Enzyme activity using the enzyme catalase in different plant sources

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Title: Enzyme activity using the catalase enzyme in different plant sources

Background information:

Enzymes are biological catalysts. They are made of protein. They speed up the rate of reaction in the body and without taking part in the reaction. The surface of the enzyme where the substrate binds to is called the active site, which has a specific conformation. Normally the active site is enzyme-substrate specific. This is explained by the lock and key theory, where the enzyme is the lock and the substrate is the key.

Enzyme activity, specifically is the rate at which the enzyme catalyses the chemical reaction. This is affected by three main factors: 1) temperature, 2) pH and 3) substrate concentration. Another factor is the enzyme concentration but it is not included in the syllabus.

Hydrogen peroxide is a weak acidic but has very strong oxidizing properties. It is a by-product of respiration thus very harmful to cells. Hydrogen peroxide is catalysed by the enzyme catalase to form water and oxygen in the body as soon as possible:

2H2O2 (l)        catalase        2H2O (l) + O2 (g)

The enzyme catalase can be found mostly in liver cells and in potato and many other plant foods.

AIM:

To investigate the oxygen collected in hydrogen peroxide using different sources of plant food samples.

Research question

Investigating how will the height of foam (showing oxygen collected) differentiate the activity of the enzyme catalase using different plant sources (potato, apple, onion, beetroot, carrot) at optimum temperature (37oC) in a period of 20 minutes?

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Apparatus

  • 5 different food samples (plant type)
  •  125 cm3 Hydrogen peroxide (one typical concentration)
  • 2 Stopwatch(±              )
  • 1 Thermometer(±0.5oC )
  • 1 Beaker
  • 2 test tube rack
  • 25 test tubes
  • 1 Kettle
  • 1 Cutter
  • Ice
  • 1 Marble to cut the food samples
  • Aluminium foil
  • 1 dropper (±0.25cm3 )        
  • 1 measuring cylinder (± 0.2cm3)
  • Ruler (±0.5 mm)
  • 5 petridishes
  • 1 cork borer

Procedure (HINT: read through the whole procedure before starting the experiment)

  1. Prepare all your materials on your ...

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