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Three tubes each containing 1ml saliva and 1ml water were incubated in water baths at different temperatures as shown in the diagram below for 30...

      

Three tubes each containing 1ml saliva and 1ml water were incubated in water baths at different temperatures as shown in the diagram below for 30 minutes. Another one tube containing 1ml starch solution was incubated for the same length of time in each water bath. The contents of the two tubes in each water bath was then mixed and incubated for further 30 minutes.The content of each tube was then tested for starch using iodine solution.
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a) What was the aim of the experiment?
(b) Why was it necessary to incubate the tubes for 30 minutes before mixing their contents?
(c) State the colour changes you would expect to observe after adding iodine solution.
(d) Account for the expected observations.

  

Answers


sharon
(a) Effect of temperature on enzymes ;
(b) So that contents of the tubes will have attained the temperature of the waterbath.
(c) A - Would turn blue black
B - Would turn brown / colour of iodine remained
C - Would turn blue black
(d) A - Very low temperature which inactivated enzyme / ptyalin / salivary amylase thus no digestion of starch.
B - Suitable temperature / favourable temperature / optimum / best temperature for activity of enzyme /salivary /amylase / ptyalin thus starch digested.
C - Temperature high / above optimum thus denaturing enzyme thus no digestion of starch.
sharon kalunda answered the question on March 21, 2019 at 14:12


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