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BACTERIA. Classification. Bacteria can be classified by:. Shape. Reproductive methods. Gram Staining. Types of Bacteria. Bacteria has a variety of shapes including:. Cocci. Bacilli. Sprilli. Cocci - Round. Bacilli – Rod Shaped. Spirilli – Spiral Shaped. Growth Patterns.
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Classification Bacteria can be classified by: • Shape • Reproductive methods • Gram Staining
Types of Bacteria • Bacteria has a variety of shapes including: • Cocci • Bacilli • Sprilli
Growth Patterns • Certain types of bacteria grow in characteristic patterns • Diplo: cells arranged in pairs • Strepto: cells arranged in a chain • Staphylo: cells arranged in clusters
Reproduction • Bacteria reproduce mainly by: • Asexual methods. • This happens through a type of cell division called binary fission.
Binary Fission • Bacteria don’t have nuclei so they can’t reproduce by mitosis • They copy their single chromosome which go to either end of the elongated bacterium. • A partition then builds between either end of the cell and then it divides. • Poof! An exact copy.
Conjugation • Bacteria can also exchange DNA through a process called conjugation. • A bridge between bacteria called a pilus (plural pili) allows a short, circular section of DNA called a plasmid to be exchanged between cells. • Pili allow genes to be transferred rapidly in a bacterial population.
Gram Staining • Bacteria can be divided into two groups based on the presence or absence of certain types of molecules in the cell wall.
Gram Positive • Have a thick carbohydrate cell wall and stains purple Good Ones: Yogurt-making bacteria, antibiotic production, pickling bacteria, digestive bacteria Bad ones: Some forms of tetanus, pneumonia and botulism.
Gram Negative • Have an extra layer of lipid on the cell wall that stains pink. • Antibiotics aren’t very effective for this bacteria. (ask if you’re interested why) Many nitrogen-cycle bacteria are gram negative as well as cyanobacteria.
Archaebacteria • Find the textbook section on Archaebacteria • Describe characteristics of this Kingdom • Identify some representative Archaebacteria • Explain why you think studying Archaebacteria may be relevant today. Essentially…. Why bother??
Archaea • Live in very difficult environments. Often classified by the environment they live in. • Halophiles: live in high-salt environments • Thermophiles: Live in high-temperature environments • Acidophiles: live in acidic environments • Also classified by what they use for food • Methanogenicarchaea make methane as a part of their metabolism. • Chemosynthetic bacteria use other chemicals than oxygen to help them produce energy.