Biology of Microorganisms questions

1. Importance of microorganisms on our planet

a. When the first microbes appear on our planet and what metabolism they had?

Founded fossils suggest that first microbes appeared on our planet about 3.5 to 4 billion years ago and they were single-cell organisms. According to the RNA world hypothesis, all metabolic reactions and also replication was based on single RNA molecule.

b. When the first phototrophic microorganims appear and what type of photorophic metabolism they had?

The first phototrophic microorganisam appeared in the period between 3.4 billion years ago, and they had anoxygenic metabolism, using various molecules as electron donors. In the next era, 2450-2320 million years ago Cyanobacterium have been the first using oxygen for photosynthesis.

c. When the first eukaryotic mikroorganisms appear (describe the theories of their evolution)?

If we want to clasify something like Eukaryota, it had to have a membrane and organized genetic material. It is believed that inside space of eukaryotic cell was formed when one prokaryotic organism engulfed another, who then lived inside and contributed to the functioning of its host. The first proof of Eukaryota existing dates from 2,7 billion years ago.

2. Abiotic theory of origin of life (prof. Jack Szostak)

a. Describe the evolution of the first cells

On the Earth consist of hot water, reduced atmosphere and soil, chemical synthesis of more and more complicated polymers helped the formation of first â€˜'Protocell'', actually self-organized, self-ordered, a spherical collection of lipids. Decreasing entropy and â€˜'learn'' to form energy storage distinguished live of non-living matter.

b. What was the role of RNA, DNA, and proteins?

In the RNA world, self-replicating molecule and catalyst at the same time which could auto-create a copy numbers of itself was favored by Darwinian natural selection. By organizing compartments of first cells with storage of energy and regulated transport of material in space, evolution dictated forming of polymer which could be favorable for storing information- DNA. DNA was beneficial for many reasons for â€˜'taking over'' genetic information, one of the most important was the error rate of replication (more less with DNA). After forming of two molecules for storage of genetic information and replication, real proteins started to exist and were built from small peptides with all future roles in cells.

c. What role played clay minerals?

In 2002. It is confirmed that clay minerals added to the solution of fatty acids micelles sp sped up rate the vesicles formation to 100-fold and also they were the catalyst for RNA polymerization.

3. Taxonomy of microorganisms

a. Describe main taxonomic groups of microorganisms (describe the main domains of life)?

Today, accepted the classification of life is in three domains: Eukaryotes, Bacteria, and Archaea. Further classification of each domain is per se on Kingdom- Phylum- Class- Order- Family- Genus- Species.

b. What gen is the most suitable for phylogenetic studies and why?

The small subunit (SSU) of ribosome, 18S rRNA gene is the first and the most frequently used genes in phylogenetic studies because of small evolutionary rate and it is exposed to similar selective forces in all living beings.

4. What are the main characteristics of living organisms (list and describe them)?

There are:

-Forming and organization, defining the function of each part to decrease chaos- entropy.
-Metabolism, nutrition, growth, in a way to create energy for living and surviving.
-Adaptability and interaction, necessary to survive in open system with natural selection.
-Reproductivity, obligation to continue existing of own special.

5. Describe scientists who as the first constructed microscope

Antonie Philips van Leeuwenhoek was experimenting with glasses and lenses, constructed the first powerfull system to magnify the small drop water in which he recognizes microorganisms describe as animalcules.

6. Describe and explain Pasteur experiment.

He put two swan-necked flasks with nutrient broth. He sterilized them with fire, and after that, he broke the neck of one flask and left it open. In that one, over time microorganisms grew up from the particles of dust felt inside. In control one, with a long neck, dust particles couldn't travel.

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