• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Induction of Beta-Galactosidase

Extracts from this document...

Introduction

Induction of �-Galactosidase Hypothesis I believe that �-Galactosidase will only be induced in the test tube containing the bacteria grown in lactose as �-Galactosidase is the enzyme that breaks down lactose. Variables My dependent variable, which is what I will be measuring, will be the presence of the enzyme �-galactosidase. My Independent variable will be the addition of lactose to a culture of E-coli. I will also have two control experiments to be able to compare the extremes. One with �-galactosidase originally present and the other with no bacteria present. Planning Genes are expressed in cells when the coded protein products are needed. This conserves the energy in the cell. E-coli uses carbohydrates as a food source. If lactose, found in milk, is in the E-coli growth medium it must be broken down into glucose and galactose before it can be used in respiration. This bacteria contains encoded in it a gene for the enzyme �-galactosidase which breaks down lactose. ...read more.

Middle

Keep away from flames. The vapour causes irritation to the eyes and evaporation should only take place in a fume cupboard. Avoid contact with skin and eyes; eye protection must be worn. Aseptic techniques must be used to avoid any contamination due to spillage of micro-organisms. Any spills should be dealt with immediately and correctly. No eating or drinking anywhere near the experiment. Cover all skin cuts with a waterproof plaster. Be sure to wipe all surfaces down with disinfectant and wash hands with soap and water before the practical. Aseptic techniques All equipment should be sterile before usage. (Autoclave glassware; using a low Bunsen flame to decontaminate glass, metal wire before the transfer of bacteria and wash plastic with 70% ethanol.) This is to avoid cross-contamination between equipment. Make sure to place all used equipment straight into disinfectant after use. After I have done this experiment I will compare the colour of the solution in the test tubes. A yellow colour will show the presence of the enzyme �-galactosidase. ...read more.

Conclusion

This bacteria contains encoded in it a gene for the enzyme �-galactosidase which breaks down lactose. The presence of lactose activates this gene so the enzyme is then produce. This proves that genes can be "switched on and off" (called de-repression). The lack of lactose will therefore deactivate the gene co the enzyme is not produced. These results are reliable. The experiment was repeated eight times each giving the same results. The results were done by eye, quantitatively rather than qualitatively, so this could be classified as a limitation. This could be overcome by using a colorimeter to generate qualitative results to clarify definite values. In summary, I planned an investigation to find out whether �-Galactosidase will only be induced in the presence of lactose. �-Galactosidase is the enzyme that breaks down lactose into glucose and galactose. To find this out I used two types of E coli, one bred in the presence of lactose and one bred without lactose. My results concluded that the �-Galactosidase was only induced with lactose present. (The solution turned yellow) This, in conclusion, proved to me that genes can be switched on and off by way of de-repression. Induction of �-Galactosidase Syrita Saul S12 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work