PAPER 6 Biology IGCSE 0610

What is an INDEPENDANT variable?

• The variable that is changed by the investigator

• A variable that changes and is measured

• A variable that should be kept constant so as to not affect the result of the dependant variable

What is a DEPENDANT variable?

• The variable that is changed by the investigator

• A variable that changes and is measured

• A variable that should be kept constant so as to not affect the result of the dependant variable

What is a CONTROL variable?

• The variable that is changed by the investigator

• A variable that changes and is measured

• A variable that should be kept constant so as to not affect the result of the dependant variable

How can you make an experiment more RELIABLE?

• Do it 3 times and then take an average.

• Use the same type of sample.

• Exclude anomalies from data.

• Use appropriate apparatus

How can you make an experiment VALID?

• Do it 3 times and then take an average.

• Use the same type of sample.

• Use the same volume of solution.

• Use appropriate apparatus

How can you make an experiment more ACCURATE?

• Do it 3 times and then take an average.

• Use the same type of sample.

• Use the same volume of solution.

• Use appropriate apparatus

How many decimal places should you answer with?

• 1 decimal place even if the rest of the table is a whole number

• A whole number even if the rest of the table is to 1 decimal number.

• If the rest of the table is to 1 decimal place then you should answer with 1 decimal place even if your answer is a whole number.

• If the rest of the table is a whole number, then you should answer with 1 decimal place even if your answer is a whole number.

What is the test for Starch?

• Add a few drops of Iodine Solution, gently shake, it should turn from brown/orange to blue/black

• Add a few drops of Biuret Reagent, gently shake, it should turn from blue to mauve/purple

• Add 2cm³ Benedict's Reagent, heat/boil, it should turn from blue to green to yellow to orange to red

• The emulsion test: Add 2cm³ of ethanol to the unknown solution, gently shake, pour into equal volume of distilled water. If present a milky-white emulsion is formed.

What is the test for Reducing Sugars?

• Add a few drops of Iodine Solution, gently shake, it should turn from brown/orange to blue/black

• Add a few drops of Biuret Reagent, gently shake, it should turn from blue to mauve/purple

• Add 2cm³ Benedict's Reagent, heat/boil, it should turn from blue to green to yellow to orange to red

• The emulsion test: Add 2cm³ of ethanol to the unknown solution, gently shake, pour into equal volume of distilled water. If present a milky-white emulsion is formed.

What is the test for Fat (Lipids)?

• Add a few drops of Iodine Solution, gently shake, it should turn from brown/orange to blue/black

• Add a few drops of Biuret Reagent, gently shake, it should turn from blue to mauve/purple

• Add 2cm³ Benedict's Reagent, heat/boil, it should turn from blue to green to yellow to orange to red

• The emulsion test: Add 2cm³ of ethanol to the unknown solution, gently shake, pour into equal volume of distilled water. If present a milky-white emulsion is formed.