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Checkpoint Biology 0893

Grade 6 - Unit 1: Cells and organisms

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Grade 6 - Unit 4: Living organisms and classification

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Grade 6 - Unit 7: Microorganisms and food webs

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Grade 7 - Unit 1: Breathing and respiration

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Grade 7 - Unit 4: Ecosystems

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Grade 7 - Unit 7: Nutrition, health and movement

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Grade 8 - Unit 1: Cells and organisms

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Grade 8 - Unit 4: Living organisms and classification

0/12 Dr Dabour Hub Science Diagram and Course Material

Grade 8 - Unit 7: Microorganisms and food webs

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Quiz

Checkpoint Grade 6 Unit 7 – 7.3 Microorganisms And Decay

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Microorganisms And Decay Checkpoint Biology quiz: free practice for Cambridge Checkpoint Biology 0893. Work through this Microorganisms And Decay Checkpoint Biology quiz and get instant feedback on every answer. If you get stuck, review the 3.3 Microorganisms and decay lesson. More practice: Cambridge Checkpoint Biology 0893 — all units. Syllabus: Cambridge Lower Secondary programme.

  • Questions count: 50
  • Passing grade: B+
  • Time limit:
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1.
Nadia tested ways of storing strawberries from the same punnet. Which statement is best supported by her results?
Vacuum sealing works better than cooling in every case
Removing air and keeping them cold together worked best
The fridge kills the microbes on the strawberries
Removing air has no effect once the fruit is cold
2.
Before putting fallen branches on her compost heap, Mei passes them through a shredder. Why does this speed up their decay?
Shredding kills the microbes that slow down decay
The shredder adds water that the fungi need
Shredding turns the wood straight into nutrients
Small pieces have a larger surface area for microbes to work on
3.
A fallen tree trunk slowly rots on the forest floor as fungi grow through it. What happens to most of the carbon in the wood?
It is destroyed and disappears completely
It returns to the air as carbon dioxide when the fungi respire
It is turned into oxygen for the forest
It stays in the fungi for ever and never moves
4.
Kemal is planning an investigation into how temperature affects decay. Which is the best hypothesis for him to test?
Mould is disgusting and it will grow on bread
Bread will go mouldy faster at warmer temperatures because enzymes work faster
I will put bread in three places and look at it
Bread goes mouldy because of microorganisms
5.
Jamal buried 50 g of oak leaves in each type of bag in the same wood. Which is the best explanation of his results?
Dr Dabour Hub Science Diagram and Course Material
The fine mesh let in more oxygen, which slowed the microorganisms down
Earthworms are decomposers that release enzymes that digest the whole leaf
Animals such as earthworms broke the leaves into small pieces, giving microbes more surface to work on
Fewer bacteria and fungi could survive inside the coarse mesh bag
6.
Each option pairs a key term with a meaning. Which pairing is correct?
Decay – the breakdown of dead material
Compost – a microbe that feeds on dead leaves
Preservation – speeding up the rate of decay
Nutrients – enzymes released by fungi
7.
Sofia set up the four jars shown. Which two jars should she compare to find out whether water affects how fast bread decays?
Dr Dabour Hub Science Diagram and Course Material
Jars B and C
Jars A and B
Jars A and C
Jars B and D
8.
Mrs Okafor made three compost heaps of the same garden waste. Why did heap B lose much less mass than heap A?
Heap B had no water, so the microbes dried out
Without turning, little oxygen reached the decomposers in the heap
Turning heap A added extra nutrients to the waste
Heap B was too hot for the decomposers to work
9.
The graph shows how the rate of decay of grass cuttings changes with temperature. What is the best explanation for the rate at point L?
Dr Dabour Hub Science Diagram and Course Material
The microbes are working very fast, so all the grass has already gone
The microbes need more time to warm up before they start working
Hot air holds no oxygen, so the grass cannot be broken down
The high temperature has killed the microbes or damaged their enzymes
10.
Tariq wants to find out whether dung beetles speed up the breakdown of cow dung in a field. Which plan is best?
Cage equal dung pats with and without beetles in the same field, then weigh the dung left after 4 weeks
Put one dung pat in a cage with beetles and weigh it once after 4 weeks
Cage dung pats with beetles in a sunny field and without beetles in a shady wood
Count how many beetles visit dung pats in two different fields on one day
11.
Organisms that break down dead material are:
Decomposers
Producers
Herbivores
Predators
12.
Which practical work belongs to Microorganisms And Decay?
Use sterile technique and observe colonies without opening cultures
Add microorganisms to food-web models and connect decomposition with nutrient cycling
Interpret feeding relationships and check arrow direction from food to consumer
Plan an investigation into how temperature affects the rate of decay
13.
Each option pairs a place with how fast dead material decays there. Which pairing is correct?
Warm, damp heap – slow, because microbes are killed
Dry sand – fast, because air is plentiful
Fridge at 4 °C – none, because all bacteria die
Waterlogged marsh – slow, because oxygen is lacking
14.
Imagine all the bacteria and fungi in a forest disappeared. Which prediction is most likely to be correct after several years?
Plants would grow faster because nothing would rot their roots
The soil would gain more minerals because nothing uses them up
Nothing would change because animals would recycle nutrients alone
Dead leaves would pile up and new plants would grow poorly
15.
In a class investigation, each bread slice is sealed in a clear plastic bag. Why does the teacher say the bags must not be opened at the end?
Opening the bag would make the mould grow backwards
The bread would lose mass and ruin the final result
Mould releases spores that can cause allergies or illness if breathed in
Air would kill the mould before it could be counted
16.
An organism that feeds on dead material is a:
Decomposer
Parasite
Predator
Producer
17.
The diagram shows Mr Tan's garden compost bin. Which labelled feature mainly helps the decomposers to carry out aerobic respiration?
Dr Dabour Hub Science Diagram and Course Material
Q, the rows of small holes
P, the dark close-fitting lid
R, the small door at the bottom
S, the open base on the soil
18.
Chen placed a transparent grid over a bread slice to measure mould growth. Shaded squares are covered in mould. What percentage of the slice is covered?
Dr Dabour Hub Science Diagram and Course Material
10% of the slice
40% of the slice
25% of the slice
20% of the slice
19.
Frozen peas keep for months, but once defrosted and left on a warm table they spoil within two days. What does this tell you?
Freezing stopped the microbes growing but did not kill most of them
Freezing kills the microbes, so new ones must have grown from the peas
Defrosting adds extra nutrients that make decay very fast
Peas only decay once they have been frozen
20.
Lina's teacher said her plan is not a fair test. What is the best improvement?
Put all three bags in the warm cupboard at 30 °C
Add 10 cm³ of water to bag 1 and bag 2 only
Use white bread in every bag and add 5 cm³ of water to each
Use a thicker slice of bread in the fridge bag
21.
Fishermen in some coastal villages pack fish in lots of salt to preserve it. How does the salt stop decay?
It adds oxygen, which poisons the microbes
It raises the temperature above 100 °C
It draws water out of the microbes, so they cannot grow
It makes a coat that keeps the fish colder
22.
Ibrahim's class buried four items and weighed them again after 6 months. Which statement is best supported by the data?
Newspaper decayed faster than the apple core did
The cotton sock had fully decayed after 6 months
Nylon lost mass because of the water in the soil
The decomposers broke down items made from living things, but not nylon
23.
Why does soup sealed in a can stay safe to eat for years, even at room temperature?
It was heated to kill microbes, then sealed so no new ones could enter
The metal can keeps the soup cold inside
The can contains extra oxygen that stops microbes
Canned soup has had all its nutrients removed
24.
Hana left one cheese sandwich in the fridge and one in her warm school bag. Why did the sandwich in the fridge stay fresh for longer?
Cold kills all of the microbes on the sandwich
The fridge removes all the water from the bread
Microbes cannot get into a fridge because it is closed
Cold makes the microbes' enzymes work slowly, so they grow and reproduce slowly
25.
Which statement best expresses the lesson objective about Microorganisms and decay?
Explain how microorganisms cause decay
The terms decay and decomposer are always interchangeable
Evidence is unnecessary when studying Microorganisms and decay
Every model is an exact copy of reality
26.
Each option pairs a variable in a bread-mould investigation with its type. Which pairing is correct?
Area of mould – independent variable
Volume of water added – control variable
Temperature changed – dependent variable
Type of bread – dependent variable
27.
Which statement correctly describes carbon cycle?
able to be broken down by decomposers
the continuous movement of carbon between the air, living things and the ground
the use of microorganisms to break down waste in water
the continuous movement of nitrogen between the air, soil and living things
28.
Each option pairs a food preservation method with how it works. Which pairing is correct?
Canning – removes all the water from food
Drying – kills microbes using high heat
Freezing – keeps microbes too cold to grow
Salting – adds oxygen to poison microbes
29.
Aisha kept identical damp bread slices in sealed bags at three temperatures and recorded the mould cover each day. Which conclusion is best supported by her graph?
Dr Dabour Hub Science Diagram and Course Material
Mould grew faster as the temperature rose from 4 °C to 30 °C
Mould cannot grow at all when bread is kept at 4 °C
30 °C is the best temperature of all for mould to grow
Temperature made no difference until after day 4
30.
Which term is described as: a microorganism that breaks down dead material and releases nutrients?
decomposer
nitrogen cycle
carbon cycle
biodegradable
31.
Meat sealed in a vacuum pack decays slowly because most decomposers need _____ to respire.
carbon dioxide gas
bright sunlight
oxygen from the air
salt and sugar
32.
Earthworms, woodlice and millipedes are _____ that feed on dead material and break it into smaller pieces.
detritivores
producers
pathogens
predators
33.
In the diagram of how dead oak leaves are recycled, the gas labelled X is _____.
Dr Dabour Hub Science Diagram and Course Material
oxygen gas
nitrogen gas
water vapour
carbon dioxide
34.
Ama put bread slices at 5 °C, 20 °C and 35 °C. Temperature was the _____ variable because it was the one she chose to change.
dependent
independent
control variable
measured outcome
35.
In Tariq's dung beetle study, the caged dung pats with no beetles are the _____, used to compare with the pats that have beetles.
control experiment
dependent variable
prediction of results
food chain model
36.
Tube 3 shows that the carbon dioxide in tubes 1 and 2 was produced by living organisms respiring in the soil. True or false?
True – the statement is correct
False – the statement is wrong
False – heating removes the dead leaves
False – tube 3 should have changed fastest
37.
The centre of a working compost heap feels warm because the decomposers release energy as heat when they respire. True or false?
False – the statement is wrong
False – the heat comes only from sunlight
True – the statement is correct
False – decay takes in heat, so heaps are cold
38.
A compost heap should be kept dry so that the microorganisms in it do not drown. True or false?
True – the statement is correct
True, but only in summer
False – decomposers need moisture to work
True, because fungi live only in dry places
39.
Tom kept mouldy bread tests at 5 °C and 30 °C. The 30 °C slice had more mould after 5 days, so he concluded that 30 °C is the best temperature for mould. His conclusion is justified. True or false?
False – he only tested two temperatures
True – the statement is correct
True, because 30 °C was the warmer one
True, but only for white bread
40.
Decomposers release enzymes to break down material outside their cells. - True or false?
True
False
41.
Decomposers swallow large lumps of material whole. - True or false?
True
False
42.
Some microorganisms are useful to people, for example the bacteria used to make yoghurt. True or false?
True – the statement is correct
False – the statement is wrong
False – all microorganisms cause disease
False – yoghurt is made by earthworms
43.
Pickling onions in vinegar preserves them because the acidic conditions stop most microbes growing. True or false?
False – the statement is wrong
False – vinegar works by freezing the onions
True – the statement is correct
False – vinegar adds oxygen to the jar
44.
Omar wrote: "Plants get their food from the compost we add to the soil." This is scientifically correct. True or false?
True – the statement is correct
True, because compost is made of food waste
True, but only for plants without leaves
False – plants make food by photosynthesis
45.
Compost heaps are sealed airtight to speed up decay. - True or false?
True
False
46.
Viruses are the main decomposers in soil. True or false?
True – the statement is correct
True, because viruses are the smallest microbes
True, but only in wet soil
False – bacteria and fungi are the main decomposers
47.
Decay creates new nutrients that did not exist in the dead leaves before. True or false?
True – the statement is correct
True, because fungi make minerals from air
True, but only in warm weather
False – decay releases nutrients already there
48.
Pedro concluded from the table: "The more water there is in the soil, the faster the apple decays." His data support this conclusion. True or false?
False – waterlogged soil lacks oxygen, so decay was slow
True – the statement is correct
True, because the clay soil had the most water
True, but only for the sandy soil
49.
Dried apricots keep for many months because drying removes the water that microorganisms need. True or false?
False – the statement is wrong
True – the statement is correct
False – drying works by adding extra sugar
False – drying kills microbes with cold
50.
Comparing samples X and Z shows that milk does not turn sour if there are no living microorganisms in it. True or false?
False – the statement is wrong
True – the statement is correct
False – Z stayed fresh only because it was cold
False – boiling adds oxygen to the milk
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Part of Grade 6 - Unit 7: Microorganisms and food webs — see every lesson and quiz in this unit.
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