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Biology 11 Name: ______________________ Blk: ________Date:__________ Bacteria Worksheet Complete the following based on the type of biological classification: Traditional five-kingdom system: 1. Monera 2. Protista 3. Fungi 4. Plantae 5. Animalia Six kingdom system: 1. Eubacteria 2. Archaebacteria 3. Protista 4. Fungi 5. Plantae 6. Animalia Three-domain system: 1. Bacteria 2. Archaea 3. Eukarya The three basic shapes of bacteria are 1. Rod Shaped, which are called bacilli 2. Spherical shaped, which are called Cocci 3. Spiral Shaped, which are called Spirilla Growth patterns: The prefix which indicates that bacteria are growing in chains is Strepto. The prefix which indicated that bacteria grow in pairs is Diplo. The prefix which indicates that bacteria grow in clumps is Staphylo. Cell wall: What is the structural difference between gram-negative and gram-positive bacteria? Gram Positive: Bacterial walls have one layer of carbohydrate and protein molecules (takes up crystal violet) Gram Negative: bacterial cells have two layers of protein and carbohydrate molecules (take up safranine) Gram-negative bacteria take up the Safranine dye and turn the color Pink. Gram-positive bacteria take up the Crystal Violet dye and turn the color Purple. Obtaining Energy 1. Autotrophs make food from inorganic molecules. Name and describe how the two types of these bacteria obtain energy: Biology 11 Name: ______________________ Blk: ________Date:__________ A. Phototrophic Autotrophs: use carbon dioxide as sole carbon source and light as it’s sole source of energy Example: cyanobacteria and some photosynthetic eubacteria B. Chemotrophic Autotrophs: Obtain energy from breaking down inorganic molecules (i.e hydrogen sulphide, nitrates, sulfur and iron) Example: nitrosomonas 2. Heterotrophs obtain energy and carbon from an organic source. Name and describe how the two types of these bacteria obtain energy: A. Phototrophic Heterotrophs: Photosynthesis for energy and require organics for nutrition Example: Green or purple bacteria B. Chemotrophic Heterotrophs: Breaks down organic molecules to obtain energy (most bacteria and most animals) Example: Most bacteria and animals Bacterial Respiration Respiration is the process that releases energy by using oxygen to break down food molecules. Fermentation is the process that produces energy without oxygen. Observe the three test tubes below: There is a different type of bacteria in each test tube. Determine whether each type of bacteria is an obligate aerobe, obligate anaerobe or a facultative anaerobe, and then explain how you came to this conclusion. Test tube #1: Obligate Aerobe Explanation: It can be observed that all the bacteria are clustered around the top of the test tube. This is most likely because they are trying to position themselves near to the source of oxygen in the test tube. The bacteria in test tube 1 are dependant on oxygen to survive and are therefore obligate aerobes. Test tube #2: Obligate Anaerobe Explanation: The bacteria in test tube 2 are all clustered around the bottom of the test tube. They are most likely trying to position themselves as far away from the source of oxygen as possible and are therefore obligate anaerobes (can only survive in the absence of oxygen. Test tube #3: Facultative Anaerobe Explanation: The bacteria in test tube 3 are spread throughout the test tube with a few clustered towards the top of the tube. Because the bacteria are able to survive throughout the test tube (near and far away from the source of oxygen) they are most likely Facultative Anaerobes because they can survive with and without the presence of oxygen. Biology 11 Name: ______________________ Blk: ________Date:__________ Bacterial Growth and Reproduction Most often, bacteria reproduce by simple cell division called binary fission. This is a form of asexual reproduction in which two identical daughter cells are formed Bacteria can exchange genetic information through the process of conjugation. Two bacterial cells are connected by a long bridge of protein. The genetic information of the donor cell is then transferred to the other cell called the recipient cell. Certain types of bacteria can survive harsh environmental conditions by developing endospores. Label the diagram of a typical bacterium using the following terms 1. 2. 3. 4. 5. 6. 7. 8. Cell membrane Capsule (outer membrane) Cell wall Flagella Genetic material Ribosome Pili Cytoplasm Now answer the following questions: 1. Is the bacterium in the diagram a bacillus, coccus or spirillium? Explain. Bacillus, the shape of the bacterium is in the shape of a rod. Coccus would be a sphere, and spirillium would be in a spiral shape. 2. How would you expect this bacterium to move? By using it’s flagella to propel it’s body. 3. Suppose that this bacterium was a streptobacillus. What kind of colonies would you expect it to form? The colonies would form in chains. 4. This bacterium is gram-negative. What happens when it is subjected to gram staining? The bacterium would take up the safranine dye and turn the color pink. 5. The bacterium is facultative anaerobe. What process or processes would you expect it to use to break down food? Explain. The bacterium could use either respiration or fermentation to break down food because it is a facultative anaerobe. In the presence of oxygen the bacterium would use respiration to breakdown food and release energy. When there is no oxygen available the bacterium would use fermentation to produce their energy. Biology 11 Name: ______________________ Blk: ________Date:__________ Helpful Bacteria Many bacteria are saprophytes. Saprophytes release digestive enzymes into the organic material around them (e.g. cellulose from trees) and break down the material into nutrient molecules that the bacteria or other organisms can absorb. This process causes the organic material to decay. Explain what would happen without the presence of saprophytes: Decay is a vital link in all nutrient cycles. Without it, the matter from once-living organisms would accumulate and stop the biosphere from functioning normally. Food chains would be broken—producers would not have nutrients to grow; and without producers, consumers would have nothing to eat. Describe and explain two ways bacteria play a helpful role in our environment (Use the table and the library/internet to support your answers) 1. Bioremediation: using bacteria to treat polluted sites Example: A toxic wood preservative called penta-chlorophenol has been known to seep from storage containers, contaminating nearby soil and underground water. The cost of cleaning the soil by the traditional means of excavating and burning contaminants ranges from $200 to $300 per cubic metre. In some cases, hundreds of tonnes of soil must be excavated. A bacterium from the genus Flavobacterium is a dramatically more economical and efficient alternative to these traditional methods of detoxification. The toxic compound is actually a nutrient for the bacterium. The bacteria require only oxygen and nutrients found in the soil. The treatment is also inexpensive:$30 to $50 per cubic metre of soil. Besides its low cost, another advantage is that the bacterial population grows as long as the toxic molecules remain; once the chemical has been broken down, they die. 2. Bacteria as Pro-biotic agents Researchers are discovering that many lesser-known bacteria, grouped as probiotics (literally,“for life”), help maintain health and may have the potential to prevent disease. Although they consist mainly of lactic acid bacteria, bifidobacteria (Y-shaped,found in the human intestine) and yeasts have also been used successfully. In the future, look for these organisms to be included in foods or food additives, or used in the treatment of ear, intestinal, and urinary-tract infections; the reduction of blood cholesterol levels; and the prevention of infections, tooth decay, and perhaps some cancers. Biology 11 Name: ______________________ Blk: ________Date:__________ 3. Bacteria in Industry During metabolism, bacteria make enzymes that are useful in many industrial processes. Industrial fermenters (Figure 2) are used to harvest enzymes, which, in turn, are used to produce consumer products. Examples are summarized in Table 1. Even though enzymes can be used, they are costly. Usually, intact bacteria are used because they are less expensive. Harmful Bacteria There are hundreds of strains of E.coli bacteria; the combination of numbers and letters in the name of the bacterium refers to the specific markers found on the bacterium’s surface. Whereas most live harmlessly in the intestines of healthy animals, E.coli O157:H7 produces a dangerous poison or toxin. The major source of E.coli O157:H7 infections is undercooked ground beef, since fecal matter can contaminate beef as the meat is processed. E.coli O157:H7 is found in the intestines of cattle; when the cattle are killed, the bacteria can become mixed into beef when it is ground. Other sources of E.coli include processed meats, sprouts and leafy green produce, unpasteurized milk and juice, and contact with cattle. Drinking inadequately chlorinated water or swimming in contaminated lakes or pools may also expose people to this deadly strain. The organism is easily transmitted from person to person. Day-care or long-term-care centers, cattle barns, and petting zoos are prime areas of concern. Explain 2 methods for preventing the transmission of E.coli (use the library or internet to research practical answers) 1. Thoroughly cooking ground beef and meat. 2. Only drink water that has been properly chlorinated (especially when camping etc. ) 3. Avoid ingesting water when swimming in contaminated lakes or pools. 4. Don’t eat food when in cattle barns or petting zoos. 5. Properly wash and disinfect food containers and serving utensils (hot water, soaps)