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Honors Biology

Explore the fascinating world of genetic exchange in bacteria through conjugation, transformation, and transduction. Learn about bacterial colonies, shapes, and classification in Kingdom Monera.

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Honors Biology

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  1. Honors Biology Module 2 Kingdom Monera Part 2 September 12, 2013

  2. Class Challenge Your favorite Sports team: Super Fan

  3. Questions from Homework?

  4. Quiz: ID the 3 Basic Shapes of Bacteria

  5. Quiz Identify as Asexual Reproductionor Sexual Reproduction 4. The offspring is a genetic copy of the parent. ___________ 5. Each parent contributes to the DNA, and the offspring’s DNA is a blend of parents’ DNA. ____________

  6. 6. Once the cell wall and plasma membrane elongate, and separate the copy cell (daughter cell) from the original, two cells are now created. What is this an example of ? == == ==

  7. Asexual • Sexual • Asexual Reproduction

  8. Genetic Recombination in Bacteria When bacteria reproduce asexually, the offspring is a genetic copy of the parent. However, when bacteria exchange genetic information in order to increase the genetic diversity of the population in one of three ways:

  9. Conjugation • Transformation • Transduction

  10. ConjugationFigure 2.6 Is a temporary union of two organisms for the purpose of DNA transfer. Plasmid- 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.

  11. The first step in conjugation among bacteria involves the donor grasping the recipient with its sex pili. Sex pili are also fimbriae that re used in reproduction. The donor bacterium is the one that initiates conjugation. Once the donor grasps the recipient, a conjugation tube is formed between the bacteria. Then the donor bacterium transfers one of the plasmid’s strands to the recipient.

  12. Bacteria Conjunction • https://youtu.be/EtxkcSGU698

  13. Transformation Is the transfer of a DNA segment from a nonfunctional donor cell to that of a function recipient cell. If a bacterium dies, its cell wall falls apart and the components of the cell (including the DNA) flow into the surroundings. The dead bacterium’s DNA seems to break into small; pieces and the living bacterium might “sense” that on or more of those pieces contains a trait or traits it could use. So the living bacterium then absorbs what it needs, incorporating the new genetic information as a plasmid.

  14. Transformation in Bacteria https://youtu.be/MRBdbKFisgI

  15. Once a bacterium has such a plasmid, it might then engage in conjugation to pass the plasmid on to other bacteria.

  16. Transduction Is the process in which infection by a virus results in DNA being transferred from one bacterium to another. So a virus can pick up DNA from a bacterium during infection and that DNA can be inserted into another bacterium in a subsequent infection.

  17. Genetic Transfer - part 1 (4:52) http://youtu.be/t4i0Q_irM8o Genetic Transfer - part 2 http://youtu.be/XPvuc9j1t-k

  18. Transduction • https://youtu.be/An9oItt7U9I

  19. Bacterial ColoniesFigure 2.7 The bacteria’s ability to survive is usually enhanced when they form a colony. There are 3 basic shapes of bacteria • Coccus (spherical) • Bacillus (rod-shapped) • Spirillum (helical)

  20. Bacterial Colonies A bacterial colony is just a simple association of individual bacteria. Each bacteria could survive on its own if separated. Some colonies will secrete a capsule-like substance that surrounds and protects the entire colony. It is slimy and holds the colony together. (Stagnant ponds often have the look of floating mats on top of the water.)

  21. Bacterial Colonies Some colonies work together to capture and eat prey. When they find it, they engulf it and as a group secrete a substance that digests it. The entire colony then feeds on the nutrients. They can be found in soil, are thin rod shaped, gram-negative cells that exhibit self-organizing behavior as a response to environmental cues. The swarm, which has been compared to a "wolf-pack," modifies its environment through stigmergy. This behavior facilitates predatory feeding, as the concentration of extracellular digestive enzymes secreted by the bacteria increases.

  22. Myxococcus Xanthus Colony

  23. Classifying Kingdom Monera Bacteria is so diverse, we will only be dividing it into two different phyla’s : Using the Gram Stain, certain bacteria look blue under the microscope, while others looked red. (see figure 2.8) Now this is used to classify bacteria.

  24. See Table 2.1 on page 55. Partial Classification of Kingdom Monera

  25. Classifying Bacteria If the bacteria has a cell wall that doesn’t retain the Gram stain (making it Gram Negative – Red stain), it belongs to phylum Gracilicutes. Three Classes: • Scotobacteria: non-photosynthetic (Lyme and many other pathogenic bacteria) • Anoxyphotobacteria: photosynthetic that do not produce oxygen. (live in sediments of lakes or rivers.) • Oxyphotobacteria: photosynthetic bacteria that produce bacteria. (blue-green algae)

  26. Bacteria that have a cell wall that retains the Gram stain (making them Gram-positive – Blue stain) belong to phylum Firmicutes. Two Classes separated by their shapes: • Firmibacteria: containes cocci and bacilli • Thallobacteria: spirillum (helical) shaped

  27. Bacteria that has no cell wall are in phylum Tenericutes. One class: • Mollicutes: contains pneumonia-causing bacteria. .

  28. Lastly, bacteria possess cell walls, but the compounds which form these walls are rather different from the compounds that form the cell walls of Gram-positive and Gram-negative bacteria. They are in a separate phylum Mendosicutes One Class: Archaebacteria: has all the bacteria with exotic cell walls (live in deep ocean vents, brackish seas like the Great Salt lake) Many places that are uninhabitable to other organisms are populated with members of this class.

  29. Conditions for Bacterial Growth • Moisture • Moderate temperature • Nutrition • Darkness • The proper amount of oxygen

  30. Remember there is a great diversity among bacteria and these conditions are only the most important conditions for bacterial growth. Bacteria is generally very specialized in terms of their habitat.

  31. Preventing Bacterial Infections • Food becomes infected as it is exposed to the air. What is in the air? • What can you do to prevent bacterial growth on food?

  32. Think about the conditions that promotes bacteria’s growth… • Moisture • Moderate temperature • Nutrition • Darkness • The proper amount of oxygen

  33. Cover the food and seal it. • Heat or cook the food • Refrigerate it • Dehydrate • Freeze • Pasteurization (milk)

  34. How about if you cut yourself? What should you do to help fight infection (bacterial growth)?

  35. Experiment 2.2Pond Life, Part B

  36. Homework • Complete On Your Own Questions • Complete Study Guide Questions • Complete Experiment 2.2 in Lab book • Take Module 2 Test • Read Module 3 p.67-79 • Class challenge: Guy Harvey Day • Quiz: ID: Conjugation, Transformation, and Transduction; The 5 conditions that promote bacterial growth; Name and Draw the 3 shapes of bacteria.

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