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UW-Milwaukee BIOSCI 152 - Foundations of Biological Sciences

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BIO SCI 152 1st Edition Lecture 1Foundations of Biological Sciences II BioSci-152 Spring 2015Note regarding Exam on Microbiology (Saffarini) section of course: All exam questions will be multiple choice. Topics for exam questions will come from the lecture, or from the lecture notes, which will be posted on D2L. I will cover things in lecture that are not in the notes, so attendance in lecture is important. I will not ask questions about topics covered in the text (even the assigned reading) that I do not discuss in class. This applies only to the Microbiology (Saffarini) section of the course.I. Introduction: What is Microbiology?Microbiology- study of ‘microscopic’ organisms. (These are generally single celled organisms.)cellular microorganisms :1. Prokaryotes: no nucleusBacteriaArchaea2. Eukaryotes: membrane enclosed nucleusProtists (including algae)Fungiacellular microbes:VirusesMicroorganisms (or ‘Microbes’) are found in abundance in many environments but are often overlooked due to their small size. Examples shown in lecture include microbes present in the human mouth, in the intestinal tract of termites, and in the gut of tubeworms. They are also abundant in such seemingly unlikely places as antarctic sea ice, boiling hot springs, and deep within the earth’s bedrock. As you will see, microbes have dramatic effects on all environments on earth.Except for the last few centuries humans have been unaware of the existence of most microorgansisms. Microorganisms however have been aware of us, and some have learned how to interact with us, sometimes causing disease.Disease causing microbes (pathogens)Some microbes cause disease and have received much attention for this reason.These ‘pathogenic’ microbes influence human lives and history in dramatic ways, often determining the outcome of wars and the rise or decline of civilizationsFor example, the success of Europeans in their conquest of North and South America in the 1500s and 1600s had more to do with diseases such as measles and smallpox that were unintentionally carried by the Europeans than with military superiority.Diversity of MicroorganismsMicrobes which cause human disease constitute a very small fraction of the total microbial world.Microorganisms perform many important functions on our planet. Without them animals and plants could not exist.One example that we will discuss this semester is the ability of microbes to convert nitrogen gas (N2) to ammonia (NH4) which is needed by plants and animals. This processis called nitrogen fixation, and is only carried out by microorganisms.II. Phylogenetic tree of lifeAll known living organisms are thought to be descendents of the same primitive ancestorcell, with evolution giving rise to the tremendous diversity present today. Phylogenetic trees depict the relationships of organisms to each other. Often molecular sequence information is used to determine these relationships. For example, ribosomal RNA sequences (rRNA) are used for this purpose, since all organisms have rRNAs.Analysis of phylogenetic trees reveals that there are three large groups of organisms, known as 'Domains'': the Archaea, The Bacteria, and The Eukarya (eukaryotes).The Bacteria and Archaea are prokaryotes and are microorganismsMany but not all of the Eukarya are also microorganismsExamination of the phylogenetic tree also reveals that microorganisms dominate the tree. Two of the three domains (Archaea and Bacteria) contain only microorganisms, as do many of the major branches of the third domain (Eukarya).Naming organisms:Genus species (general specific)Bacillus anthracis: this bacterium was named after shape (rod or ‘bacillus’), and disease (anthrax).There are many other members of the genus Bacillus also, such as Bacillus subtilis.III. History of life on earthMicrobes have inhabited Earth for much of its existence (contrast with animals and plants)Earth is about 4.6 Billion years old (Billion = one thousand x million years) Timeline: (Billions of years)0 earth formedliquid water present 0.8-1.1 origin of life on earth (prokaryotic)1.7-2.1 cyanobacteria begin to produce O2 atmosphere (and ozone layer) 2.4-2.8 origin of eukaryotesorigin of multicellular organisms (animals, plants, fungi)age of dinosaurs 4.599 humans appear (100,000 years, or 0.0001 billion years ago)Today Microbes will also almost certainly remain on earth long after animals and plants have disappeared. Scientists believe that within the next billion years the sun will become hotter and earth will be too warm to support plants and animals. Microbes are expected to continue on earth for billions of years beyond this point.IV Summary of Important Areas of MicrobiologyMedical microbiology- Study of microbes that cause disease in humans or animals Environmental Microbiology- Interaction of microbes with the environment. Also includes importance of microbes to agriculture (such as nitrogen fixation) to production of fuels such as ethanol and methane, and to degradation of waste chemicals (bioremediation). Food Microbiology- use of microbes in food production (beer, cheese, bread, sausages, pickles, chocolate, etc.) microbes and food safety Biotechnology- use of microbes to make specific products, often involving genetic engineering. Examples- antibiotics, insulin 5. Microbes as model organisms- Microbes have simple cells and simple genomes. Study of microbes helps us understand more complex organisms.Example- Studies of bacterial (E. coli) DNA repair mechanisms led directly to discovery of human genes involved in cancer.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a


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