1. 1
   A student is investigating two ways that strawberry plants can produce new plants: growing new plants from seeds after pollination, and growing identical new plants from runners sent out by the parent plant.

   (a)

   Which process produces the runners?

   [1 mark]

   • ASexual reproduction involving the fusion of gametes
   • BAsexual reproduction by mitosis
   • CMeiosis producing four gametes
   • DFertilisation of a pollen cell

   (b)

   Compared with reproduction from seeds, offspring produced from runners are

   [1 mark]

   • Agenetically identical to the parent plant
   • Bgenetically identical to each other but different from the parent
   • Cmore genetically varied than seed-grown offspring
   • Dformed by the fusion of two gametes

   (c)

   Suggest one advantage to a strawberry grower of producing new plants from runners rather than from seeds, and one advantage of producing new plants from seeds rather than from runners.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A biology class is studying how sperm cells are produced in the testes of a human male. Body cells in the testes contain the normal (diploid) number of chromosomes for a human.

   (a)

   How many gametes are produced from one starting cell during meiosis?

   [1 mark]

   • A1
   • B2
   • C4
   • D8

   (b)

   What happens to the chromosome number when two gametes fuse at fertilisation?

   [1 mark]

   • AIt is halved compared with the body cells
   • BIt is doubled compared with the gametes but remains half the body cell number
   • CIt stays the same as the number in each gamete
   • DIt is restored to the normal body cell number

   (c)

   Explain why the four sperm cells produced from a single starting cell by meiosis are all genetically different from each other.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A researcher is studying a short section of human chromosome 7 that contains a gene linked to a genetic disorder, as part of the wider project to study the entire human genome.

   (a)

   Describe the structure of DNA.

   [3 marks]

   (b)

   Define what is meant by a gene and by a genome, and explain why studying the entire human genome is useful to medicine.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A plant breeder is trying to increase the population of a rare orchid species that is at risk of extinction. The breeder can propagate new orchids either by growing them from seeds produced after pollination, or by taking cuttings from an existing plant (asexual reproduction). The breeder also wants to understand how a single mutation in one gene could affect the appearance of the orchid's flowers.

   (a)

   Evaluate whether the breeder should propagate the rare orchid using seeds or using cuttings, using your knowledge of sexual and asexual reproduction.

   [6 marks]

   (b)

   Explain, using your knowledge of DNA structure and protein synthesis, how a mutation in a single gene could change the appearance of the orchid's flowers.

   [6 marks]

   Total for question 4: 12 marks

End of questions