The passage describes the nucleus of a cell with missing words replaced by the letters J, K, L and M. Read the passage, then select words from the list below the passage to replace letters J, K, L and M. In the nucleus of a body cell from a person with Down's syndrome, there are J thread-like structures called K. These are made up of many units called L that instruct the cell to produce a particular M. carbohydrate fat protein chromosomes forty-seven twenty-four DNA genes twenty-three J K L M

1. (a)The passage describes the nucleus of a cell with missing words replaced by the letters J, K, L and M. Read the passage, then select words from the list below the passage to replace letters J, K, L and M. In the nucleus of a body cell from a person with Down's syndrome, there are J thread-like structures called K. These are made up of many units called L that instruct the cell to produce a particular M. carbohydrate fat protein chromosomes forty-seven twenty-four DNA genes twenty-three J K L M[4]
2. (b)When suddenly exposed to bright light, some people automatically sneeze. This is known as the photic sneeze reflex. The photic sneeze reflex is the result of the possession of a dominant allele A. Use a genetic diagram to show how parents, both with the photic sneeze reflex, can have a child who is not affected by the photic sneeze reflex.[3]