In this chapter, the following topics are important for long questions in board exams:

1. Structure of a Generalized Bacterial Cell

Draw an annotated diagram of a generalized bacterial cell. Label all parts: cell wall, plasma membrane, cytoplasm, nucleoid (genetic material), ribosomes, plasmids, flagella, pili, and capsule. Explain the function of each part.

2. Bacterial Cell Wall – Structure and Chemical Composition

Describe in detail the structure and chemical composition of the bacterial cell wall. Explain the difference between Gram-positive and Gram-negative bacteria based on cell wall structure. Describe the role of peptidoglycan (murein) in the cell wall.

3. Endospore Formation in Bacteria

Justify the endospore formation in bacteria to withstand unfavourable conditions. Explain the process of sporulation. Describe how endospores help bacteria survive extreme temperatures, radiation, and lack of nutrients.

4. Motility in Bacteria

Explain motility in bacteria. Describe the structure of the bacterial flagellum with a diagram. Explain how flagella help bacteria move. Describe other methods of motility such as gliding and twitching.

5. Bacteria as Recyclers of Nature

Describe bacteria as recyclers of nature. Explain their role in the carbon cycle, nitrogen cycle, and decomposition. Explain how bacteria break down dead organic matter and recycle nutrients back into the ecosystem.

6. Ecological and Economic Importance of Bacteria

Outline the ecological and economic importance of bacteria. Explain their role in:

• Nitrogen fixation (Rhizobium)

• Decomposition and nutrient cycling

• Food production (yogurt, cheese, pickles)

• Industrial uses (antibiotics, enzymes, biotechnology)

• Sewage treatment

7. Use of Bacteria in Research and Technology

Explain the use of bacteria in research and technology. Describe their importance in genetic engineering, recombinant DNA technology, production of insulin, and other biotechnological applications.

8. Normal Flora and Its Benefits

Define the term normal flora. Describe the benefits of the bacterial flora of humans. Explain how normal flora:

• Help in digestion

• Produce vitamins (e.g., vitamin K, vitamin B12)

• Prevent the growth of harmful bacteria

• Stimulate the immune system

9. Structure of Model Bacteriophage

Describe the structure of a model bacteriophage (virus that infects bacteria). Draw and label its parts: head (capsid) containing genetic material, tail, tail fibers. Explain the function of each part.

10. Structure of HIV

Describe the structure of HIV (Human Immunodeficiency Virus). Draw and label its parts: outer envelope, glycoprotein spikes, capsid, reverse transcriptase, RNA genetic material. Explain the function of each part.