Cell Communication

The purpose of this experiment was to calculate the percentage of yeast at each stage before and after a night of incubation.

This experiment is observing cell communication in yeast cells. Yeast cells are unicellular fungi that can reproduce sexually and asexually. For a yeast cell to reproduce sexually, the change their body shape into a gamete called a shmoo. When the a-type and alpha-type schmoo fuse together, the two nucleus’s to form  diploid nucleus with an a/alpha- genome. From there a zygote forms which then begins to divide into daughter cells. Yeast do require a time of incubation before they begin to divide, but once they begin to divide they continue at rapid rates until the area gets too populated, then the death phase takes over.

First we obtained agar plates and culture tubes in which we would grow and store the yeast. We labeled them alpha-type, a-type and mixed. We then scraped a small amount of each type of yeast, placed 2mL of sterile water onto a microscope slide then looked at each slide carefully. We observed and recorded approximately how many yeast cells we saw. After we were finished with that, we gave the yeast in the culture tubes some broth to last them overnight, then placed them in the incubator. The next morning we repeated the same procedure. We observed and recorded how many more yeast cells there were due to the yeast cells mating overnight. 

The amount of yeast increased because yeast reproduces asexually.  This means that it is able to reproduce without the help of a partner.  When yeast reproduces, it creates shmoos.  When shmoos of different yeasts touch, they combine creating more yeast. However, in order for them to touch they have a sort of attraction that pulls them together.  In the end, the amount of yeast  created was more than 10 times as great after a twenty four hour period.  When we first peered into the microscope, before the twenty four hour time had elapsed, we noticed that the mixed yeast already had connected with other cells more often than the isolated a or alpha types.  Some of the mixed had already connected with five other shmoos.

From our experiment we can conclude that reproduction of yeast cells can occur after spending a night in an incubator. Yeast cells are able to communicate with each other as long as there is fuel for the cells. Cell communication can happen within a cell or between two cells, this is represented by the ability of yeast to reproduce. We could have run into some errors in regards to which yeast cells are which as we forgot to label some of the pictures.

Mixed type yeast before twenty four hours had passed

a-type yeast before twenty four hours had passed

Alpha type yeast after twenty four hours had passed