10.1 Meiosis

1.Which structure found in eukaryotes has a single membrane?

2. Which gametes can result from the following crossover?

3. The genetic determination of dogs’ coats can be quite complex, with many different genes acting at the same time.

• The dominant allele E gives brown tones. The recessive allele e results in red tones. • The colour intensity is due to another gene. The dominant allele B gives a dark colour, whereas the recessive allele b results in a light colour.

What would be the genotype of a light brown dog produced from a cross between a dark brown dog and a light red dog?

4. In which situation are alleles exchanged?

5. During which stage of meiosis does crossing over usually occur?

6. At which stage of meiosis does a pair of sister chromatids separate?

7. How does meiosis cause Mendel’s law of independent assortment?

8. Maize (Zea mays) contains 20 chromosomes in a diploid cell. How many chromosomes will be in each cell after the first and second division of meiosis?

9. When does an unequal division of cytoplasm occur?

10. What happens in crossing over?

11. The diagram below shows chromosomes during meiosis. How many chromosomes and chiasmata are visible?

12. How many autosomes are there in a human sperm?

13. When do chiasmata form in meiosis?

14. Which of the following conclusions did Mendel make from his experiments?