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REPRODUCTION IN BACTERIA- AN INTRODUCTION
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- 2. 2 REPRODUCTION • There aretwo types of reproductions in bacteria that are • Asexual reproduction • Sexual reproduction
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- 4. Asexual Reproduction Asexual reproductionin bacteria includes several methods. Here are details on those "other methods" summarized earlier: 1) Budding: • In this method, a small protuberance or bud forms on one side of the parent bacterial cell. • The cell’s DNA replicates, and one copy moves into the bud along with some cytoplasm. As the bud grows, it eventually separates from the parent cell as an independent daughter cell. Examples: • It include bacteria like: i. Hyphomicrobium vulgare ii. Rhodomicrobium vannielia. • Budding differs from binary fission in that the daughter cell may be smaller initially and the mother cell remains mostly unchanged in size during the process. 4
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- 6. 6 Continue…. 2) Fragmentation: Some filamentousbacteria reproduce by breaking into several fragments. Each fragment can grow into a new individual bacterium identical to the parent. 3) Spore Formation: a. Endospores: • Formed under harsh conditions. • Endospores are tough, dormant structures that can survive extreme environmental stress. • When conditions improve, they germinate to form active bacterial cells. b. Conidia: • These are asexual spores formed by some bacteria • These bacteria can disperse and grow into new individuals.
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- 9. 9 Continue…… 4) Cyst Formation: •Some bacteria form cysts that are dormant, thick-walled resting cells to survive unfavorable environmental conditions. • When favorable conditions return, cysts can reactivate and resume growth.
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- 11. 11 Continue….. 5) Binary Fission •Binary fission is the primary method of asexual reproduction in bacteria. It's a simple, efficient process that allows bacteria to rapidly multiply and adapt to their environment. • The bacterial DNA replicates, resulting in two identical copies • The bacterial cell grows and elongates. • A septum (cross-wall) forms in the center of the cell. • The septum divides the cell into two daughter cells • The daughter cells separate, each with a complete set of genetic material
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- 13. SEXUAL REPRODUCTION • Sexualreproduction in bacteria, known as genetic recombination. • It involves the exchange of genetic material between bacterial cells, enhancing genetic diversity. • The main methods are: i. Conjugation ii. Transformation iii. Transduction • Each with distinct processes
- 14. CONTINUE…… 1. Conjugation: • Thisis a direct cell-to-cell transfer of DNA, usually plasmids, from a donor (F+ cell) to a recipient (F- cell). • The donor produces a sex pilus that attaches to the recipient and draws the cells together. • A relaxase enzyme then nicks the plasmid DNA at a specific site (oriT), unwinding one strand, which is transferred through the pilus into the recipient. • Both cells then synthesize complementary DNA strands, resulting in both being capable donors. • This method is significant for spreading traits like antibiotic resistance. Click icon to add picture
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- 16. 16 CONTINUE…… 2. Transformation: • Bacteriatake up free DNA fragments released from dead bacteria in their environment. • This foreign DNA integrates into the recipient's genome, allowing the acquisition of new genetic traits.
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- 18. 18 CONTINUE….. 3. Transduction: • Geneticmaterial is transferred from one bacterium to another via bacteriophages (viruses that infect bacteria). • During infection, phages accidentally incorporate bacterial DNA and transfer it to a new host upon subsequent infection, facilitating genetic exchange.
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- 21. 21 CONTINUE…… • These sexualmechanisms do not produce offspring like conventional sexual reproduction but serve to mix genetic material, contributing to bacterial adaptability and evolution.
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