Junior Certificate Science Experiments for Biology

Biochemical Tests
Describe how to carry out the 5 key biochemical tests:
Iodine test for starch

1. Add iodine
2. Look for colour change to blue-black.

Benedict’s test for reducing sugars or glucose

1. Add Benedict’s solution.
2. Heat in a water bath.
3. Look for colour change to brick-red.

Benedict’s test for non-reducing sugars
After an initial negative Benedict’s result.

1. Heat with dilute acid.
2. Neutralise with dilute base.
3. Add Benedict’s solution and heat.
4. Look for colour change to brick-red.

Biuret test for protein

1. Add Biuret solution.
2. Look for a colour change to lilac.

Emulsion test for lipids or fats

1. Add ethanol.
2. Add water.
3. Look for milky-white precipitate.

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Energy Content of Food
In this experiment we measure the temperature change in a can of water to determine the energy content of the food being burned below it.
A calorie is the amount of energy required to raise the temperature of 1 gram of water by 1°C.

Energy stored within a food item (like a marshmallow) will be released if the food is burned. A can with water will be placed just above the burning food. The amount of energy released from the food will be determined by calculating the energy gained by the water in the can.

The can will contain 50mL of water. A temperature probe will monitor the temperature change in the water. The calories gained by the water in the can is equal to the
mass of water × change in temperature of water.

Experiment to compare the energy content of peanuts and marshmallows.

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Measuring the energy in food
Experiment using a food calorimeter
1 gram of potato: Change in temperature from 21°C to 25°C
1 gram of peanut: Change in temperature from 21°C to 29°C

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Action of Amylase on Starch

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Carbon Dioxide Levels of Inhaled and Exhaled Air
In this experiment we will investigate the carbon dioxide levels of inhaled and exhaled air. We use limewater to test for the presence of carbon dioxide.

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Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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