Microbiology informat, Study notes of Earth science

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Introductory Microbiology

Microbial cells:

structure & function in bacteria &

archaea

Most bacterial (&

archaeal) cells

will exhibit one

of a small set of

shapes

(morphologies).

Cell arrangements often fall into common

categories.

Bauman. Microbiology with Diseases by Body System. 4th Ed. Pearson streptococci = word describing arrangement of spherical cells in chains.

Streptococcus = genus name of bacterium (that is

generally present in streptococcal arrangements!)

As cells get larger, there is a reduction in the

“surface area to volume” ratio.

Brock Biology of Microorganisms Fig. 2.

Eukaryotic cells rely upon internal membraneous networks and organelles to carry out some functions. Mitochondr ia as site of energy conservation

Osmosis is a type of passive transport, movement of water molecules across a selectively permeable membrane (e.g., the plasma membrane).

Osmosis is a type of passive transport,

movement of water molecules across a

selectively permeable membrane

Cellular organisms all have a plasma/cell membrane, cytoplasm, chromosome (DNA), ribosomes, and carry out metabolic activities.

Bacterial membranes resemble those of eukaryotes, except for …. Similar to cholesterol (animals), phytosterol (plants), ergosterol (fungi).

Brock Biology of Microorganisms Cell wall Cytoplasm Cytoplasmic membrane Cell wall Cytoplasmic membrane

The cell wall is a

protective structure

surrounding the

plasma membrane.

Staphylococcus

aureus

Some enzymes

(e.g., lysozyme)

and antibiotic

drugs (e.g., beta-

lactams) lead to

weakened bacterial

cell walls by

targeting

peptidoglycan.

Bacterial cell walls contain peptidoglycan, a strong, flexible polymer. http://www.mec.ca/product/5025-058/cactus-creek-mesh-storage-b

The backbone of peptidoglycan are the

chains (glycans) of alternating amino

sugars, NAG and NAM.

Glycosid ic (β- 1,4) bond

The 3 rd amino acid connects to an amino acid in another chain. In mature peptidoglycan, glycan chains are linked to each other by short peptides (stretches of amino acids). NAG NAG NAG NAG NAM NAM …