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Biology - Enzymes help? Watch

    • Thread Starter

    Students mixed a starch solution with amylase. They recorded the concentration of maltose at intervals for 20 minutes.
    1) Why is the rate of reaction lower after 10 minutes than it was at 5 minutes.
    2) Why is there no further increase in maltose concentration between 15 and 20 minutes.

    Please explain to me as i'mm not sure . Is 1) That at 5 minutes there's more substrate therefore a higher chance of a collision but at 10 minutes the more active site is being ocupied so it's harder for a colision to occur. Is that right?
    • Official TSR Representative

    Sorry you've not had any responses about this. Are you sure you've posted in the right place? Here's a link to our subject forum which should help get you more responses if you post there.

    Just quoting in Alisaurus Cats so she can move the thread if needed :wizard:
    (Original post by Alisaurus Cats)


    Rate of enzyme-activated reaction depends on a few factors: Temperature, substrate conc, pH, product conc.

    1. At 10 minutes there is less substrate remaining as part has been "digested" to maltose therefore (you are correct), less actve site/substrate collisions.

    2. The graph of enzyme activity (y axis) against time (x axis) always levels out and eventually becomes almost horizontal (negative exponential in later stages) because any reaction is dynamic i.e. an enzyme can make a reaction go in either direction depending on the factors above. So, at 15-20 minutes, a) there is hardly any substrate left, so rate of reaction tends to zero.

    Name:  Rate Equation.jpg
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    where R = rate of reaction (in this case, rate of maltose production) [A] = concentration of substrate, in this case starch.

    Good luck!

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