Bacteria are unicellular prokaryotes that can be heterotrophs or autotrophs. They have a cell membrane, cell wall, cytoplasm, and genetic material but lack organelles. Bacteria can be classified based on their shape as cocci, bacilli, vibrios, or spirilla. They reproduce through binary fission and can form spores during sporulation. Environmental conditions influence their growth and reproduction rates.

1. What are bacteria like?
flagellum
genetic
material
capsule
cell wall
• Unicellular
• Prokaryote cytoplasm cell
• Most are heterotrophs. membrane
• Some form colonies.
• Habitat: all types

2. Bacteria nutrition
Heterotrophs Autotrophs
Parasites
Saprophytes
Symbionts Photosynthesis

3. Bacteria nutrition
• feed off living things Parasites
Heterotrophs • cause illnesses
(tuberculosis, cholera)
• live on dead or
decomposing matter
• are used to make food
Saprophytes
milk
• live in the bodies
cheese
of other living
things yoghurt
Symbionts
intestinal bacteria

4. Bacteria nutrition
Autotrophs cyanobacteria
carbon dioxide
P
H
O
T
O
S
Y
N
T
H
E
S
I
S
oxygen
+
organic substances

5. How are bacteria classified?
Coccus Vibrio
curved -
spherical rod shaped
Bacillus Spirillum
rod-shaped helical

6. How do bacteria reproduce and interact?
Binary fission Sporulation Environmental
minutes conditions
0
unfavourable
30
resistant
spores
60
favourable
90
growth of bacteria
1.500
1.000
amount 50
of bacteria
(in millions) 5 15 20 Time (in hours)