Science 8
Unit 3 - Reproduction – Asexual Reproduction Activity
Population Growth by Binary Fission
Suppose you get on a bus to go to school. At 8:20 am, you yawn, and a
single Streptococcus bacterium floats into your open mouth and settles in
your throat. Under ideal conditions, that bacterium can reproduce in 20
minutes. Therefore, by the time the bus drops you off at school at 8:40 am
there are two bacteria in your throat. When your class starts at 9:00 am,
there are four.
1.
Assuming that bacteria reproduce asexually by binary fission every 20 minutes.
complete the following table:
DataTable 1 - Bacterial Growth
Time
8:20
Number
of
bacteria
in throat
1
Time
8:40
12:20 12:40
9:00
1:00
9:20
1:20
9:40 10:00 10:20 10:40 11:00 11:20 11:40 12:00
1:40
2:00
2:20
2:40
3:00
3:20
3:40
4:00
Number
of
bacteria
in throat
2.
Data: On the graph paper provided, create a graph showing the population growth of the
bacteria from 8:00 am to 10:40 am.


Put time (minutes) along the horizontal (left/right) axis
Put bacterial growth (number of bacteria) along the vertical (up/down) axis.
3.
What time do you think your throat will start to feel sore? Why?
4.
Streptococcus bacteria is a living organism and as such it needs the proper conditions for
survival. Do you think this bacterium can keep growing like this forever? Explain your
answer.
5.
The bacteria that causes you to have “strep throat” is a prokaryote which reproduces
asexually. What type of asexual reproduction does it perform?
6.
We know that bacteria reproduce asexually. So, if you are prescribed antibiotics (such as
Amoxicillin) that inhibit the normal function of Streptococcus bacteria, what will happen?
7.
If a mutation occurs, and a bacterium develops a mutation that makes it antibioticresistant to Amoxicillin, what could happen?
Graph 1 – A Graph of Bacterial Growth vs. Time