Quick revision: every question with its correct answer. For the full explanation, open the test and tap View Solution.
2.5 Sex Determination, SRY & X-Linked Inheritance โ Test 2
Q1. Chromosomes that are NOT involved in sex determination are called:โ Autosomes
Q2. In humans, the sex chromosomes are:โ The X and Y chromosomes
Q3. The master sex-determining gene SRY is located on the:โ Y chromosome
Q4. In birds, the male is the homogametic sex, with sex chromosomes:โ ZZ
Q5. In Drosophila, sex is determined by the ratio of:โ X chromosomes to autosome sets (X:A ratio)
Q6. In the honey bee, males develop from unfertilised eggs (haploid) and females from fertilised eggs (diploid). This system is called:โ Haplodiploidy
Q7. Dosage compensation in mammals is achieved by:โ Inactivating one X chromosome in females
Q8. The number of Barr bodies in a cell equals:โ The number of X chromosomes minus one
Q9. X-linked recessive traits are typically:โ More common in males than females
Q10. A colour-blind man marries a woman who is a carrier for colour blindness. The expected proportion of their children who are colour blind is:โ 50%
Q11. An observation that effectively rules out X-linked recessive inheritance of a trait in a pedigree is:โ Male-to-male (father-to-son) transmission
Q12. A gene located on the Y chromosome (transmitted father to son only) shows ___ inheritance:โ Holandric (Y-linked)
Q13. A carrier mother (for an X-linked recessive disease) and an unaffected father have children. The proportion of affected sons is:โ 1/2 (half of sons)
Q14. The heterogametic sex is the one that:โ Produces two kinds of gametes with respect to sex chromosomes
Q15. The inactivated X chromosome in a female somatic cell is condensed as the:โ Barr body
Q16. X-inactivation in a given cell is:โ Random (either X may be inactivated)
Q17. In an XX/XO sex-determination system (e.g. some insects), the males are:โ XO (single X, no second sex chromosome)
Q18. Genes in the pseudoautosomal regions of the X and Y chromosomes are notable because they:โ Are present on both X and Y and can recombine between them
Q19. Criss-cross inheritance (an affected grandfather passing a trait to his grandsons via carrier daughters) is typical of:โ X-linked recessive traits
Q20. Match each system/term with its description and select the correct option.โ A-ii, B-iii, C-iv, D-i