BIO 191 CH 24 HW

Classify each statement or picture as applying to gram-positive bacteria, gram-negative bacteria, or both. Drag each item to the appropriate bin.

Label the diagram below to show the relationship between nutritional modes of bacteria. Drag the labels to their appropriate locations on the diagram.

Azotobacter is a genus of bacteria that live in soil and have the following characteristics: They are bacilli. They are gram-negative. They are obligate aerobes. They can fix nitrogen. (Unlike some other nitrogen-fixing bacteria, which associate with the roots of plants, Azotobacter species are free-living.) Select the four statements that are true for bacteria in the genus Azotobacter. -They appear purple after Gram staining. -They use O2 for cellular respiration. -They require amino acids or other organic molecules as a source of nitrogen. -They are poisoned by O2. -They can carry out anaerobic respiration in an environment that lacks O2. -They have a relatively thin layer of peptidoglycan in their cell wall. -They can convert atmospheric nitrogen to ammonia. -They have the appearance of coils or corkscrews. -They are shaped like rods.

The prokaryotic cells that built stromatolites are classified as _____. proteobacteria chlamydias spirochetes gram-positive bacteria cyanobacteria

The prokaryotic cells that were the first to add significant quantities of oxygen to Earth's atmosphere are classified as _____. proteobacteria chlamydias spirochetes gram-positive bacteria cyanobacteria

Streptococcus pyogenes is classified with _____. proteobacteria chlamydias spirochetes gram-positive bacteria cyanobacteria

Organisms that can cause nongonococcal urethritis are classified with _____. proteobacteria chlamydias spirochetes gram-positive bacteria cyanobacteria

The chemoheterotroph Proteus vulgaris is a rod-shaped bacterium classified with _____. proteobacteria chlamydias spirochetes gram-positive bacteria cyanobacteria

Spiral-shaped bacteria are likely to be placed with _____ proteobacteria chlamydias spirochetes gram-positive bacteria cyanobacteria

According to this phylogenetic tree, which of these pairs of prokaryotic subgroups share the most recent common ancestor? Euryarchaeota ... Cyanobacteria Proteobacteria ... Crenarchaeota Proteobacteria ... Euryarchaeota Euryarchaeota ... Crenarchaeota Crenarchaeota ... Cyanobacteria

What hypothesis were the researchers testing in this study? Sugar beet seedlings have a higher rate of fungal infection in heated soils. Soils can be treated to reduce their ability to suppress fungal disease in seedlings. The disease-suppressive properties of soils are due to the activities of soil microorganisms. Sugar beet seedlings have a lower rate of fungal infection in disease-suppressive soils.

What is the independent variable in this study? soil treatment percentage of seedlings with fungal disease number of seeds in each soil treatment

What is the dependent variable in this study? soil temperature percentage of seedlings with fungal disease number of seeds in each soil treatment

What is the total number of pots used in this experiment, and how many plants received each soil treatment? 4 pots total, 5 plants per treatment 4 pots total, 8 plants per treatment 20 pots total, 32 plants per treatment 32 pots total, 20 plants per treatment

Identify a controlled variable from the experiment. the amount of light the plants were exposed to the number of plants per treatment percentage of seedlings with fungal disease the amount of disease-suppressive soil the plants were grown in

How do the results shown in Figure 2 support this conclusion? Fungal infection rate increased in seedlings grown in disease-suppressive soil that had been heated. A high rate of fungal infection was found in seedlings grown in soil from the margin of the field. Fungal infection rate decreased in seedlings grown in soil from the margin of the field mixed with disease-suppressive soil. The lowest rate of fungal infection was found in seedlings grown in disease-suppressive soil.

Which of the following results would have disproved the hypothesis that microorganisms are responsible for the disease-suppressive properties of soils? if seedlings had similar fungal infection rates when grown in 100% and 10% disease-suppressive soil if seedlings had similar fungal infection rates when grown in heated and unheated disease-suppressive soil if seedlings had similar fungal infection rates when grown in disease-suppressive soil and soil from the margin of the field No results could have disproved the hypothesis that microorganisms are responsible for the disease-suppressive properties of soil.

In one experiment, scientists raised mice in germ-free conditions so the mice lacked intestinal microbes. The mice were fed a low-fat diet rich in the complex plant polysaccharides, such as cellulose, that are often called fiber. When the mice were 12 weeks old, the scientists transplanted the microbial community from the intestine of a single "donor" mouse into all of the germ-free mice. Then they divided the mice randomly into two groups and fed each group a different diet. Group 1 (the control group) continued to eat a low-fat, high-fiber diet. Group 2 (the experimental group) ate a high-fat, high-sugar diet. Identify the components of this experiment by dragging the labels into the appropriate bins.

After 8 weeks on the different diets, the scientists collected the following data on the two groups of mice: the amount of weight gained the amount of body fat the composition of the microbial community, especially the abundance of the two types of bacteria that dominate this region of the intestine -- Firmicutes and Bacteriodetes The results are shown in this data table. Group Weight gain Body fat (% of total body weight) Relative abundance of Firmicutes in intestine Relative abundance of Bacteriodetes in intestine Group 1 (control) Low-fat, high-fiber diet 1.5 grams 1.7% 75% 20% Group 2 (experimental) High-fat, high-sugar diet 5.3 grams 3.7% 97% 3% Which three statements are valid conclusions that can be drawn from these results? -People who consume a high-fat, high-sugar diet will have increased body fat. -A high-fat, high-sugar diet alters the composition of the microbial community. -A relative abundance of Bacteriodetes less than 25% results in obesity. -A high-fat diet is more likely to cause obesity than a high-sugar diet. -A microbial community dominated by -Firmicutes is associated with increased body fat. -Firmicutes cause obesity. -A high-fat, high-sugar diet results in greater weight gain than a low-fat, high-fiber diet.

Is the microbial community in the intestine a key to understanding obesity? To explore this question, scientists conducted another experiment. The scientists hypothesized that the microbial community of obese mice is more efficient at extracting energy from food, thus providing more calories to the host, and that it promotes more fat deposition than does the microbial community of lean mice. They decided to test this hypothesis by transplanting microbes from an obese donor mouse into lean mice. For this experiment, the scientists randomly divided lean germ-free mice into two groups. The experimental group received microbes from a genetically obese donor (the donor's obesity was due to genetic factors, not diet). The control group received microbes from a genetically lean donor. Both groups were fed the same low-fat, high-fiber diet. After two weeks, the scientists measured the increase in body fat in the mice. They also determined the amount of energy (in kcal/g) in the feces of both groups -- that is, the energy in the food molecules that was not extracted or absorbed by the mice. What experimental results would support the scientists' hypothesis? Label the bars on the graphs to match the results predicted by the hypothesis.