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Biology Study Guide
Module 2
Question | Answer |
---|---|
1a. Pathogen | 1a. An organism that causes disease. |
1b. Saprophyte | 1b. An organism that feeds on dead matter. |
1c. Parasite | 1c. An organism that feeds on a living host. |
1d. Aerobic organism | 1d. An organism that requires oxygen. |
1e. Anaerobic organism | 1e. An organism that does not require oxygen. |
1f. Steady state | 1f. A state in which members of a population die as quickly as new members are born. |
1g. Exponential growth | 1g. Population growth that is unhindered because of the abundance of resources for an ever-increasing population. |
1h. Logistic growth | 1h. Population growth that is controlled by limited resources. |
1i. Conjugation | 1i. A temporary union of two organisms for the purpose of deoxyribonucleic acid (DNA) transfer. |
1j. Plasmid | 1j. A small, circular section of extra DNA that confers one or more traits to a bacterium and can be reproduced separately from the main bacterial genetic code. |
1k. Transformation | 1k. The transfer of a DNA segment from a nonfunctional donor cell to that of a functional recipient cell. |
1l. Transduction | 1l. The process in which infection by a virus results in DNA being transferred from one bacterium to another. |
1m. Endospore | 1m. The DNA and other essential parts of a bacterium coated with several hard layers. |
1n. Strains | 1n. Organisms from the same species that have markedly different traits. |
2. Label all of the indicated structures on the bacterium on page #65&38. | a.Plasma membrane b.Flagellum c.Capsule d.Deoxyribonucleic acid e.Cytoplasm f.Cell wall g.Fimbria h.Ribosome |
3. Describe the functions of each of the components labeled in problem #2. | a.Plasma membrane-Wall of chemicals which regulate what the bacterium takes in from the outside world. b.Flagellum-Used for locomotion. c.Capsule-Adheres bacterium to surfaces. d.DNA-Contains all required information for life of the bacterium. |
3. (continued) | e.Cytoplasm-Semifluid substance that supports the DNA and ribosomes. f.Cell wall-Holds the contents of the bacterium together. g.Fimbria-Fibrous bristles used for grasping. h.Ribosome-Makes proteins |
4. What is the most popular means by which bacteria obtain food? | Feeding on dead matter. |
5. If a bacterium is parasitic, is it heterotrophic or autotrophic? | Heterotrophic because it feeds on a living host. |
6. List the basic steps in asexual reproduction (more specifically binary fission) among bacteria. | A. DNA loop is attached to a point on the plasma membrane. B. The DNA is then copied. C. Cell wall elongates, separating the two strands of DNA. D. New cell wall material and plasma membrane begin to grow, closing the two strands off from each other. |
6. (continued) | E. When the cell wall and plasma membrane growth is complete, two bacteria (a parent and an offspring) exist where there was once just one. As long as no mutation took place, the two bacteria are identical. |
7. A sample of food is dehydrated, which kills all of the bacteria. Then bacteria-free water is added to the food in a bacteria-free environment. Nevertheless, microscopic investigations indicate that bacteria are in the food. How did they get there? | Several of the bacteria formed endospores, which, although the bacteria died, they reformed because the endospore survived. |
8. What kind of growth does a population of bacteria experience when just a few of them are placed in an environment rich with resources? | Exponential growth. |
9. A population of bacteria experiences logistic growth. What can you say about the resources of their environment? | The resources are limited. |
10. Even though genetic recombination among bacteria does not result in offspring, it can significantly affect the growth of the population. Why? | Because DNA can be transfered, resulting in genetic information being donated that could be useful to the recipient, therefore possibly expanding the recipient's life. |
11. What are the technical names of the three common bacterial shapes? | Coccus (spherical), bacillus (rod-shaped), and spirillem (helical). |
12. A bacterium is heterotrophic and Gram-negative. To what phylum and class does it belong? | Phylum Gracilicutes and class Scotobacteria. |
13. A spirillum bacterium is Gram-positive. To what phylum and class does it belong? | Phylum Firmicutes and class Thallobacteria. |
14. A bacterium has no cell wall. To what phylum and class does it belong? | Phylum Tenericutes and class Mollicutes. |
15. A bacterium lives in boiling-hot water. To what phylum and class does it most likely belong? | Phylum Mendosicutes and class Archaebacteria. |
16. In the six-kingdom classification system, what replaces kingdom Monera? | Kingdoms Archaebacteria and Eubacteria. |
17. What conditions are ideal for most bacteria to grow and reproduce? | Moisture, moderate temperature, nutrition, darkness and oxygen. |
18. What methods exist for reducing the chance of bacterial contamination of food? | Exposing the food to extreme heat or radiation, freezing the food, and dehydration. |