number ratio of bubbles at 20 degrees compared to bubbles at 30 degrees … 1. Write down the ratio of the numbers 20ºC 8 bubbles 2. 30ºC 14 bubbles Find a number that will divide into both numbers to give a whole number – in this case 2 8 bubbles 2 = 4 bubbles 3. : : : 14 bubbles 2 : 7 bubbles You cannot divide any more without getting a fraction so … the simple whole number ratio is: 4 : 7 apple liver Equal mass of tissue Same temperature Equal concentration of hydrogen peroxide Same apparatus with dead tissue Improves reliability 3 5 1 Optimum pH specific 6 √ 30 55 - 60 specific 45