CAIE IGCSE Biology 12 Respiration
Practise energy uses, aerobic and anaerobic equations, oxygen debt and respiration-rate calculations from data.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Covered syllabus points
12. Respiration question 1
Fig. 6.1 shows some cells from the shoot tip of an onion, Allium cepa.
Fig. 6.1
The area labelled M is a mitochondrion.
Explain why mitochondria have an important role in dividing cells.
12. Respiration question 2
Fig. 1.1 shows the movement of particles through an epithelial cell in the small intestine.
Fig. 1.1
Carbon dioxide molecules also move by diffusion.
State the name of the process in human cells that produces carbon dioxide.
12. Respiration question 3
Which statement about both aerobic and anaerobic respiration is correct?
A
They break down .
B
They produce an oxygen debt.
C
They use .
D
They use .
12. Respiration question 4
Question (a)
(a)
Fig. 4.1 is a flow chart showing some of the processes that occur in a biofuels power plant.
Fig. 4.1
[ 2 ]
Question (i)
(i)
The fermentation stage shown in Fig. 4.1 requires yeast.
Complete the balanced chemical equation to show how ethanol is produced by yeast respiration.
[ 2 ]
Question (b)
(b)
One problem with using biomass in the process shown in Fig. 4.1 is that the breakdown stage produces a sugar called xylose and ethanoic acid. Yeast cannot use xylose, and ethanoic acid is toxic to yeast.
Scientists genetically engineered a type of yeast that can use xylose and ethanoic acid.
Fig. 4.2 shows the results of one of the trial experiments done by the scientists using their new genetically engineered yeast.
Fig. 4.2
[ 1 ]
Question (i)
(i)
The experiment was done at .
The scientists repeated the experiment at .
Predict the results that you would expect for the concentration of ethanol.
[ 1 ]
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