Page 218 - Big Ideas Year 10 sciPAD 2025

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218 SCIPAD - BIG IDEAS - BOOK 2
LIFE OF MICROBES
End of Chapter Review Questions
1. Name three types of microorganism: 

2. Describe why viruses are not considered living. 


3. Suggest some reasons why microbiologists study microorganisms: 




4. (a) Use the data in the table to draw a graph showing the rate of bacterial population
growth.
Time (hours) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
No. of bacteria 1 2 4 8 16 32 64 128 256
Time (hours) 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0
No. of bacteria 512 1 024 2 048 4 096 8 192 16 384 32 768 65 536
0
0
0.5 1.0
1
2
3
4
5
6
7
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0
Number of bacteria (10 000's)
Time (hours)
Bacterial Population Growth Rate
(b) Explain why the growth rate shown in your graph would not continue to increase
indefinitely. 

(c) Explain why it is best to keep food chilled. 

(d) Frozen foods can be kept for months, and even years, without spoiling. Explain this
observation. 


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