BLG 143 Study Guide - Final Guide: Nucleoid, Dna Supercoil, Cell Membrane
27 Apr 2018
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Chapter 7 – Inside the Cell
7.1 Bacterial and Archaeal Cell Structures and Their Functions
According to morphology (form science), there are 2 broad groupings of life:
1. Prokaryotes lack membrane-bound nucleus
2. Eukaryotes have membrane-bound nucleus
According to phylogeny/evolutionary history, there are 3 domains:
1. Bacteria (prokaryotic)
2. Archaea (prokaryotic)
3. Eukarya (eukaryotic)
Prokaryotic Cell Structure
Chromosome
• Most prominent structure inside a bacterial cell
• Single, circular chromosome that consists of a large DNA molecule associated with a
small number of proteins
• DNA molecule contains information
• Proteins provide structural support for the DNA
• Contain DNA which contains genes segment of DNA that contains information for
building an RNA molecule or a polypeptide
• Supercoiled to fit into the cell, the DNA double helix coils on itself with the aid of
enzymes to be highly compact
• Found in localized area nucleoid
Nucleoid is found in the centre of the cell and typically represents about 20% of the cell’s
total volume. Genetic material in the nucleoid is not separated from the rest of the cell
interior by a membrane.
Plasmids
• Small, supercoiled, circular DNA molecules
• Contain genes that help the cell adapt to unusual environmental conditions
• Physically independent of the main cellular chromosome
Ribosomes observed in all prokaryotic cells and are found through the cell interior;
consist of RNA molecules and proteins for protein synthesis
Organelles
• Internal compartments
• Membrane bound
• Contains enzymes/structures specialized for a particular function
• Each type of bacterial organelle is found in certain species
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Document Summary
7. 1 bacterial and archaeal cell structures and their functions. According to morphology (form science), there are 2 broad groupings of life: prokaryotes lack membrane-bound nucleus, eukaryotes have membrane-bound nucleus. According to phylogeny/evolutionary history, there are 3 domains: bacteria (prokaryotic, archaea (prokaryotic, eukarya (eukaryotic) Nucleoid is found in the centre of the cell and typically represents about 20% of the cell"s total volume. Genetic material in the nucleoid is not separated from the rest of the cell interior by a membrane. Plasmids: small, supercoiled, circular dna molecules, contain genes that help the cell adapt to unusual environmental conditions, physically independent of the main cellular chromosome. Ribosomes observed in all prokaryotic cells and are found through the cell interior; consist of rna molecules and proteins for protein synthesis. Internal compartments: membrane bound, contains enzymes/structures specialized for a particular function, each type of bacterial organelle is found in certain species. Cytoplasm (cell formed) bilayer or attach to one side.
