STUDENT ACTIVITIES
Student activity 1: Prokaryotes and eukaryotes
Use the internet and other resources to complete this table .
Feature
Prokaryotes
Eukaryotes
Examples of organisms
Number of cells
Relative size
How complex is their cell
structure?
When did they evolve?
What cell
structures/components do
they have?
 Plasma membrane
 Cytoplasm
 Ribosomes
 DNA
 RNA
 Nucleus
 Endoplasmic
reticulum
 Golgi apparatus
 Mitochondria
METABOLISM IN MICROORGANISMS (H, BIOLOGY)
© Learning and Teaching Scotland 2011
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STUDENT ACTIVITIES
 Chloroplasts
 Lysosomes
Diagram (draw or cut and
stick here or attach
separately)
Any other information
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METABOLISM IN MICROORGANISMS (H, BIOLOGY)
© Learning and Teaching Scotland 2011
STUDENT ACTIVITIES
Student activity 2: Culturing microbes
Use the internet and other resources to find out about the following topics.
These relate to the work you have just completed on how to culture microbes.
 What are spores and how do they affect the food industry?
 Describe the flash pasteurisation method of preventing contamination.
 Find diagrams and information about the filter sterilisation methods:
membrane filters and HEPA.
 How do the paper, textile and nuclear industries prevent growth of
microbes in their products?
 What do the antiseptics silver nitrate, iodine solution and hydrogen
peroxide do?
 What use do the disinfectants copper sulphate and iodine solution have?
METABOLISM IN MICROORGANISMS (H, BIOLOGY)
© Learning and Teaching Scotland 2011
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STUDENT ACTIVITIES
Student activity 3: How temperature affects the growth of microbes
Use various classroom resources to complete the following table. It relates to the three groups of microbes that thrive in different
temperature conditions.
Microbe group
Temperature
conditions and
habitats
Psychrophiles
Mesophiles
Thermophiles
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METABOLISM IN MICROORGANISMS (H, BIOLOGY)
© Learning and Teaching Scotland 2011
Examples of microbes
that live here
How they cope with
living in these
conditions, eg
adaptations they may
have
Any other information
STUDENT ACTIVITIES
Student activity 4: The effect of temperature on microbial
growth.
Equipment (this may vary depending on how you choose to set the activity
up, eg one group may do one temperature etc)
 Four agar plates Slope cultures of Bacillus subtilis and Micrococcus
Luteus, Bunsen burner and heatproof mat
 Alcohol in a beaker (to flame wire loop)
 Wire loop
 Fine marker pen for agar plates
 Sellotape
 Antibacterial wipes, gloves, goggles and other equipment required to
ensure aseptic technique
CAUTION: Do not have the beaker of alcohol near a naked flame – can
cause fire.
Method
1.
Clean the laboratory bench prior to commencing this practical to ensure
clean working conditions.
2.
Wash hands and put on gloves.
3.
Draw a dividing line on the underside of each agar plate .
4.
Label each side of the plate with a different bacteria name , eg B.
subtilis or M. luteus.
5.
Use the wire loop to inoculate one half of the plate with M. luteus. Do
this by plating a single line of the microbe over the surface of the plate
half. Take care to ensure that the agar plate is not left exposed to
airborne bacteria by keeping the lid on for as long as possible.
6.
Sterilise the wire loop by placing it in the flame, cooling it and placing
it in alcohol before re-flaming it.
7.
Repeat the inoculation with B. subtilis on the other half of the plate
once the wire loop has cooled.
8.
Tape down both sides of the plate and put your initials on it.
METABOLISM IN MICROORGANISMS (H, BIOLOGY)
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STUDENT ACTIVITIES
9.
Place the plate in the required temperature conditions: 10 , 20, 37 or
50°C.
10.
Repeat steps 5–9 if you are doing every temperature. If this is the case,
it would be easier to inoculate all four plates with one bacteria then
repeat with the other.
11.
After 24–48 hours remove the plate and look for signs of bacterial
growth. Devise a class key to determine what counts as absence , scarce,
moderate or abundant growth by observation of the plates.
For example:
absence = no bacteria growing
scarce growth = bacteria growing on 10% of the plate
moderate growth = bacteria growing on 35% of the plate
abundant growth = bacteria growing on 50% + of the plate
12.
Comment on the temperatures where the microbes grow best.
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METABOLISM IN MICROORGANISMS (H, BIOLOGY)
© Learning and Teaching Scotland 2011