# Biology CB1 Enzymes Question Help watch

1. Trying to understand below question. Help will be appreciated.

Q:
- In an investigation 2cm3 of 1% starch solution was mixed with 2cm3 of 1% amylase solution in a test tube.
Every 2 minutes a small amount of the mixture was removed from the tube and tested with iodine solution. (Iodine solution is usually yellow). the table shows the results.

Table image below

-1% starch solution is made by mixing 1g of starch with 100cm3 of water. calculate the rate of reaction of amylase in this investigation in g/min. show your working?

I tried to put the table data here but please let me know if I can provide more information to help answer. Many thanks.

Attachment 724678
2. You've circled 12 minutes so I'm assuming you understand that is the end point of the reaction. To calculate the rate you need this simple formula:

rate = (decrease in reactants) / time taken

Calculate the grams of starch present in 2cm3 and divide this by the time taken to break all of the starch down. Make sure the time is in seconds and give your answer with the units cm3 per second
3. Many thanks for your reply, but I'm not quite sure how to calculate the grams of starch present in 2cm3 (as you suggested).
4. (Original post by HBUT)
Many thanks for your reply, but I'm not quite sure how to calculate the grams of starch present in 2cm3 (as you suggested).
If 100 cm3 water has 1 gram of starch, how many grams will be in 2 cm3 of water? It's a simple ratio question.
5. Ah yes, thank you very much
6. how do you find the decrease in reactants?

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