In a physiological experiment, starch, protein, diastase and sodium chloride (common salt) were added to water and put inside a visking tubing. The visking tubing was...

      

In a physiological experiment, starch, protein, diastase and sodium chloride (common salt) were added
to water and put inside a visking tubing. The visking tubing was then placed in a water bath maintained at a temperature between 350C and 400C. The set-up was as shown in the diagram below.
52920191401.png
The following observations were made after the procedures indicated.
52920191403.png
(a) Name the process by which salt moved into the water in the beaker from the visking tubing.
(b) (i) Name the food substance responsible for the brown colour observed after one hour both in the beaker and visking tubing when solutions were boiled with Benedict’s solution.
(ii) Account for the observation in b(i) above.
(c) (i) Name the food substance tested with sodium hydroxide followed by copper sulphate solutions.
(ii) Account for the absence of the food substance named in c(i) above in the beaker after1 hour.
(d) After one hour, the visking tubing was firm. State the term used to describe this state.

  

Answers


sharon
(a) Diffusion ;
(b) (i) Reducing sugars / simple sugars / glucose ;
(ii) Diastase converts starch to reducing sugars ; So present in visking tubing. Due to their small size and semi-
permeability of the visking tubing ;the molecules moved across the semi-permeable wall of visking to the beaker ; so present in the beaker.
(c) (i) Proteins.
(ii) Proteins are large molecules / big size molecules so cannot pass through the pores of the visking tubing ;
(d) Turgid/turgidity.
sharon kalunda answered the question on May 29, 2019 at 11:07


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