28 9 When astronauts are in space, the force of gravity is less than when they are on a planet such as Earth or Mars. Scientists need to investigate how varying gravity affects astronauts. NASA/Science photo library In one investigation, scientists grew human muscle cells in culture. These cells were split into two groups:  Group 1 was taken into space for 10 days  Group 2 remained on Earth for 10 days. Data were collected on protein synthesis and protein breakdown in each group of cells. (a) State why data were collected for Group 2 as well as for Group 1. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 29 (b) The scientists proposed a null hypothesis for the rate of breakdown of protein in the muscle cells of the two groups. The data from this investigation showed that there was no significant difference at the 0.05 probability level. (i) Explain what is meant by no significant difference at the 0.05 probability level for the rate of breakdown of protein. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Some of the myosin in the muscle cells was broken down. Describe how the tertiary structure of myosin is related to its function. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 30 *(c) Data for the rate of protein synthesis were collected for the groups of muscle cells as shown in the table. Group of muscle cells Mean rate of protein synthesis / arbitrary units Group 1 cells during the 10-day space mission 40 Group 1 cells after the 10-day space mission returned to Earth 380 Group 2 cells 190 It has been estimated that astronauts will travel to Mars by 2030. It will take about nine months to travel from Earth to Mars. The force of gravity is less on Mars than it is on Earth, but greater than it is in space. Discuss the potential effects of gravity on the muscles of astronauts when travelling to Mars and then living on Mars. (6) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 31 .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 9 = 12 marks)