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Checkpoint Biology 0893

Grade 6 - Unit 1: Cells and organisms

0/11 Dr Dabour Hub Science Diagram and Course Material

Grade 6 - Unit 4: Living organisms and classification

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Grade 6 - Unit 7: Microorganisms and food webs

0/11 Dr Dabour Hub Science Diagram and Course Material

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

0/10 Dr Dabour Hub Science Diagram and Course Material
Quiz

Checkpoint Grade 8 Unit 7 – 7.3 Microorganisms And Decay

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Microorganisms And Decay Checkpoint Biology quiz set 2: free practice for Cambridge Checkpoint Biology 0893. Work through this Microorganisms And Decay Checkpoint Biology quiz set 2 and get instant feedback on every answer. If you get stuck, review the 9.3 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:
Start Quiz
1.
Which statement correctly describes variable?
breakdown of organic matter
an organism that breaks down dead material
a type of fungus
a factor that can change
2.
Which of these is the FIRST step in the correct order?
change one variable
measure decay
use results to form a conclusion
state a hypothesis
3.
A shop worker notices a can of beans with bulging ends. What is the most likely cause?
Beans grow larger when canned food is stored
Heat in the shop made the metal of the can grow
The beans photosynthesised and made oxygen
Microbes got in and their respiration made gas
4.
Sipho kept cucumber slices in liquids with different amounts of vinegar for 5 days at 20 °C. Which conclusion is best supported?
Dr Dabour Hub Science Diagram and Course Material
Vinegar has no effect until it reaches 20%
5% vinegar stops all bacteria from growing
Bacteria grow best in acidic conditions
The more vinegar, the fewer bacteria grew
5.
Use the table. What is the best explanation for the pattern?
Drying made the apricots warmer, which slowed mould
Less water in the fruit slowed microbial growth
Drying added sugar, which the mould could not use
Wetter apricots had fewer microbes on them
6.
Which statement correctly describes decomposer?
breakdown of organic matter
a type of fungus
a factor that can change
an organism that breaks down dead material
7.
Archaeologists digging in an old landfill site found a newspaper from 1985 that could still be read. What is the best explanation?
Dr Dabour Hub Science Diagram and Course Material
Newspaper is not made from living material, so it cannot decay
The heat inside the landfill had killed all the fungi
Pressed layers and a cap left little oxygen for decomposers
Light shining into the landfill stopped decay
8.
Tomas wants to find out whether earthworms speed up the decay of leaves. Which plan is best?
Two identical soil tanks with equal leaf mass; worms in one; compare dry mass later
One tank with worms and leaves; check whether any leaves are left after a week
Two tanks, one warm and one cold, both with worms and a handful of leaves
Two tanks with worms, one with oak and one with grass; compare the colour
9.
Ana measured the decay of leaves by weighing them. Why is it better to dry the leaves in an oven before weighing them at the start and the end?
Drying kills the decomposers so decay goes faster
Wet leaves are too heavy for the balance to weigh
Water content varies, so only dry mass shows decay
Oven drying adds nutrients to the leaves
10.
Use the table. Why did the wetter bales become much hotter than the barn air?
More microbes grew and respired, releasing heat
Water in the bales absorbed heat from the Sun
The mould made the hay photosynthesise faster
Wet hay has a higher boiling point than dry hay
11.
Earthworms and fungi both help dead leaves decay. How are their roles different?
Worms make leaves by photosynthesis; fungi eat them
Worms break leaves into pieces; fungi digest them with enzymes
Fungi break leaves into pieces; worms release enzymes onto them
Both only move leaves deeper into the soil
12.
Mr Diaz recorded the temperature in the centre of his compost heap each week. Why did it rise again soon after each turning?
Dr Dabour Hub Science Diagram and Course Material
Air got in, so decomposers respired aerobically faster
Turning squeezed water out, so the heap dried and warmed
The Sun heated the new material brought to the surface
Turning killed the microbes, and dead microbes give off heat
13.
After harvest, a farmer ploughs the leftover stems and roots back into the soil. How does this help next year's crop?
Their decay returns mineral ions to the soil
The crop can eat the stems as ready-made food
The old roots keep photosynthesising underground
It stops decomposers from living in the field
14.
Which statement correctly describes decay?
an organism that breaks down dead material
a factor that can change
breakdown of organic matter
a type of fungus
15.
Each option links a process in decay with what it produces. Which pairing is correct?
Digestion by enzymes – large insoluble molecules
Absorption by roots – carbon dioxide in the soil
Respiration by decomposers – carbon dioxide
Photosynthesis by fungi – sugar in the leaf litter
16.
Use the table. Which conclusion is best supported?
The plants ate the compost as their food
Compost works by giving plants extra light
Compost supplied mineral ions that plants took up
Mineral ions have no effect on plant growth
17.
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
18.
Rahul sealed equal masses of three soil samples in flasks with carbon dioxide sensors. Comparing flasks A and C, what can he conclude?
Dr Dabour Hub Science Diagram and Course Material
Soil gives off carbon dioxide even with nothing alive in it
Living microbes in the soil released the carbon dioxide
Heating soil makes it release far more carbon dioxide
Moist soil takes carbon dioxide in from the flask air
19.
The diagram shows a fungal hypha feeding on a dead leaf. Which statement correctly describes arrows P and Q?
Dr Dabour Hub Science Diagram and Course Material
P: carbon dioxide released; Q: oxygen absorbed from the leaf
P: soluble food released; Q: enzymes taken back in
P: enzymes released; Q: small soluble molecules absorbed
P: spores released; Q: water pushed into the leaf
20.
Use the table. Which plot does not fit the pattern, and what is the most likely reason?
Plot A – it had too few earthworms to count
Plot C – decay cannot be that fast in a month
Plot B – mild, damp soil always slows decay
Plot D – the cold slowed the worms and microbes
21.
Each option links a condition that is removed with an everyday way of stopping decay. Which pairing is correct?
Warmth removed – keeping milk in a fridge
Oxygen removed – drying apricots in the sun
Water removed – vacuum packing meat
Microbes killed – shredding grass clippings
22.
Grace buried potato blocks of the same total volume, cut in different ways, in warm moist compost. What best explains her results?
Dr Dabour Hub Science Diagram and Course Material
Smaller pieces contain more water, so microbes drown
Cutting the potato killed microbes inside it
The single block had more food, so it decayed faster
More pieces give more surface for decomposers to act on
23.
Bodies buried long ago in hot, very dry desert sand have been found with skin and hair preserved. Which condition for decay was missing?
Warmth for their enzymes
Light for the decomposers
Water for the microorganisms
Carbon dioxide from the air
24.
Bodies thousands of years old have been found in peat bogs with skin still present. The peat is waterlogged and acidic. Why was decay so slow?
The water in the bog kept the bodies warm enough
Peat contains extra oxygen that protects skin
Bog plants photosynthesised on the bodies
There was little oxygen, and the acid stopped most microbes
25.
Which statement correctly describes mould?
breakdown of organic matter
an organism that breaks down dead material
a factor that can change
a type of fungus
26.
Ecologists placed equal bags of leaf litter in three places and measured how much remained. Which statement is best supported by the graph?
Dr Dabour Hub Science Diagram and Course Material
Decay was fastest where the ground stayed frozen
Decay was fastest where it was warm and wet
Leaves decayed at the same rate in all three places
Tundra leaves did not decay at all over the year
27.
Each option links an observation from a bread-decay investigation with its explanation. Which pairing is correct?
Dry slice had least mould – drying adds food for microbes
Slice at 4 °C had least mould – enzymes worked slowly in the cold
Slice at 25 °C had most mould – warmth kills the microbes
Sealed slice grew mould – mould appears from nowhere
28.
Which step comes immediately after "change one variable"?
state a hypothesis
use results to form a conclusion
measure decay
29.
A poster links organisms with their role in a woodland. Which pairing is correct?
Mushroom – makes food by photosynthesis
Bacterium – large animal that chews leaves
Oak tree – decomposer of dead wood
Earthworm – breaks dead leaves into small pieces
30.
Use the table. About how long would a lettuce stay fresh in a fridge set to 6 °C?
About 3 days
About 7 days
About 10 days
About 12 days
31.
Use the table. Why did sample D turn sour almost as quickly as the raw milk?
Boiling for 5 minutes adds microbes to the milk
Uncovered milk is colder, so it sours faster
New microbes from the air got into the milk
Sample D was boiled for less time than sample C
32.
Which term is described as: an organism that breaks substances down - but it cannot break down DDT?
bioaccumulation
toxic
decomposer
DDT
33.
Which term is described as: a type of fungus?
decay
variable
mould
decomposer
34.
Which term is described as: an organism that breaks down dead material?
decay
mould
variable
decomposer
35.
Which term is described as: a factor that can change?
decay
decomposer
mould
variable
36.
Which term is described as: breakdown of organic matter?
decomposer
variable
decay
mould
37.
Use the leaf litter graph. In the tropical rainforest, half of the leaf mass had decayed after about _____.
Dr Dabour Hub Science Diagram and Course Material
4 months
2 months
8 months
12 months
38.
Decay returns mineral ions such as _____ to the soil for plants to use.
oxygen gas
glucose sugar
nitrates
starch grains
39.
Dead leaves at the bottom of a deep, still lake decay very slowly because the mud there has very little _____.
oxygen gas
liquid water
mineral salts
total darkness
40.
Repeating a decay investigation three times and calculating a mean makes the results more reliable. True or false?
False – repeats always give exactly the same answer
False – a mean hides the real result
True – repeats reduce the effect of odd results
True, but only if the results are all identical
41.
A sandwich forgotten in a warm, closed lunchbox will decay faster than one left to dry out on a sunny windowsill. True or false?
False – sunlight is needed for decay
True – the lunchbox keeps it warm and moist
False – closed boxes contain no microbes at all
True, but only because the box contains extra light
42.
Bread mould is a fungus whose thread-like hyphae spread through the bread as it feeds. True or false?
False – bread mould is a type of bacterium
False – mould is a plant growing on the bread
True – moulds are made of thread-like hyphae
True, but only when the bread is dry
43.
In a sealed jar containing a rotting peach, the percentage of carbon dioxide in the air will rise over several days. True or false?
True – decomposers release it as they respire
False – decay uses up carbon dioxide
False – the peach absorbs all the gas
True, but only if the jar is kept in the dark
44.
Woodlice are decomposers that release enzymes onto dead leaves and absorb the digested food, just as fungi do. True or false?
False – woodlice eat leaves and break them into pieces
True – woodlice feed exactly like fungi do
True – all animals in the soil are decomposers
False – woodlice make their own food from light
45.
Compare flasks A and B on the soil graph. The results suggest that decomposers in soil need water to be fully active. True or false?
Dr Dabour Hub Science Diagram and Course Material
True – the dried soil released far less carbon dioxide
False – the dried soil released the most carbon dioxide
False – water has no effect on any decomposer
True, but only because drying killed every microbe
46.
Use the fence post table. Hana concludes: "Water alone is enough for fast decay." True or false?
False – the wet clay part rotted slowly as it lacked air
True – the wettest part of the post rotted fastest
True – the dry part rotted the most of all
False – the wet clay was simply too warm for decay
47.
Vacuum-packed fish will never decay, even if it is left on a warm shelf for weeks. True or false?
True – no microbe can survive without oxygen
False – it slows most decay, but should still be kept cold
True – vacuum packing kills all the microbes
False – vacuum packing makes decay happen faster
48.
Dried fruit keeps well because drying kills all the microorganisms on it. True or false?
True – drying heats the fruit to boiling point
True – no microbe can survive being dry
False – dried fruit actually spoils faster
False – drying removes the water that microbes need
49.
Honey keeps for years because its very high sugar content draws water out of microbes. True or false?
False – honey keeps because it is very cold
False – sugar is food, so microbes grow faster
True, but only if the honey is kept in a fridge
True – without water, microbes cannot grow
50.
Mineral ions released by decay, such as nitrates, are taken up by plant roots from the soil. True or false?
False – plants take in nitrates through their leaves
True – plants reuse the recycled nutrients
False – decay destroys all the minerals
True, but only for plants that are dead
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Part of Grade 8 - Unit 7: Microorganisms and food webs — see every lesson and quiz in this unit.
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