Exam 2 Essay
Terrika Moore
“Question 10 Answer”
The Bergey’s Manual is a system used to classify procaryotes and bacteria. The first edition of the guide was based on specific characteristics of gram staining and metabolic reactions, which was a method called phenotypic. However with the new second edition, classifications and identification goes more in depth. It’s based on genetic information, specifies the relationship and phylogenetic history of the bacteria. Bergey’s Manual 2nd edition is broken down into five volumes: Vol. 1 separates Domain Archaea and Domain Bacteria into their own groups. Vol. 2 represents the Phylum Proteobacteria, breaks them into 5 classification groups. These bacteria all have gram negative cell walls. Vol. 3 represents Phylum Firmicutes, these are the low G + C gram positive bacteria which only has 3 classes. This group of bacteria includes staphylococcus and streptococcus. Vol. 4 includes a single class of Phylum Actinobacteria, in which this bacterium is a high G + C gram positive bacteria. Vol. 5 contains 9 Phyla in which they’re all gram negative but may or may not be related.
“Question 7 Answer”
Zygomycota are saprophytic molds in which this fungus receives it nourishments from dead or decaying matter. This fungus is the black mold on bread. Its asexual reproduction is sporangiospores and sexual spores are large zygospores and are enclosed by a thick wall. Zygomycota can cause serious infections in immunosuppressed or diabetic individuals. The specific disease “zygomyosis” is a disease in humans that may cause damage to the fetus if pregnant. Ascomycota nick named “sac fungi” because their spores are held by sac – like appendages. Their asexual spore is easily detached from its chain and become an airborne dust, and is the cause of the viral infection pneumonia in humans. Ascomycota obtains it’s nutrients from living or dead organisms. The yeast in Ascomycota is the same yeast used to make beer, wine and bread. Basidiomycota is also known as “club fungi” due to the club shape of sexual reproduction spore called basidium. This fungus is responsible for producing mushrooms. Basidiomycota carries the human pathogen of Crytococcus which causes serious respiratory illnesses. They obtain their nutrients from decaying dead organic matter also.
“Question 8 Answer”
Lichen is made up of both fungus and algae, together they produce the thallaus which is the body of the lichen. The thallaus forms when the fungal hyphae grows around the algal cells. Algae supplies food for the lichen through photosynthesis as well as they gain nutrients from plant growth. Fungus also obtains water and minerals for the lichen by protecting the algae. Although there’s a tight relationship between the three, Lichen is only one that has the capability to survive in areas algae or fungus could never survive alone. Lichen is found on roof tops, concrete walls/grounds and trees they’re also known to be one of the slowest growing organisms.
“Question 4 Answer”
DNA and RNA viruses are capable of causing cancer. When the genetics of a eukaryotic cell has been altered, this is where normal cells have the potential to become cancerous. Human Papillomavirus (HPV) which is a DNA virus that is capable of causing uterine, cervical and even anal cancers. Cervical cancer is the second leading cause of death in women today. Hence why it is very important to have routine pap smears, early detection of these precancerous cells can lead to treatment and possibly cure. Hepatitis C is a RNA virus that affects the liver, Hep. C can cause cirrhosis of the liver which than can lead to hepatocellular carcinoma (cancer of the liver). This cancer is more common in men than women.
“Question 3 Answer”
Viruses in animals are cultured using three different methods: living animal, embryonated eggs and/or cell cultures. In live animals they’re used to experiment the immune system response to viral infections. Embryonated eggs were the most inexpensive and convenient way to isolate and grow viruses for vaccines (such as influenza vaccines). Cell cultures have pushed embryonated eggs method to the back. This method is more convenient because the cells are all grown and cultured right in the lab. Due to differences between prokaryotic and eukaryotic cells in the multiplication (lytic cycle) of animal viruses, differ from phages when entering the host cell. There’s a four step process for multiplying: attachment, entry, uncoating and release. Plant viruses can cause deformed growth, wilting and even color change in their plant hosts. Plant cells have an impermeable cell wall that helps protect it from diseases; viruses may enter through fungi, wounds or insects that suck the plants sap. Infections can spread from one infected plant to another through its pollen. Plant viruses can multiply (lytic cycle) inside of insect cells.
“Question 2 Answer”
Viruses, Viroids, Prions and Bacteria all cause infectious diseases but all in their own distinctive way. Viruses are very tiny microorganisms that can only multiply in a living host. They also consist of a protein coat, a single type of nucleic acid (RNA/DNA) and have the ability to transfer viral nucleic acid to other cells. Although viruses and bacteria have their own identity they do share one small bacterium called rickettsia. Viroids are the cause of some plant diseases, viroids infections are the cause millions of dollars in crop damage annually. Prions are a proteinaceous infectious particle caused by a neurological disease in the brains of sheep/cattle, “Mad cow disease” falls into this category.
”Question 1 Answer”
1982 an American neurobiologist named Stanley Prusiner discovered that infectious proteins which were named “Prion” was the cause of the neurological disease in sheep. Viruses were discovered by the study of plant diseases; in 1935 Wendell Stanley isolated the infectious tobacco mosaic virus making it easier to purify a virus using chemical and structural studies. Viroids are RNA infections whose pathogens are only in plants and are responsible for diseases such as potato spindle tuber viroid.
Tortora, Gerard J., and Berdell R. Funke. : An Introduction. 11th ed. Boston: Pearson, 2013