Bacteria and Archaea Study Guide PDF

\# Study Guide: Chapter 27 - Bacteria and Archaea \#\# Overview This study guide is based on Chapter 27 of Campbell Biology, focusing on the characteristics, structure, function, reproduction, and ecological roles of prokaryotes, specifically bacteria and archaea. \-\-- \#\# Key Concepts \#\#\#...

\# Study Guide: Chapter 27 - Bacteria and Archaea \#\# Overview This study guide is based on Chapter 27 of Campbell Biology, focusing on the characteristics, structure, function, reproduction, and ecological roles of prokaryotes, specifically bacteria and archaea. \-\-- \#\# Key Concepts \#\#\# 1. Characteristics of Prokaryotes \- \*\*Definition\*\*: Prokaryotes are single-celled organisms that make up the domains Bacteria and Archaea. \- \*\*Abundance\*\*: They are the most abundant organisms on Earth and can thrive in diverse and extreme environments due to several characteristics: \- \*\*Small size\*\*: Generally 0.5--5 μm, much smaller than eukaryotic cells. \- \*\*Rapid reproduction\*\*: They can reproduce quickly through binary fission. \- \*\*Diverse adaptations\*\*: Ability to adapt to various environments. \- \*\*Mutations\*\*: Rapid mutation rates contribute to genetic diversity. \- \*\*Endospores\*\*: Resistant cells that survive harsh environments. \#\#\# 2. Prokaryotic Structure \- \*\*Cell Shapes\*\*: \- Cocci (spherical) \- Bacilli (rod-shaped) \- Spirilla (spiral-shaped) \- \*\*Cell Surface Structures\*\*: \- \*\*Capsules\*\*: Sticky layers of polysaccharide or protein that help in adherence, prevent dehydration, and protect against immune responses. \- \*\*Flagella\*\*: Structures used for movement; differ in structure from eukaryotic flagella. \- \*\*Cell Wall\*\*: \- Composed mainly of peptidoglycan in bacteria. \- Helps maintain cell shape and protects against lysis. \- Archaea have cell walls lacking peptidoglycan. \#\#\# 3. Gram Staining \- \*\*Gram-positive\*\*: Thick peptidoglycan layer; stains purple and is susceptible to penicillin. \- \*\*Gram-negative\*\*: Thin peptidoglycan layer with an outer membrane; stains pink and is resistant to penicillin. \#\#\# 4. Genetic Diversity \- \*\*Reproduction\*\*: Prokaryotes reproduce quickly through binary fission. \- \*\*Genetic Recombination\*\*: \- \*\*Transformation\*\*: Uptake of foreign DNA. \- \*\*Conjugation\*\*: Transfer of DNA between prokaryotes through direct contact. \- \*\*Horizontal Gene Transfer\*\*: Movement of genes between species. \#\#\# 5. Metabolism \- \*\*Nutritional Diversity\*\*: \- Prokaryotes have diverse metabolic pathways, classified as: \- \*\*Photoautotrophs\*\* \- \*\*Chemoautotrophs\*\* \- \*\*Photoheterotrophs\*\* \- \*\*Chemoheterotrophs\*\* \- \*\*Oxygen Metabolism\*\*: \- \*\*Obligate aerobes\*\*: Require oxygen. \- \*\*Obligate anaerobes\*\*: Poisoned by oxygen. \- \*\*Facultative anaerobes\*\*: Can use oxygen or undergo fermentation. \#\#\# 6. Nitrogen Metabolism \- \*\*Nitrogen Fixation\*\*: Some prokaryotes, such as diazotrophs, can convert N2 to NH3, which is essential for plants. \#\#\# 7. Biofilms \- \*\*Definition\*\*: Surface-coating colonies formed by prokaryotic species. \- \*\*Function\*\*: Facilitate nutrient exchange and waste removal; involved in evading host defenses. \#\#\# 8. Ecological Roles \- Prokaryotes play crucial roles in biosphere: \- \*\*Decomposers\*\*: Recycling nutrients in ecosystems. \- \*\*Symbiotic Relationships\*\*: \- \*\*Mutualism\*\*: Both organisms benefit. \- \*\*Commensalism\*\*: One benefits, the other is unaffected. \- \*\*Parasitism\*\*: One benefits at the expense of the other. \#\#\# 9. Impacts on Humans \- \*\*Pathogenic Bacteria\*\*: Cause diseases such as cholera, pneumonia, and tuberculosis. \- \*\*Antibiotic Resistance\*\*: Resistance spread via rapid reproduction and horizontal gene transfer. \- \*\*Bioremediation\*\*: Use of bacteria to clean pollutants (e.g., oil spills). \#\#\# 10. Classification of Prokaryotes \- \*\*Major Groups\*\*: \- \*\*Proteobacteria\*\* \- \*\*Cyanobacteria\*\*: Photosynthetic; contributed to the oxygenation of the atmosphere. \- \*\*Gram-positive bacteria\*\*: Include soil decomposers and pathogens. \- \*\*Archaea\*\*: Extremophiles, such as halophiles and thermophiles. \-\-- \#\# Review Questions 1\. What are the main structural characteristics that enable prokaryotes to thrive in various environments? 2\. How does the Gram stain differentiate between types of bacteria? 3\. Describe how prokaryotes reproduce and how this contributes to genetic diversity. 4\. Explain the roles of prokaryotes in ecosystems and their importance to human health. 5\. Discuss the mechanisms of antibiotic resistance in bacteria. \-\-- \#\# Important Figures \- \*\*Figure 27.1A\*\*: Overview of prokaryotic characteristics. \- \*\*Figure 27.7\*\*: Structure of bacterial flagella. \- \*\*Figure 27.3\*\*: Comparison of gram-positive and gram-negative bacteria. \- \*\*Figure 27.12\*\*: Illustration of conjugation in bacteria. \-\-- \#\# Conclusion Understanding the characteristics, adaptations, and ecological roles of bacteria and archaea is crucial for grasping their importance in both environmental and health contexts. Use this study guide to review the key concepts and ensure a comprehensive understanding for your test.