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

Do the different dilutions of yeast cell suspension affect the number of yeast cells per cm3 that counted using haemocytometer under the microscope?

Extracts from this document...

Introduction

DCP & CE Title The effect of the different dilutions of yeast cell suspension on the number of yeast cells per cm3 that counted using haemocytometer under microscope. Aim To investigate the effect of the different dilutions of yeast cell suspension on the number of yeast cells per cm3 that counted using haemocytometer under microscope. Research Question Do the different dilutions of yeast cell suspension affect the number of yeast cells per cm3 that counted using haemocytometer under the microscope? Introduction ?The typical yeast cell is approximately equal in size to a human blood cell?[1]. It is so small and present in such huge number that it is hard to be counted. To verify accurately the number of yeast cells, a haemocytometer need to be used as it is the most suitable for counting microorganisms under the microscope. Haemocytometer has a grid that is etched into the glass. The grid is an arrangement of squares of different sizes that allows for an easy counting of cells. It is also carefully crafted so that the area bounded by the lines is known, and the depth of the chamber is also known. Thus, it is possible to determine the number of cells in a specified volume of fluid. Hypothesis As yeast cell suspension become more diluted, the number of yeast cells per cm3 that counted using haemocytometer under the microscope decrease. ...read more.

Middle

1. Loading the haemocytometer 1. The yeast cell suspension is gently shaken and well stirred to ensure the suspension is properly mixed. 2. The end of capillary tube is inserted into the suspension and risen the liquid into the tube. 3. The end of capillary tube is run along the edge of the cover slip between the arms of the ?H?. The area between the cover slip and the top half of the ?H? is filled with the suspension. 4. The slide is turned through 180O and repeated for the opposite edge of the cover slip. 5. The haemocytometer is placed on a damp tissue in a petri dish for at least two minutes to equilibrate. 1. Counting the cells 1. The haemocytometer is placed on the microscope stage. 2. The grid lines of the haemocytometer are focused using the 10X objective of the microscope. 3. The numbers of cells in the area of primary squares are counted using a hand tally counter. 4. The haemocytometer is moved to another primary squares and the counting is carried on until all 4 sets of primary squares are counted. 5. Steps 1-12 are repeated using each of the serial dilutions. 6. The number of yeast cells in the original yeast suspension into cells/cm3 is estimate. Quantitative Data Test tube Dilutions of yeast suspension Number of yeast cells per cm3 that counted using haemocytometer under microscope. ...read more.

Conclusion

Conclusion The number of yeast cells per cm3 that counted using haemocytometer under the microscope decrease when the yeast cell suspension becomes more diluted. This means that there is a larger proportion of water compared to yeast suspension, which explains why there are less yeast cells per cm3 in a diluted suspension. Thus the hypothesis is accepted. Evaluation Limitation and Weaknesses 1. The yeast cells did not spread equally in the central main grid of haemocytometer. Therefore, the result obtained is not precise and not reliable. 2. The process of counting the yeast cells under the microscope is not repeated. 3. The counting of yeast cells that touched the chosen two grid lines are not consistent in every observation. Some observation used the top and right grid lines while the other observations used the bottom and left grid lines. Suggestion 1. The yeast suspension must be stirred thoroughly before being dropped into the haemocytometer. This to ensure that the cells would spread equally and consistently in the haemocytometer. 2. The counting should be repeated at least three times to get certain yeast cells counted by calculating the average of the counting from each observation. 3. Only two grid lines should be considered as the area for counting the yeast cell. It is either top and right lines or bottom and left lines. ________________ [1] I S Dept (2006). What Is Yeast: http://www.dakotayeast.com/yeast_what.html, visited August 3, 2012. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Biology 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

See related essaysSee related essays

Related International Baccalaureate Biology essays

  1. The effect of the tempereature on yeast metabolism.

    Enzymes are sensitive to temperature changes up until a certain temperature and will increase in their activity up to this point. The reactions that take place in the enzymes will be quicker and so will create more of their products.

  2. Modelling Surface Area to Volume Ratio in Cells with Agar Cubes

    because of their different sizes and surface areas. As the cubes got bigger it took longer for the hydrochloric acid to diffuse completely through the cube. It took longer to reach the centre of the cube even though the rate of diffusion was the same for all the cubes.

  1. Stimuli and Response. Investigation Question: How do different tempos of music affect response ...

    5 (Movement 4) Made very stupid mistakes, shocked, a few scares, almost no focus, lost a lot of opportunities Piano Sonata No. 8 in C Minor (Allegro of Movement 1) Beginning was mellow, but later on the upbeat tempo made me lose focus and I was very accident prone Conclusion/Evaluation/Improvements:

  2. Research Question (RQ) How does the position of the arm (cuff) in relation ...

    These values were measured while the subject was still standing. * This method was repeated for each subject so that there were three trial values for each of the three positions of the arm.

  1. Biology Cell biology

    The time that it takes for the hydrolysis to fully complete the transferral conjunction with the temperature can be used to find the rate of reaction. From this is can be calculated at which temperature the enzyme amylase is most effective.

  2. How does changing the percentage of sucrose added to yeast affect the rate of ...

    Nevertheless yeast is a fungus, and thus like other living organisms it utilises enzymes to facilitate/catalyse and thus increase the rate of biological processes, without being used up themselves. In this case yeast contains the sucrase enzyme which catalysis the hydrolysis reaction of sucrose breaking it down into its constituent molecules glucose and fructose and thus respiration can take place.

  1. How does the salinity of water affect the germination of mung been seeds as ...

    Improvement The seeds were different colours and they also had different textures from wrinkled to smooth The different colour of the seeds indicate different ages, with the darker the seed indicating the older more dried out seeds. ?Seed age affected days to initial germination, six month old seeds germinated significantly

  2. Overview of Cells & Energy (Revision)

    nm: Virus 100 nm: Macromolecules 1 mm(micrometer): Bacteria 3 mm: Organelles 10 mm: Cell Surface area to volume ratio: *The rate of the metabolism of a cell is a function of its mass to volume ratio.* The more active a cell's metabolism, the more material must be exchanged if the cell is to continue to function.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work