Experiments on Digestion

Q. Which of the following is used to test the presence of starch?

1. Sodium Chloride Solution
2. Red Litmus Solution
3. Blue Litmus Solution
4. Iodine Solution

Q.

Which material is required to make a dilute iodine solution?

Q.

You have been supplied with a sample of food. How will you perform tests for the presence of starch and proteins in it ?

Q.

Sudha took a small amount of an unknown food item in a test tube. Then, she added a few drops of iodine to it. The colour of the unknown food item changes to blue-black.

The change in colour of the food item to blue-black indicates the presence of

1. Carbohydrates

2. Vitamins

3. Fats

4. Proteins

Q.

A solution was dropped over a slice of potato. It turned blue-black. The solution was

1. Iodine solution

2. Metanil solution

3. Benedicts solution

4. HCl

Q. Some pieces of potato fries are placed on three plates as shown below. In plate A, water is added. In plate B, saliva is added and mixed thoroughly. Nothing is done to the fries in plate C.

The plates are undisturbed for 1 hour. A few drops of iodine is added to each plate. In which plate will the iodine remain brown?

1. Both B and C
2. B only
3. Both A and B
4. A only

Q. Starch is not found in:

1. Cereals
2. Wheat
3. Milk
4. Rice

Q.

In the experiment for testing the action of pepsin on egg-white, we concluded that

1. Pepsin can digest protein only in acidic conditions.

2. If acid is added in higher concentration, it can digest protein alone.

3. Boiled pepsin becomes inactive and hence fail to digest protein.

4. Pepsin alone can also digest protein.

Q.

Which of the following is false?

1. Fehling's solution is blue in color.

2. The starch solution turns blue on adding Fehling's solution to it.

3. Fehling's solution turns brick red in presence of saliva.

4. Fehling's solution helps in testing the action of saliva on starch.