Author, Donkey, Bureaucrats, Administrators
53,803
edits
Changes
no edit summary
produce endospores are Bacillus and Clostridium. Endospores have a “spore coat” and are effectively in a dehydrated state with negligible metabolic activity. Due to the thermostability of endospores they can only be destroyed with certainty by moist heat at 121C for 15 mins.<br />
produce endospores are Bacillus and Clostridium. Endospores have a “spore coat” and are effectively in a dehydrated state with negligible metabolic activity. Due to the thermostability of endospores they can only be destroyed with certainty by moist heat at 121C for 15 mins.<br />
An endospore will reactivate in response to environmental factors such as exposure to heat, abrasion of the spore coat or environmental acidity. Reactivation occurs in three stages; activation, initiation and outgrowth. In the correct conditions, germination will occur in which the spore coat is degraded and water is absorbed.<br />
An endospore will reactivate in response to environmental factors such as exposure to heat, abrasion of the spore coat or environmental acidity. Reactivation occurs in three stages; activation, initiation and outgrowth. In the correct conditions, germination will occur in which the spore coat is degraded and water is absorbed.<br />
==To Incorporate==
'''Bacterial genome''':
*Contains double-stranded DNA
*Prokaryotic DNA differs to eukaryotic DNA:
**Few repeated sequences
**Most of the DNA is transcribed
**No intervening sequences within structural genes
'''Cytoplasm''':
*Does not contain mitochondria, lysosomes or Golgi bodies (found in eukaryotic cells)
*Contains mesosomes- thought to be primitive endoplasmic reticulum
'''Surface components''':[[Image:478px-Bacteria cell wall svg- franciscosp2.png|thumb|right|100px|'''Structure of cell wall''' Franciscop2 2008, WikiMedia Commons]]
*Fimbriae- also known as pili, these are hair-like structures that allow bacteria to adhere to each other
*F-type pili- also known as sex pili, these act as conjugation tubes during sexual reproduction
*Capsules/slime- serve to adhere bacteria to cells and provide protection from phagocytosis and dehydration, e.g. hyaluronic acid
*Flagella- help the bacteria move around
One way bacteria can be classified is by the structure of the cell wall:
*'''[[:Category:Gram positive bacteria|Gram-positive bacteria]]''': cell wall consists of peptidoglycan layer, with teichoic polymers attached, e.g. ''Staphylococcus''
*'''[[:Category:Gram negative bacteria|Gram-negative bacteria]]''':peptidoglycan layer is thinner, but surrounded by outer membrane of lipopolysaccharides and lipoproteins, e.g. salmonella
[[Image:427px-Arrangement of bacilli bacteria svg.png|thumb|right|100px|'''Arrangement of bacilli bacteria''' LadyofHats 2006, WikiMedia Commons]]
[[Image:497px-Arrangement of cocci bacteria svg.png|thumb|right|100px|'''Arrangement of cocci bacteria''' LadyofHats 2006, WikiMedia Commons]]
{| border="1"
|+ Components of bacterial envelope
! Component !! Gram positive !! Gram negative
|-
! Peptidoglycan
| Yes || Yes
|-
! Teichoic acid
|Yes
|No
|-
! Lipoprotein
|No
|Yes
|-
! Lipopolysaccharide
|No
|Yes
|-
! Phospholipid
|No
|Yes
|}
Another method of classification is the shape and arrangement of the bacteria themselves:
*'''[[:Category:Cocci|Cocci]]'''- round shape, e.g. Streptococci, Staphylococci, Neisseria
*'''[[:Category:Rods|Rods]]''' or '''bacilli'''- long shape, e.g. Coliforms, Bacillus, Spirochaetes
[[Category:Bacteria - Overview|A]]
[[Category:Bacteria - Overview|A]]
[[Category:To_Do_-_Bacteria]]