Investigating the effect of pH on enzymes [EXPERIMENT] Flashcards

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1
Q

What is amylase?

A

Amylase is an enzyme that catalyses the breakdown of starch and maltose.

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2
Q

What do you use to detect starch?

A

Iodine solution - if starch is present, the iodine solution will change from browny-orange to blue-black.

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3
Q

What is the first step to investigating how pH affects amylase activity using iodine solution?

A

Put a drop of iodine solution in every well of a spotting tile

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4
Q

What is the second step to investigating how pH affects amylase activity using iodine solution?

A

Place a Bunsen burner on a heat-proof mat and a tripod and gauze over it.
Put a beaker of water on top of the tripod and heat the water until it’s 35 degrees.
Use a thermometer to check the temperature and try and keep this temperature throughout the experiment.

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5
Q

What is the third step to investigating how pH affects amylase activity using iodine solution?

A

Use a syringe to add 3cm³ of amylase solution and 1cm³ of a buffer solution with a pH of 5 to a boiling tube.
Using test tube holders, put the boiling water into the beaker of the water and wait for five minutes.

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6
Q

What is the fourth step to investigating how pH affects amylase activity using iodine solution?

A

Using a different syringe, add 3cm³ of a starch solution to the boiling tube.

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7
Q

What is the fifth step to investigating how pH affects amylase activity using iodine solution?

A

Immediately mix the contents of the boiling tube and start a stopwatch.

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8
Q

What is the sixth step to investigating how pH affects amylase activity using iodine solution?

A

Take continuous samples of the solution and record how long it takes for amylase to break down all the starch.
To do this, using a pipette, take a sample of the solution every ten seconds and put a drop into a well.
When the iodine solution remains browny-orange, the starch is no longer present.

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9
Q

What is the seventh step to investigating how pH affects amylase activity using iodine solution?

A

Repeat the whole experiment with buffer solutions with a range of pH values to see how the pH affects the time for the starch to be broken down.

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10
Q

How do you calculate the rate of reaction?

A

Rate(unit time) = 1000/time(seconds)
So for example, if it took 50s for the amylase to break down the starch, the equation would be:
1000/50 = 20sˉ¹

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11
Q

How do you calculate how much something has changed over time?

A

Amount product formed = change
Rate(cm³ sˉ¹) = change/time(seconds)
So for example, if 24 cm³ of oxygen was released in 50s, the equation would be:
24cm³/50s = 0.48cm³ sˉ¹

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