Section A: Prokaryotes Types and Structure 1. What is microbiology?

Transcription

1 Section A: Prokaryotes Types and Structure 1. What is microbiology? 2. Compare and contrast characteristics of each bacterial type: Eubacteria and Archaebacteria. Eubacteria Both Archaebacteria 3. Label the structures on the bacteria diagram. plasmid, pilus, ribosomes, chromosome, flagellum, cytoplasm, capsule, cell wall, cell membrane 4. How are plasmids used in genetic engineering? 5. How have endospores allowed bacteria to survive during harsh environmental conditions? 6. Bacteria are often named based on cell shape and how the bacteria are arranged when growing. Describe what the following bacteria would look like based on this criteria. a. Streptococcus b. Staphylobacillus 1

2 Section B: Prokaryotic Adaptations 1. What methods do bacteria use to obtain nutrients? 2. What do we refer to bacteria who can t survive in the presence of oxygen? 3. Classification of bacteria can be based on cell wall composition. Identify which type of cell wall would result in a Gram positive bacterium or a Gram negative bacterium. A. B. 4. How did you determine if the bacteria was Gram (+) or (-)? 5. When performing a Gram stain test, what color would a bacterium with a cell wall like diagram A turn? 6. When performing a Gram stain test, what color would a bacterium with a cell wall like diagram B turn? 7. Explain how bacteria asexually reproduce. 8. List ways that bacteria can be used to benefit humans. I thought you might find this interesting. 2

3 9. The diagram illustrates the Kirby-Bauer (disk diffusion) test. The disks contain various antibiotics. Explain what is occurring in the diagram and how antibiotics work. 10. Explain what occurs in the phases of a bacterial life cycle. a. Lag Phase - b. Exponential Phase - c. Stationary Phase - d. Death Phase - Section C: Bacterial Plasmids A bacterial plasmid is a strand of DNA inside a bacterium which is independent of the bacterium's chromosomal DNA. Plasmids are capable of replicating on their own, and they can be passed between organisms, an important trait for bacteria, as they use plasmids to transfer genetic information between each other. The structure of a plasmid is often double-stranded and circular. It can contain a varying length of genetic information, and there are several different kinds of plasmids which can perform different functions. Some, for example, can perform conjugation, connecting with another bacterium to transfer genetic information. Others carry genetic information which confers antibiotic resistance, helps a bacterium break down nutrients to make them accessible, or makes the bacterium virulent. Gene transfer between bacteria via a bacterial plasmid is a fascinating technique which allows these organisms to transfer genetic material horizontally, rather than being limited to passing it between generations. This is one of the reasons bacteria have been able to thrive for so long, because they can adapt to their environments extremely quickly. Genetic researchers take advantage of the plasmid as an ideal vector for carrying DNA for research purposes. They use a conjugating plasmid which is designed to transfer genetic material, and insert the DNA of their choice into the plasmid so that it will be transferred. Then, they introduce the bacterial plasmid to a cell culture, allowing the cells to become infected, so to speak, with the new genetic material, which will then be reproduced when the cells divide. ( Plasmids in biotech delivering DNA Plasmids have been key to the development of molecular biotechnology. They act as delivery vehicles, or vectors, to introduce foreign DNA into bacteria. Using plasmids for DNA delivery began in the 1970s when DNA from other organisms was first cut and pasted into specific sites within the plasmid DNA. The modified plasmids were then reintroduced into bacteria. 3

4 Why plasmids are excellent DNA delivery vectors? Decades after their first use, plasmids are still crucial laboratory tools in biotechnology: Scientists can force bacteria to keep them. Virtually all plasmids that are used to deliver DNA contain genes for antibiotic resistance. Once bacteria have been treated with a plasmid, scientists grow them in the presence of antibiotic. Only those cells that contain the plasmid will survive, grow and reproduce. The others will be killed by the antibiotic. They are copied independently. Plasmids can be copied numerous times, regardless of whether the bacterial host is replicating its own DNA, and every time a plasmid vector is replicated, so is the introduced DNA that it contains. They are circular. DNA that is circular is well suited to incorporate extra DNA sequences. That s because it can be cut open without falling apart, then snap back together once new DNA has been incorporated. ( 1. What are plasmids? 2. Explain the structure of a plasmid and how they function. 3. What is a gene transfer? 4. How do genetic researchers use plasmids as vectors? 5. When did scientists first start using plasmids? 6. Why do scientists use plasmids as a vector to deliver DNA? 4

5 Section D: Viruses & Eukaryotes 1. Why are viruses considered nonliving? 2. Describe the structure of a virus. Include a drawing if necessary to help with your explanation. 3. How are viruses used in biotechnology? 4. Explain how viruses undergo the lytic cycle. Include a drawing if necessary to help with your explanation. 5. Explain how viruses undergo the lysogenic cycle. Include a drawing if necessary to help with your explanation. 6. What are the characteristics that most fungi share? 7. Explain how fungi perform external digestion. 8. Fungi are decomposers. What does this mean? 9. How are fungi used in biotechnology? 10. Describe the relationship between spores, hyphae and mycelium. 5

6 Section E: Cell Cultures 1. Explain how to prepare agar. 2. What is the advantage of using a liquid broth cell culture instead of a petri dish cell culture? 3. What factors can influence cell growth in labs? 4. What s the purpose of adding additives to media? 5. What is the most important part of media preparation? 6. At what temperature and how long do you heat media when prepping agar? 7. Why is growing mammalian cell cultures more difficult than bacterial cell cultures? 8. Where are the primary cells taken from when growing eukaryotic cell cultures? 9. What are cell lines? 10. How does contact inhibition influence eukaryotic cell growth? 11. What is used to transfer liquid cultures or move a colony? 12. How do you streak plates? 13. What are sterile techniques? List the key practices. 14. What must be included when labeling a petri dish? 15. RESEARCH use link on website: What is the difference between embryonic stem cells and adult stem cells? 6