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EIN-O’s INTRO Almost all living things are composed of one or many more cells. Scientists group cells into two types: eukaryote and prokaryote cells. •Animals and plants are made of eukaryote cells. •Bacteria are prokaryote cells. Eukaryote cells have internal compartments and are more complex than prokaryote cells. Prokaryote cells are usually much smaller than eukaryote cells and their internal components are not so well organized. However, no matter which type of cell we look at, cells have certain features in common: They have an outer layer (called a cell membrane),


they contain a fluid material (called cytoplasm), and they possess genetic material. Eukaryote cells have internal compartments and are more complex than prokaryote cells. Prokaryote cells are usually much smaller than eukaryote cells and their internal components are not so well organized. However, no matter which type of cell we look at, cells have certain features in common: They have an outer layer (called a cell membrane), they contain a fluid material (called cytoplasm), and they possess genetic material.


Getting things in to scale Animal and plant cells are about ten to a hundred times smaller than a millimeter or 100 - 10 um (scientists call this 100 or 10 microns). This is 0.1 – 0.01 mm. 100um

10um

1um

100 nm

10 nm

BACTERIA CELLS ANIMAL & PLANT CELLS

VIRUSES

0.1mm

0.01mm

0.001mm

0.0001mm

0.00001mm


Bacteria cells are about a hundred to a thousand times smaller than a millimeter of 10 – 1 um (10 or 1 micron). This is 0.01 – 0.001 mm. Viruses are about ten thousand to a hundred thousand times smaller than a millimeter (scientists call this 100 – 10 nanometers). This is 0.0001 – 0.00001 mm. The Bio Signs Cell and Microbiology series is an assortment of 6 cell and microbiology models. The detailed models are the: Animal Cell, Plant Cell, White Blood Cell, Red Blood Cell, Bacteria, and Virus. This I Know Guide provides an introduction to: a Bacteria Cell


BACTERIA CELL Bacteria cells are prokaryote cells. Compared with eukaryote cells, prokaryote cells are less organised. Prokaryote cells are simpler than the complex eukaryote cells. Bacteria cells are single-celled microorganisms that can survive by themselves. They can repair themselves and make new materials. The majority of bacteria are harmless to humans, but there are some that cause


damage and disease to humans or other living organisms. Some common features found in a bacteria cell are: Cell Membrane and Cell Wall, Genetic Material, Protoplasm, Ribosomes, Flagellum.

Ein-O Facts •Bacteria are the most common microorganisims in the world.


Cell Membrane & Cell Wall All bacteria cells have a cell membrane that is like a barrier, rather like skin. It allows a few molecules to pass through it but mainly serves to keep the cell contents in the cytoplasm. In addition to the cell membrane, some bacteria cells have sturdy cell walls that are located outside the cell membrane. Bacteria have a sugar-protein chemical called peptidoglycan (peptee-dough-gli-can) in their cell walls.


Genetic Material Bacteria cells have DNA that is formed in a bundle shape. This bundle of genetic material has no nuclear envelope to surround it so it just floats around in the protoplasm.

Protoplasm The protoplasm is the fluid-like material inside the bacteria cell. It helps to maintain the shape of the cell as well as allowing molecules and genetic material to move around.


Ribosomes Ribosomes are small structures that help make proteins from amino acids. In bacteria cells, they float around in the protoplasm.


Flagellum This tail-like structure helps the bacteria move or “swim�. Not all bacteria have flagella, but many do.


Copyright Š COG 2005 All rights reserved. No part of this book may be reproduced or copied in any form without written permission from the publisher.

609028_bacteria  

Bacteria user reference manual

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