General characteristics of Bacteria
Bacteria single cell organism.
Lack organelles such as chloroplasts and mitochondria.
They donot have true nucleus.
Lack of membrane bound organelles.
Bacteria are classified as prokaryotes, which are single cell organism.
Genetic information is in circular loop called plasmid (instead of having chromosomal DNA).
Strong cell wall; resistant to environmental changes.
Bacteria will produce rapidly by binary fission, asexual process, one bacteria can split into two every 10-15minutes.
An unfavorable condition, bacteria survive by becoming dormant form spore, thick protective coat around them.
Bacteria also have cell membrane and cell wall called cell envelope, made up of peptidoglycan.
Three main shapes of bacteria;
Coccus; spherical or oval shape
For example; streptococcus group (strep throat)
Spiral; spiral shape
For example; Spirochaetes
Bacillus; rod shaped bacteria
For example; Bacillus Anthrax
Gram staining is method of staining bacteria, uses for general identification of bacteria.
1. Gram +ve bacteria
Appear violet, because have thick cell walls that trap crystal violet-iodine complex
2. Gram -ve bacteria
Appear red/pink, because thin cell wall of gram -ve bacteria can't hold violet-iodine complex but they hold safaranin.
Found capsule; outside of cell wall of some bacteia.
Flagellum; Used for movement
Pilli; Hair-like structure on outside cell allow it to stick to surface and transfer genetic material to other cells; contribute spread of illnes in human.
Areobes or aerobic bacteria; Can grow in oxygen
Anaerobes or anaerobic bacteria; grow where no oxygen (in human G.I track)
Facultative anaerobes; live either with or without oxygen.
Bacteria take in nitrogen and release it for plant use when they die.
Some bacteria are antimicrobial resistance.
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