Term paper: In this assignment you will learn about one kind of organism in some

Question

Term paper:

In this assignment you will learn about one kind of organism in some detail. for this assignment you need to write a paper about one species living organism. you may choose any wild species, (not humans or a domestic plant or animal). do some research on the organism. need to look through 4 sources.

report must include:

1. 900 words paper

2. the common and scientific name of the species.

3. where in the world it occurts, its distribution and habitat.

4. what it looks like.

5. any human uses of the species.

6. any conservation concerns about the organism, is it threatened with extinction

7. interesting information about it.

8. the list of the references you uses in learning about this organism.

Explanation / Answer

Sacchromyces cerevicease

Sacchromyces cereviceae is commonly known as the baker's yeast. Very few organisms have played such a large part in the understanding of modern day genetics as S.cereviceae. It is unicellular, eukaryotic organism found in a diverse range of environmental conditions all over the globe.S. cerevisiae is an attractive model organism due to the fact that its genome has been sequenced, its genetics are easily manipulated, and it is very easy to maintain in the lab. Because many yeast proteins are similar in sequence and function to those found in other organisms, studies performed in yeast can help us to determine how a particular gene or protein functions in higher eukaryotes (including humans).

History of Yeast:
Unlike higher eukaryote model organisms, yeast had to be established as living organisms before they could be used as a model organism. Early in the nineteenth century, the existence of living microbes was a matter of debate. By studying yeast as the cause of fermentation, scientists recognized them as microorganisms and began to characterize them.S. cerevisiae was first established as a tool for genetic studies in the 1930's and 40's - nearly 100 years after Mendel performed the first controlled genetic experiments on pea plants. By the end of the 20th century, S. cerevisiae was (and still is!) widely accepted as one of the most powerful model systems for the study of genetics and biochemistry.

Use of Yeast in genetics

One of the greatest advances in yeast genetics occurred in 1996 when a global consortium finished sequencing the genome of S. cerevisiae (the first eukaryotic genome to be completed!). The results of this sequencing effort revealed that the 16 chromosomes of S. cerevisiae harbor about 6,200 potential protein-encoding genes (also known as open reading frames, or ORF's), nearly 40% of which have obvious homologues in other eukaryotic organisms. At that time, less than half of the yeast ORF's identified were being studied, and even today, hundreds remain poorly characterized or have no known function.In addition to providing a detailed genetic map, this sequencing triumph helped usher in the era of genomics. Instead of being limited to the study of one or a few genes, researchers developed techniques to study changes in the expression levels of thousands of genes simultaneously.

Means for Classification: Saccharomyces cerevisiae is in the fungi kingdom. The reasons for this classification are because it has a cell wall made of chitin, it has no peptiodglycan in its cell walls, and its lipids are ester linked. It also uses DNA template for protein synthesis and it has larger ribosomes. It is then consider a yeast because it is a unicellular organism so it can not form a fruiting body; like other fungi.

Adaptations: Saccharomyces cerevisiae has adapted in several important ways. One is the fact that they are able break down their food through both aerobic respiration and anaerobic fermentation. They can survive in an oxygen deficient environment for a period. Another adaptation they have is their ability to have both sexual and asexual reproduction. Very few other Ascomycota can do both processes. And very few organisms can do all four of these processes. This allows this species to live in many different environments.

Nutrition: Saccharomyces cerevisiae gets its energy from glucose.

Life Cycle: Saccharomyces cerevisiae has both asexual and sexual reproduction.In asexual reproduction the haploid of the yeast under goes mitosis and forms more haploid yeasts. There is an a and strain of these haploids. Then these haploid yeasts, one from each strain, can fuse together and become on cell. Then the nuclei of both cell fuses together and this cell is now the zygote. These diploid cells can go through mitosis, which they call budding, and four more zygotes or they can under go meiosis and from an ascus which will split into four ascospores. These haploids can then under go germination and become haploid yeast again.

References:
1. Madigan, Michael T., and John M. Martinko. Biology of Microorganisms. 11th ed. Vol. 1. Upple Saddle River, NJ: Pearson Education, 2006.
2. http://www.benchfly.com/blog/saccharomyces-cerevisiae-a-k-a-budding-bakers-brewers-yeast/
3. http://faculty.bsc.edu/phanson/yen/basics.html

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