DNA, genes and the genomeIB MYP Biology: Mind map

Exam questions on DNA, genes and the genome

1. A science museum in Dubai has built a large model of DNA for visitors to explore. The model shows two long strands twisted around each other, with the strands joined together in the middle by pairs of bases.
   Distinguish between a gene and the genome.2 marks
2. A student in Manila extracts DNA from strawberries in a school laboratory. She mashes the fruit, adds a mixture of salt and washing-up liquid, filters it, and then carefully pours ice-cold ethanol on top of the filtered liquid. White, stringy strands slowly appear where the two liquids meet.
   Explain why the student mashes the fruit and then filters the mixture.2 marks
3. A genetic counsellor in Cape Town explains to a family that every human body cell has a nucleus containing chromosomes made of DNA, and that a change in a gene can sometimes cause an inherited disorder.
   State the number of chromosomes in a human body cell and describe how chromosomes, genes and DNA are related.3 marks