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Flashcards in MicroBiology- Bacteria Deck (6)
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1

BACTERIA

- Unicellular living organisms; simple internal structures and no cell organelles
- Most are smaller than any human body cells; size range of 1-5 um
- Most cases; cell is surrounded by cell wall→ major difference between human cells and bacteria

2

BACTERIA STRUCTURE

Cocci
Rods
Vibrio
Spirochaetes

3

BACTERIAL CELL WALL

- Present in most types of bacteria
- Semi-rigid outer layer→ provides mechanical support
- Differences in cell wall composition→ can mean differences in sensitivity to any particular antimicrobial

4

BACTERIAL GROWTH: GENERATION TIME

- Rapid rates of growth
- Generation time→ time taken for bacterial cell to reproduce (varies from 20mins- 20 hours)
- Even for same organisms; generation time can greatly vary depending on environmental conditions

5

DORMANCY

- Bacteria can become dormant→ cells cease metabolic activity and growth is stalled
Some cases dormant bacteria produces endospores
- This is dormant form of cell; covered by thick protective coat produced when environmental conditions= unfavourable
- Coat preserves cell inside, when conditions are favorable, the endospore germinates

6

BACTERIAL GENETICS: GENE TRANSFER

- Genes of any bacteria are present in single molecules of genes
- However; bacteria often carry additional genes (e.g. plasmids)
- Additional genes carry info to make proteins not essential for growth, but provide growth advantage
- Clinically important example→ Resistance to antibiotics
- Additional genes can be transferred between different cells (not necessarily of same species)