Aerobic respiration overviewEdexcel A-Level Biology B: Mind map

Exam questions on Aerobic respiration overview

1. A hummingbird hovers in front of a flower, beating its wings about 50 times each second. Its flight muscle cells contain very large numbers of mitochondria, and the bird feeds on nectar that is rich in sugar.
   Explain why the flight muscle cells contain very large numbers of mitochondria.2 marks
2. A student places 50 germinating pea seeds in an insulated flask in a dark cupboard and records the temperature each day. A second, identical flask contains boiled peas that cannot respire. After three days the temperature in the first flask has risen from 20.0 °C to 26.5 °C, while the second flask stays at 20.0 °C.
   Explain why the temperature in the first flask rose, using ideas about the transfer of energy in respiration.2 marks
3. A researcher breaks open liver cells and separates the contents into two fractions: the cytoplasm, and the mitochondria. She sets up two tubes in aerated solution. Tube 1 contains only the cytoplasm fraction, glucose, ADP, phosphate and NAD. Tube 2 contains only the mitochondria fraction, pyruvate, ADP, phosphate and NAD.
   Predict and explain what products will be formed in tube 1 after incubation.3 marks