Sex Determination Systems

20 questions • 1 test • tap a section to begin

Welcome! 2.1 Sex Determination Systems — Test 1 — 20 questions, CSIR-NET style.

What this test covers

  • Chromosomal systems: XY, ZW, XO, X:A ratio
  • Drosophila X:A ratio, Sxl, intersexes
  • SRY & the mammalian Y chromosome
  • Holandric (Y-linked) genes

How to use

  • Tap the test below — it opens on its own full screen. Use ← All tests at the top to come back.
  • Each question has a 40-second timer. Answer, then Submit to see your score.
  • Tap 📋 View Solution under any question for a full explanation.

Open Review at the bottom for a quick revision list of every question with its correct answer.

Quiz
Question Palette
Quiz
Question Palette
Quiz
Explanation:

Quick revision: every question with its correct answer. For the full explanation, open the test and tap View Solution.

2.1 Sex Determination Systems — Test 1
Q1. The pattern of chromosomal sex determination in birds is:✓ ZW–ZZ
Q2. Which animal has a ZZ/ZW sex-determination system?✓ Chicken
Q3. In birds, butterflies and moths, the sex-determination mechanism is:✓ ZZ–ZW
Q4. Which is an example of heterogametic females?✓ Moths
Q5. In Drosophila melanogaster, sex is determined by:✓ The X:autosome (X/A) ratio
Q6. The sex index (X:A ratio) in Drosophila relates to sex determination because it reflects:✓ Activity of female-determining genes on the X balanced against male-determiners on autosomes
Q7. The Sex-lethal (Sxl) gene in Drosophila is transcribed (turned on) when:✓ X:A balance is 1 or greater
Q8. A Drosophila with an X:A ratio of 0.75 would be:✓ Inter-sex
Q9. The sex of a fruit fly with 4 X chromosomes and 4 sets of autosomes is:✓ Female
Q10. The phenotype of a fruit fly with XXYYY sex chromosomes and two sets of autosomes is:✓ Female
Q11. In Drosophila XXY is female, but in humans XXY is an abnormal male, because:✓ The Y induces male traits in humans
Q12. The male-determining gene on the Y chromosome that organises the gonad into a testis is:✓ SRY
Q13. The SRY gene product is best described as a:✓ DNA-binding protein expressed in the genital ridge
Q14. Which gene is NOT located on the Y chromosome and not directly related to vertebrate sex determination?✓ sox9
Q15. The Y chromosome in mammals is:✓ Non-essential for development but important for male sex determination
Q16. Holandric genes are located on the:✓ Y chromosome
Q17. Holandric (Y-linked) genes are inherited:✓ Father to son only
Q18. The hypertrichosis (hairy ear rims) trait is present on the:✓ Holandric (Y) chromosome
Q19. Hypertrichosis is Y-linked. If an affected man marries a normal woman, the offspring will be:✓ All sons affected, none of the daughters
Q20. Match each organism/condition with its sex-determination basis and select the correct option.✓ A-ii, B-iv, C-i, D-iii