Exam Questions Unit 2- 3

Question 1

How does meiosis produce genetic variation in gametes? (3)

Answer 1

• Independant assortment and crossing over
• Independant assortment gives rise to new combinations of paternal and maternal chromosomes
• crossing over involves swapping of sections of chromatids

Question 2

Why can offspring (twins) be genetically different even though they are from the same father and mother? (3)

Answer 2

• because each zygote is formed from different gametes, through random fertilisation
• each gamete contains different combinations of alleles
• due to independant assortment and crossing over during meiosis