1 (a) Which of the following best describes where 2 The list below shows three different microbes.
microorganisms live?
Tick (✓) one box.
Using this list, answer the questions below.
Underwater
(a) Which type of microbe is the smallest?
Warm, humid places
Sunny, dry areas
Nearly everywhere
(b) Which microbe is shown in the diagram below?
(b) Name two chemicals that are found in all microorganisms.
(c) Which microbes can cause disease?
3 The diagram shows fungi growing on a piece of wood.
(d) Which microbe causes influenza flu?
(e) Which microbes grow on rotting food?
(f) Which microbes are decomposers?
Fungi are decomposers.
(a) What are decomposers?
(b) Why are decomposers important?
4 Lily bought some fresh apples and lemons and placed them in a
bowl near the kitchen window. (b) The mould grew from spores on the skin of the lemons.
A few days later, Lily’s apples had turned brown and were smaller Suggest where these spores came from and how they got
and shrivelled. onto the lemon.
The lemons had green mould growing on them.
(c) The apples and lemons in Lily’s fridge still looked fresh
even though they were bought at the same time.
(a) Explain why the apples had become smaller and Suggest two reasons why.
shrivelled.
5 Organisms have important jobs in ecology. (b) Jamila investigates how temperature changes inside two
Look at the section through a composter. different composters.
Jamila:
• Uses one pile of dead plant material
• Divides the pile into two equal masses of dead
plant material
• Places one sample into composter A and the
other sample into composter B
• Measures the temperature in each composter
every 10 days.
(a) (i) What process causes the change from the
newer material to the older material inside
(i) Write down the piece of equipment Jamila
the composter?
uses to measure the temperature.
(ii) Write down the type of organism that causes
this change.
(ii) Here is Jamila’s results table. (iii) Suggest how Jamila changes the investigation
to be certain which composter has the higher
maximum temperature.
Explain why Jamila is not able to conclude
(iv) Explain why it is a good idea for Jamila to
which composter has the higher maximum
repeat her investigation.
temperature.
6 Mia investigates the rate of decomposition of slices of apple.
Mia: (c) Mia measures the mass of each slice of apple every day for
• Puts one slice of apple into each of the three dishes five days.
• Keeps the dishes at different temperatures She uses this information to calculate the rate of
• Records the mass of each slide of apple every day for five decomposition.
days. (i) Which two pieces of equipment does Mia use to
make these measurements?
(a) Write down the independent variable in this investigation.
(ii) Describe how Mia uses these measurements to
calculate the rate of decomposition.
(b) Mia wants her investigation to be a fair test.
Identify three control variables for her investigation.
