CIE iGCSE Co-Ordinated Science B12. Respiration Exam Style Questions Paper 4
Question
(a) A student monitors their heart rate during vigorous exercise for 30 minutes.
Their heart rate is measured in beats per minute (bpm).
Fig. 4.1 is a graph of the results.
Complete the sentences to describe and explain the results in Fig. 4.1.
During exercise, the heart rate increases to a maximum of ……………………………………… bpm.
Heart rate increases because the body requires more energy for
muscular ……………………………………… .
Energy is released by the process of aerobic respiration.
The oxygen required for aerobic respiration is transported by ……………………………………… in red blood cells.
(b) Complete the balanced chemical equation for aerobic respiration.
……………………….. + …….O$_{2→}$ ……………………….. + ………………………..
(c) During vigorous exercise energy is also released by anaerobic respiration.
Describe two disadvantages of anaerobic respiration.
(d) Blood is transported by blood vessels.
(i) Explain why veins in the legs have valves but arteries in the legs do not have valves.
(ii) State the name of the main artery that transports blood away from the heart.
(e) Plants have specialised transport vessels.
State the name of two plant vessels specialised for transport.
▶️Answer/Explanation
Ans : 4(a) 190 ;
contraction ;
haemoglobin ;
4(b) C$_{6}$H$_{12}$O6 + 6O$_{2}$ → 6CO$_{2}$ + 6H$_{2}$O
one mark for correctly balanced reactants ;
one mark for correctly balanced products (either order) ;
4(c) releases (much) less energy (per glucose molecule than aerobic respiration) ;
produces lactic acid / causes an oxygen debt ;
4(d)(i) transport blood under low(er) pressure ;
(valves) ensure one-way flow of blood / AW ;
4(d)(ii) aorta ;
4(e) xylem ;
phloem ;