5 KINGDOM CLASSIFICATION SYSTEM:
Procaryotes or monera
Protista
Fungi
Plantae
Animalia
3 DOMAIN CLASSIFICATION SYSTEM
Archaea
Eubacteria
Eucaryotes
Naming and Classifying Bacteria
Genus
- a group of closely related speciesSpecies
- a population of cells with very similar characteristics. Members of a species are practically indistinguishable from each other - but there are often some minor differences.Strain
- a population of cells derived from a single cell.Sometimes bacterial names change frequently as new data comes to light. For instance in the last decade:
Pseudomonas solanacearum --> Burkholdaria solanacearum --> Ralstonia solanacearum
How do we classify bacteria into
genera and species?PRACTICAL OVERVIEW OF DIFFERENT TYPES OF ORGANISMS:
1. Prion -- infectious protein
2. Virus
- Genetic particle
- It has the information to reproduce - but only when inside cells
- No machinery of life
- One nucleic acid only - either RNA or DNA
- Protein coat - capsid, capsomeres
- May have envelope - a lipid bilayer membrane
3. Bacteria
- Procaryotic
- Single-celled organisms -- under proper conditions these cells can reproduce freely
- Has both DNA and RNA in several different organizations (chromosome, plasmid, ribosomes, etc.).
- Cytoplasm is not highly organized
- Cytoplasmic membrane
- Cell wall
- Locomotion based on flagella or axial filaments
4. Single Cell Eucaryotes
- Protozoa, Algae, Simple Fungi (Yeast)
- These are eucaryotes
- Single celled organisms - can reproduce freely under suitable conditions
- Contain both DNA and RNA - in several organizations. Much of it in the nucleus
- Cytoplasm - highly organized with many organelles and a cytoskeleton. (mitochondria, chloroplasts, various vacuoles, endoplasmic reticulum, golgi bodies, basal bodies, centrioles.)
- Locomotion based on flagella (cilia) and contraction (actin).
5. Multicellular Eucaryotes
- Higher Fungi, Plants, Animals
- Basic organization of each cell is like it is in the single-cell eucaryotes.
- Individual cells are not normally free living. They live in a "community" -- the body or soma of the organism.
- These organisms start off as a single cell.
differentiate into cells with specialized function. Differentiation is the process by which certain cells in a multicellular organism acquire a special function and organize into unique tissues. In vertebrate animals, early in the life of the organism there are many cells which can individually differentiate into a complete organism. Such cells are called stem cells.- The cell and its progeny undergo repeated rounds off division resulting in a mass of cells. At certain times different groups of cells
THE DIFFERENCE BETWEEN PROCARYOTES AND EUCARYOTES (also see chart on pg. 99 of Tortora et. al. 7th ed.)
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Procaryotes - eubacteria and archaeobacteria |
Eucaryotes - all other cells |
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Genetic info is free in cytoplasm |
Genetic info is enclosed in a membrane (nucleus). DNA is associated with proteins called histones. |
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Cell wall is usually present and it is chemically complex. In eubacteria it contains peptidoglycan (and teichoic acid in gram positive bacteria). |
Cell wall is not found in animal cells. In plants it is composed of cellulose. In fungi it is composed of chitin. These are polymers of glucose. |
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No large internal organelles. But may find smaller inclusions and bubbles. |
Many internal organelles within a highly organized cytoplasm. |
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Ribosomes are small - 70s |
Ribosomes are large - 80s; in the mitochondria and chloroplasts the mitochondria are small - 70s. |
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Locomotion with flagella made with flagellin; also axial filaments |
Locomotion with flagella and cilia composed of microtubules (tubulin and dynein); also contractile motion based on actin and myosin. |