I don't know some biology questiones(about food test).Please help me. Thx!
1.Do the amounts of the samples used in the food tests need to be measured very accurately?
2.Why is a boilding water bath perferred to a Bunsen flame for heating up the mixture of glucose solution and benedict's solution?
3.How to perfprm Benedict's test on a blood sample?
4.How does the translucent spot caused by lipids differ from the one cauused by distilled water?
Biology Questione
2012-03-25 6:53 am
回答 (2)
2012-03-29 6:04 am
✔ 最佳答案
No. This is because these food tests are qualitative tests for showing the presence of certain food substances. They are not quantitative tests.The water bath has a better control over the temperature and can prevent bumping of the mixture.As the red colour of the blood will mask the results of the Benedict's test, the blood sample should first be diluted with distilled water. Alternatively, the blood sample should be centrifuged and the plasma can be collected for the Benedict's test.The translucent spot caused by lipids is permanent. On the contrary, the translucent spot caused by water disappears as water evaporates.
2012-03-27 6:29 am
1. The amount is not needed to be measured very accurately because the test is to test presence of certain food substance but not its quantity.
2.Bunsen flame provide vigorous heating while boiling water bath provides slower temperature change.
3.Use a centrifuge to obtain the blood plasma in blood sample.
Perform Benedict's test as usual.
4.The translucent spot caused by lipids are soluble in organic solvent
2.Bunsen flame provide vigorous heating while boiling water bath provides slower temperature change.
3.Use a centrifuge to obtain the blood plasma in blood sample.
Perform Benedict's test as usual.
4.The translucent spot caused by lipids are soluble in organic solvent
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