Bacteria: Properties


source: http://www.youtube.com/watch?v=TDoGrbpJJ14&feature=BFa&list=WL640C1A6AB0331DB2&index=1

What is Bacteria? CLICK LINK BELOW FOR GREAT NOTES

Kimball's Biology Pages: Bacteria

KEYTERMS:

WHAT IS THE CELL WALL COMPOSED OF?
Peptidoglycan, also known as murein, is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of bacteria (but not Archaea), forming the cell wall. The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine and N-acetylmuramic acid. Attached to the N-acetylmuramic acid is a peptide chain of three to five amino acids. The peptide chain can be cross-linked to the peptide chain of another strand forming the 3D mesh-like layer.[1] Some Archaea have a similar layer of pseudopeptidoglycan or pseudomurein, where the sugar residues are β-(1,3) linked N-acetylglucosamine and N-acetyltalosaminuronic acid. That is why the cell wall of Archaea is insensitive to lysozyme.[2] Peptidoglycan serves a structural role in the bacterial cell wall, giving structural strength, as well as counteracting the osmotic pressure of the cytoplasm. A common misconception is that peptidoglycan gives the cell its shape; however, whereas peptidoglycan helps maintain the structure of the cell, it is actually the MreB protein that facilitates cell shape[citation needed]. Peptidoglycan is also involved in binary fission during bacterial cell reproduction.
The peptidoglycan layer is substantially thicker in Gram-positive bacteria (20 to 80 nanometers) than in Gram-negative bacteria (7 to 8 nanometers), with the attachment of the S-layer. Peptidoglycan forms around 90% of the dry weight of Gram-positive bacteria but only 10% of Gram-negative strains. Thus, presence of high levels of peptidoglycan is the primary determinant of the characterisation of bacteria as gram-positive.[3] In Gram-positive strains, it is important in attachment roles and stereotyping purposes.[4] For both Gram-positive and Gram-negative bacteria, particles of approximately 2 nm can pass through the peptidoglycan.[5]
source: http://en.wikipedia.org/wiki/Peptidoglycan
source: http://www.micro.siu.edu/micr425/425Notes/01-Introduction.html

HOW DO THEY MOVE?



A flagellum (play /fləˈɛləm/; plural: flagella) is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and functions in locomotion.[1][2][3] There are some notable differences between prokaryotic and eukaryotic flagella, such as protein composition, structure, and mechanism of propulsion. An example of a flagellated bacterium is the ulcer-causing Helicobacter pylori, which uses multiple flagella to propel itself through the mucus lining to reach the stomach epithelium.[4] An example of a eukaryotic flagellated cell is the sperm cell, which uses its flagellum to propel itself through the female reproductive tract.[5] Eukaryotic flagella are structurally identical to eukaryotic cilia, although distinctions are sometimes made according to function and/or length.[6]
The word flagellum is the Latin word for whip.
source: http://en.wikipedia.org/wiki/Flagellum


source: http://www.cartage.org.lb/en/themes/sciences/zoology/animalphysiology/anatomy/animalcellstructure/CiliaFlagella/CiliaFlagella.htm

source: http://www.phy.duke.edu/undergraduate/biophysics/
source; http://www.newworldencyclopedia.org/entry/Flagellum
source: http://www.ruf.rice.edu/~rau/phys600/whitesides.htm

HOW DO THEY REPRODUCE?

binary fission
[bī′nərē]
Etymology: L, bini, twofold, fissionis, splitting
the division of a cell or nucleus into two equal parts. It is the common form of asexual reproduction among bacteria, protozoa, and other unicellular organisms. Also called simple fission. Compare multiple fission.
Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.
source: http://medical-dictionary.thefreedictionary.com/binary+fission

source: http://faculty.fmcc.suny.edu/mcdarby/majors101book/Chapter_04-Cell_Structure&Function/03-cell_functions.htm
source: http://www2.estrellamountain.edu/faculty/farabee/biobk/biobookmito.html
HOW DO THEY GET THEIR NUTRITION?
TWO WAYS: AUTOTROPIC AND CHEMOTROPIC

Autotrophic

Definition
adjective
1. Of or relating to an autotroph, an organism capable of making nutritive organic molecules from inorganic sources via photosynthesis (involving light energy) or chemosynthesis (involving chemical energy).
2. Self-sustaining or self-nourishing organisms (e.g. green plants, algae, and certain bacteria) that have the ability to synthesize their own food from inorganic materials, e.g. carbon dioxide and nitrogen.

Supplement

Related forms: autotroph (noun), autotrophy (noun).
Compare: heterotrophic.
See also: photosynthetic, chemosynthetic.
source: http://www.biology-online.org/dictionary/Autotrophic
Chemotropic (adj)
che·mot·ro·pism (k-mtr-pzm)
n.
Movement or growth of an organism or part of an organism in response to a chemical stimulus.

chemo·tropic (km-trpk, km-) adj.
source; http://www.thefreedictionary.com/chemotropic

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