MicroBiology- Bacteria

Question 1

BACTERIA

Answer 1

• 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

Question 2

BACTERIA STRUCTURE

Answer 2

Cocci
Rods
Vibrio
Spirochaetes

Question 3

BACTERIAL CELL WALL

Answer 3

• 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

Question 4

BACTERIAL GROWTH: GENERATION TIME

Answer 4

• 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

Question 5

DORMANCY

Answer 5

• 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

Question 6

BACTERIAL GENETICS: GENE TRANSFER

Answer 6

• 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)