Question

factors that affect enzymes
enzymes are proteins that have a very specific shape. certain factors can have a big impact on the shape of an enzyme molecule and therefore the shape of its active site. a change in the shape of an enzymes active site will affect how well the enzyme can catalyse a reaction. the two main factors which affect enzyme activity are covered below.

key factors that affect enzyme activity

temperature
sketch below the line youd expect to see for the relationship between temperature and enzyme activity

graph with enzyme activity (y - axis) and temperature (°c) x - axis, 40 marked

affect on enzyme activity
words to use: stomach, vibrate, optimum, shape, active, increases, time, denatured, high, acidic, kinetic, decreases

1.) initially as temperature increases, enzyme activity also ______. this is because the enzyme molecules gain more ____ energy and are more likely to successfully collide with the substrate molecules. this leads to more enzyme - substrate complexes being formed and therefore more product is formed in a given ______. the optimum temperature of enzymes in our body is about 40°c.

2.) however, after a certain temperature (about 45°c) the bonds within the enzyme molecule that keep its shape, begin to ______ so violently that they break. this results in the enzyme losing its shape, including the active sites shape. this is called denaturation. as the substrate can no longer fit into the ____ site, the activity of the enzyme dramatically ____. once all the enzyme molecules are ______ the enzyme activity will completely cease.

ph
sketch below the lines youd expect to see for pepsin (optimum ph 2) and amylase (optimum ph 8)

graph with enzyme activity (y - axis) and ph x - axis, 7 marked

all enzymes have an ______ ph that their activity will be highest at. as the ph increases or decreases either side of the optimum ph the enzymes activity will decrease. eventually when the ph becomes too low or high for the enzyme it will denature and lose its ____, just like with ____ temperatures. most enzymes in our body work best at around ph 8. however there are some exceptions. pepsin, found in our ____ has an optimum temperature of about ph 2, which is very ______.

Explanation:

Temperature Section Fill - in - the - Blanks

1.

• First blank: When temperature increases initially, enzyme activity also increases (because molecules gain kinetic energy).
• Second blank: The enzyme molecules gain more kinetic energy (kinetic energy is related to movement, more movement means more collisions).
• Third blank: This leads to more product formed in a given time (rate of reaction is about how much product is formed per unit time).

2.

• First blank: After a certain temperature, the bonds within the enzyme molecule begin to vibrate so violently (vibration of bonds can break them).
• Second blank: The substrate can no longer fit into the active site (active site is where substrate binds).
• Third blank: The activity of the enzyme dramatically decreases (since substrate can't bind, reaction rate drops).
• Fourth blank: Once all enzyme molecules are denatured, activity ceases (denatured enzymes lose their functional shape).

pH Section Fill - in - the - Blanks

• First blank: All enzymes have an optimum pH (optimum is the best condition for activity).
• Second blank: It will denature and lose its shape (same as with temperature - denaturation causes shape loss).
• Third blank: Just like with high temperatures (high temperatures cause denaturation, extreme pH too).
• Fourth blank: Pepsin is found in our stomach (stomach has acidic environment).
• Fifth blank: Which is very acidic (pH 2 is acidic, stomach is acidic).

Temperature - Enzyme Activity Graph Sketch Explanation

• The graph of enzyme activity vs temperature should be a curve that first rises, reaches a peak at around 40°C (optimum temperature), and then falls sharply after 45°C (when denaturation occurs). So on the graph with “Enzyme activity” on the y - axis and “Temperature (°C)” on the x - axis, draw a line that increases from the origin (or a low temperature) up to 40°C, then decreases after 40 - 45°C.

pH - Enzyme Activity Graph Sketch Explanation (Pepsin and Amylase)

• For Pepsin (optimum pH 2): Draw a curve that peaks at pH 2. It should increase from a lower pH (but pH can't be too low, start from a pH above 0) up to pH 2, then decrease as pH moves away from 2 (both increasing and decreasing pH from 2 will decrease activity, and at very extreme pH, it will drop to zero as the enzyme denatures).
• For Amylase (optimum pH 8): Draw a curve that peaks at pH 8. It should increase from a pH below 8 (starting from a reasonable pH, e.g., pH 5) up to pH 8, then decrease as pH moves away from 8 (both lower and higher pH than 8 will decrease activity, and at extreme pH, activity drops to zero). The two curves (Pepsin and Amylase) should be on the same graph with “Enzyme activity” on the y - axis and “pH” on the x - axis, with Pepsin's peak at pH 2 and Amylase's peak at pH 8.

Answer:

Temperature Section Fill - in - the - Blanks

1.

• First blank: When temperature increases initially, enzyme activity also increases (because molecules gain kinetic energy).
• Second blank: The enzyme molecules gain more kinetic energy (kinetic energy is related to movement, more movement means more collisions).
• Third blank: This leads to more product formed in a given time (rate of reaction is about how much product is formed per unit time).

2.

• First blank: After a certain temperature, the bonds within the enzyme molecule begin to vibrate so violently (vibration of bonds can break them).
• Second blank: The substrate can no longer fit into the active site (active site is where substrate binds).
• Third blank: The activity of the enzyme dramatically decreases (since substrate can't bind, reaction rate drops).
• Fourth blank: Once all enzyme molecules are denatured, activity ceases (denatured enzymes lose their functional shape).

pH Section Fill - in - the - Blanks

• First blank: All enzymes have an optimum pH (optimum is the best condition for activity).
• Second blank: It will denature and lose its shape (same as with temperature - denaturation causes shape loss).
• Third blank: Just like with high temperatures (high temperatures cause denaturation, extreme pH too).
• Fourth blank: Pepsin is found in our stomach (stomach has acidic environment).
• Fifth blank: Which is very acidic (pH 2 is acidic, stomach is acidic).

Temperature - Enzyme Activity Graph Sketch Explanation

• The graph of enzyme activity vs temperature should be a curve that first rises, reaches a peak at around 40°C (optimum temperature), and then falls sharply after 45°C (when denaturation occurs). So on the graph with “Enzyme activity” on the y - axis and “Temperature (°C)” on the x - axis, draw a line that increases from the origin (or a low temperature) up to 40°C, then decreases after 40 - 45°C.

pH - Enzyme Activity Graph Sketch Explanation (Pepsin and Amylase)

• For Pepsin (optimum pH 2): Draw a curve that peaks at pH 2. It should increase from a lower pH (but pH can't be too low, start from a pH above 0) up to pH 2, then decrease as pH moves away from 2 (both increasing and decreasing pH from 2 will decrease activity, and at very extreme pH, it will drop to zero as the enzyme denatures).
• For Amylase (optimum pH 8): Draw a curve that peaks at pH 8. It should increase from a pH below 8 (starting from a reasonable pH, e.g., pH 5) up to pH 8, then decrease as pH moves away from 8 (both lower and higher pH than 8 will decrease activity, and at extreme pH, activity drops to zero). The two curves (Pepsin and Amylase) should be on the same graph with “Enzyme activity” on the y - axis and “pH” on the x - axis, with Pepsin's peak at pH 2 and Amylase's peak at pH 8.