Appearance

Shapes

Division

Prokariotic

Reproduction

Asexual

Reproduce by Binary fission

May form an endospore

When conditions are suitable, endospore:

• Absorbs water
• Tough wall breaks down
• Chromosome replicates
• Cell divides as normal

Nutrition

Size

Unicellular

About 0.1 – 10 μm

Role

• Food production – lactobacillus converts milk to yoghurt and cheese
• GM bacteria – E coli make products like enzymes, insulin and drugs
• Bacteria of decay – involved in nutrient recycling

Disadvantages

• Disease – streptococci causes sore throats
• Food decay – eg lactobacilli in milk
•  

Repiration

• Aerobic – Streptococci
• Anaerobic (obligate anaerobe – requires absence of oxygen) – clostridium tetani
• Anaerobic (facultative anaerobe – respires with or without oxygen) – E-coli