Aerobic respirationIB MYP Biology: Mind map

Exam questions on Aerobic respiration

1. During a marathon in Nairobi, a runner's leg muscles release energy by aerobic respiration. As the race goes on, her breathing rate and heart rate both rise.
   Explain why the runner's breathing rate increases during the race.2 marks
2. A hummingbird in Costa Rica beats its wings about 50 times every second and keeps its body at around 40 °C. It feeds on sugar-rich nectar, and its flight muscle cells contain a very large number of mitochondria.
   Explain why the hummingbird's flight muscle cells need a very large number of mitochondria.2 marks
3. A student wants to show that living seeds release energy. She puts 100 g of germinating pea seeds in one vacuum flask and 100 g of boiled (dead) pea seeds in a second flask of the same size. Each flask has a thermometer in a cotton-wool stopper. Both start at 20.0 °C. After 24 hours the flask of germinating peas reads 27.0 °C and the flask of boiled peas reads 20.5 °C.
   Identify the independent variable, the dependent variable and one control variable in this investigation.3 marks