1 Bacteria Archaebacteria and Eubacteria 2 2 Kingdoms

1 Bacteria Archaebacteria and Eubacteria

2 2 Kingdoms of Bacteria • Eubacteria • Archaebacteria

3 5 Characteristics of ALL Bacteria • All are unicellular; some stick together in colonies • Cells are prokaryotic. Bacteria usually lack membrane-bound organelles such as nucleus, vacuoles, mitochondria or chloroplasts • Cells usually have a single chromosome in the form of a DNA loop • Cells reproduce asexually by binary fission • Cells thrive in most environments and become inactive if the environment dries up.

4 2 Categories of Cells (based on their complexity) • Eukaryotic ▫ “true nucleus” ▫ has nucleus + other membrane-bound organelles ▫ ex. Plant and Animal cells

5 2 Categories of Cells – con’t • Prokaryotic ▫ “before nucleus” ▫ No nucleus, so DNA floats freely in the cell ▫ 2 types of genetic material a) A DNA loop (circular chromosome) b) A small piece of floating DNA (also circular) called a PLASMID

6 Archaebacteria • Archae = early or primitive • May be the first organisms on Earth (ie. Evolved that early) • Live in extreme conditions (where nothing else can live); many wihtout oxygen • 3 groups of Archaebacteria 1. Thermophiles 2. Methanogens 3. Halophiles * Are very useful to humans

7 Thermophiles • Live in extremely hot environments (over 45 C) • Get energy from respiration using sulfur • Live in hot sulfur springs

8 Methanogens • Live on carbon dioxide and hydrogen and make methane • Live in deep-sea vents, swamps and mammalian intestines (even humans)

9 Halophiles • Live in extremely salty places like salt flats (makes the ground purplish-red due to their pigments) • Capable of using sunlight to make energy

10 Eubacteria • Cell walls contain peptidoglycan (no cellulose) • Can be both helpful and harmful to humans (ie. can cause disease)

11 Eubacteria – con’t • Ex. Escherichia coli (E. coli) • Helpful: ▫ lives in human intestines ▫ Help digest food ▫ Help make vitamins K and B • Harmful: ▫ Can cause disease if it contaminates water supplies (ie. from feces)

12 E. Coli – A Rod-Like Bacterium D - Pili (sing. Pilus) – for attaching to other bacteria and movement E - Genetic material – circular DNA chromosome “floats” in the cytoplasm and plasmids I - Cytoplasm – not divided in compartments H - Cell membrane – regulates movement in and out A - Flagellum – movement, rotates like a propeller G - Cell wall – made of peptidoglycan F - Capsule – sticky protective covering

13 Eubacteria – con’t • 4 ways to classify Eubacteria 1. 2. 3. 4. Shape Configuration Respiration Type of Nutrition

14 1. Shape • 3 basic shapes: a) Spherical b) Rod-like c) spiral

15 2. Configuration • Many bacteria stay together in groups • Can be single, pairs, chains (filaments) or cluster colonies • Cocci ▫ ▫ monococcus (1) Diplococcus (2) Streptococcus (chain) Staphylococcus (clump)

16 3. Respiration • Some bacteria are aerobic (need oxygen to survive) ▫ Ex. Tuberculosis bacteria • Some bacteria are anaerobic (can only grow if there is no oxygen) ▫ Ex. Tetanus, botulism

17 4. Type of Nutrition • Some are autotrophs (make their own food) ▫ Ex. Photosynthesis bacteria use sunlight to make food photosynthesis ▫ Chemosynthetic bacteria use chemical reactions to make food chemosynthesis • Some are heterotrophs (obtain nutrients from the organisms) ▫ Parasites (causing disease feeding on living tissue) ▫ Decomposers (feeding on dead matter)

18 Reproduction and Growth of Eubacteria and Archaebacteria • Two methods of reproduction: 1. Sexual 2. Asexual 1. Sexual reproduction ▫ Sexual reproduction is not common in bacteria, but it does happen. It is called conjugation. In conjugation the bacteria form a bridge called a sex pilus, and the bacteria exchange plasmids.

19 Reproduction and Growth of Eubacteria and Archaebacteria – con’t 2. Asexual Reproduction ▫ bacteria reproduce asexually by binary fission. Binary fission is like mitosis: one cell duplicates its genetic material, then the cell pinches in two, giving 2 complete new daughter cells. The daughter cells may separate, or stay attached, forming a chain or colony.

20 Dormancy • If conditions are not favorable for a bacterium to grow, bacteria can form a special type of cell called an endospore. An endospore is a small cell with a thickened cell wall that protects it, so it can survive extreme heat, dryness, etc. When conditions improve, the bacterium goes back to normal.