enzymes (chapter 4)

Question 1

temperature

Answer 1

• increasing the temperature of a reaction enviroment increases kinetic energy of the particles
• particles move faster which leads to more sucessful collisions between substrate and enzyme. This leads to an increase in the rate of reaction.

Question 2

the temperature coefficient

Answer 2

a measure of how much the rate of reaction increases with a 10 degree rise in temperature.

Question 3

denaturation from temperature

Answer 3

• as enzymes are proteins their structure is affected by temperature.
• at higher temperature the bond holding the protein together vibrate more, as the temp increases the vibrations increase until the bonds strain and then break.
• the breaking of the bonds result in a change in the precise tertiary structure of the protein.
• the enzyme has changed shapes and is said to be denatured.

Question 4

optimum temperature

Answer 4

• the OT is the temperature at which the enzyme has the highest rate of activity, this can vary.
• many enzymes in the human body have optimum temperatures of around 40 degrees, enzymes in hot springs have an OT of around 70 degrees, enzymes found in cold enviroments have OT of temperatures below 5 degrees.
• enzymes that denature above the optimum temperature the decrease in rate of reaction is rapid as the active site changes shape, the decrease in rate of reaction below optimum temperature is less rapid as the active site hasnt changed shape, they are just less active.

Question 5

pH

Answer 5

• hydrogen bonds and ionic bonds betwee amio acid R-groups hold proteins i their precise three dimensional shape.
• a change in pH refers to change in hydrogen ion concentration, more hydrogen ions are present in low pH (acid) enviroments and less hydrogen ions are present in high pH (alkaline) enviroments.
• If the pH becomes too alkaline or too acidic then the shape of the active site is altered, however if the pH returns to the optimum then the protein will resume its normal shape.
• The more hydrogen ions present (low pH), the less the R-groups are able to interact with eachother.