Expert: Walter Hintz - 10/27/2006

Question
here is the detail
we were to do amylase activity test
for that
step1
tube1 :add 6ml of amylase solution
tube2 : add 6 ml of starch solution
tube 3 : add 5 ml of starch solution and 1 ml of amylase solution
step2
put these tube in warm bath 37'C for 10 min at the end of 10 min place 1 ml of solution to be tested in a depression of porcelain plate ,next add one drop of iodine-potassium -iodide solution and record the result .
step 3
now test for the presence odf sugar for that place 1 ml of solution to be tested in a clean test tube .
add 1 ml of benedicts solution and then place the tube in a boilong beaker for 2 min and record the change in color and record the result.
so the result were
TUBE          STARCH          SUGAR
Amylase solution          negative          negative(blue)
starch solution          positive          negative(blue)
starch-amylase solution    positive          positive(orange

now the questions were
1- explain the reason for including tube 1 (amylase solution )in this experiment ?
2- what is the importance of tube 2 (starch solution)?
3- what do u conclude from the result of the experiment ?

even in part B we have to test the effect of heat :
in this part
step 1
make 3 tube each having 1 ml of amlyase solution and then
put tube 4 in a ice water beaker for 3 min .
tube 5 in warm water bath 37'C for 3 min
tube 6 in boiling water  for 3 min.
step 2
after 3 min add 5 ml of starch solution to each tube and then return the tube to their respective temperature for 10 min .
step 3
at the end of 10 min test the content of each tube for the presence of starch by puting drop of iodine-potassium -iodide and sugar with benedicts solution .
record the result .

result
TUBE          STARCH          SUGAR
4-  at 0 'C          positive         positive(yellow)
5-  at 37'C          negative         positive(orange)
6-  at 100'C          positive         negative(blue)

the question for this section of experiment is
1- what do u conclude from the result of this experiment ?
2- if digestionn failed to occur in one tube in this experiment ,how can u tell if the amylase was destroyed by the factor beign tested or if the amylase activity was simply inhibited by the test treatment ?
3- what test result would occur from above all test if amylase you used contain sugar? explain?
this is the whole detail of the experiment.
thanks
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The text above is a follow-up to ...

-----Question-----
hi!
i perform this lab but can not solve the question given below .
the practical was amylase activity test with iodine and benedicts reagent and the results were

tube 1  amylase solution      starch -ve        sugar -ve
tube 2  starch solution       starch +ve        sugar -ve
tube 3   starch-amylase solution  starch +ve    sugar+ve   

the question were
1- explain the reason for including tube 1 in this experiment?
2-  explain the importance of tube 2?
3- what do u conclude from the experiment result ?
4- if amylase used contained sugar what the result be ?

thanks
-----Answer-----
Could you give me a bit more information?
what is the + and - ve

Answer
 Hi Musqus
Tube 1 is a control
Tube 2 indicated the presence of starch but no sugar
Tube 3 indicated that amylase broke starch down to sugar
 If amylase contained only sugar the blue color would not appear.

The tubes 4,5,6 tested the effects of temperature upon amylase.
 At 0 C The action is slow but some didestion occured
 At 37 C (body temperture) digestion occurs the best
 At 100 C the enzyme is deactivated and does not digest starch

   Conclusions
         Salivary amylase converts starch to sugar at 37 degrees C