Enzyme activity

Question 1

Four factors affect enzyme activity

Answer 1

• enzyme concentration
• substrate concentration
• temperature
• pH

Question 2

How is control set up in practical measuring enzyme activity

Answer 2

• replace the enzyme solution with distilled water
• or boiled enzyme solution

Question 3

Outline the procedure of effect of substrate concentration on enzme activity ussing hydrogen peroxide and catalase

Answer 3

• grind piece of potato cyclinfer of distilled water make past
• transfer 10 cm of hydrogen peroxide to a test tube
• dip a filter paper dissc into enzyme solution and place the disc into hydrogen peroxide solution and measure the tme that taken to float up to ssurface
• removed disk from tube using forceps
• repeat with 4 other concentrations of hydrogen peroxide

Question 4

What is the word equation for the action of catale on hydrogen peroxide

Answer 4

• hydrogen peroxide -> oxygen + water

Question 5

How is the rate of reation calculated from time

Answer 5

• 1/time

Question 6

What is the effect of enzyme concentration on enzyme activity

Answer 6

• as the concentration of enzyme increases successful collusions form enzyme substrate complexes so rate increases to an optimum
• beyond optimum rate plates as substrate concentration beecomes limiting

Question 7

What is the effect of substrate cocentration on enzyme activity

Answer 7

• enzyme activity increases initially as substrate concentration increases as substrate concentration is limiting and hgiher concentration result in more successful collissions to form enzyme substrate complexes
• beyond a certain ssubstrate concentration enzyme activtiy plateus
• as all enzyme active sites are saturated and enzyme concentration is limiting

Question 8

How does phenothaelin indicate rate of enzyme activity using milk and lipase

Answer 8

• as lipase digests lipids in milk into fatty acids and glycerol pH of the solution decreases causing colour change from pink to colourless at end point shorter time faster the rate

Question 9

How is the effect of temperature on lipas activity measured

Answer 9

• prepare water baths with range of temepreatures
• place lipase milk and sodium carbonate in a water bath
• leave for 10 minutes
• mix together start the stopwatch and measure the tim taken for the pink to disappear
• repeat for at least 4 other temperatures

Question 10

What is the effect of temperature on enzyme activity

Answer 10

• increasing temperature increases enzyme activity to an optimum
• enzyme and substtrate molecules gain kinetic energy and move faster so more successul collision to form enzyme substrate complexes
• beyond optimum enzyme activity decreases as hgih temperature disrupts the teritary structure of enzymes and denatures them

Question 11

How does the effect of Ph on enzyme activity investigated

Answer 11

• add fixed volumes of buffeer solutions with a range of pH to trypin and milk at a fixed concentration
• record absrobance immediatley and every 15 seconds for 5 minutes

Question 12

What is the effect of pH on enzyme activity

Answer 12

• enzyme activity is highest at optimum pH
• above or below optimum pH enzyme activity decreases as the unsuitable Ph disrupts its teritary structure and changes shape of its active site causing partial denaturation
• complete denaturation may occur at extreme pH values

Question 13

State a hazrad and saftey precuation involved in this practical

Answer 13

students may have allergic reactions to enzymes
so avoid contract with skin and eyes
wear eye protection