NUMS — Medical & Dental Entry Test
Take the NUMS Biology — Reproduction, Inheritance, Evolution and Biotechnology (Set 2): 30 multiple-choice questions (40 minutes) with instant scoring and…
What this test covers
The first 5 questions of this test, with the correct answer and explanation.
Q1. Sperm are stored and gain the ability to swim while passing through the:
Answer: B. Epididymis
Explanation: Sperm made in the seminiferous tubules mature and become motile during their passage through the coiled epididymis.
Q2. The testes hang outside the abdomen in the scrotum because:
Answer: B. Sperm production needs a temperature about 2–3 °C below core body temperature
Explanation: Spermatogenesis is most efficient slightly below body temperature; undescended testes can cause infertility.
Q3. Sertoli cells in the seminiferous tubules are important because they:
Answer: D. Nourish developing sperm cells and respond to FSH
Explanation: Sertoli (nurse) cells support and nourish spermatogenic cells under FSH stimulation; Leydig cells make testosterone.
Q4. A human primary oocyte has 46 chromosomes. How many chromosomes does a secondary oocyte have?
Answer: A. 23
Explanation: The first meiotic division halves the chromosome number, so the secondary oocyte and first polar body each have 23 chromosomes.
Q5. A woman's blood shows high oestrogen, low progesterone and rising LH. She is most likely at which stage of the cycle?
Answer: A. Just before ovulation
Explanation: Rising oestrogen from the maturing follicle triggers the LH surge just before ovulation; progesterone rises only after ovulation from the corpus luteum.
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Q6. Combined contraceptive pills contain oestrogen and progesterone. They prevent pregnancy mainly by:
Q7. Couples with blocked fallopian tubes may be helped by in-vitro fertilisation (IVF). In IVF, the step that replaces the tube's natural role is:
Q8. After one sperm enters the egg, the zona pellucida hardens. The importance of this is to:
Q9. The placenta allows exchange between mother and fetus but normally prevents:
Q10. In a flowering plant, the endosperm cells of a seed contain 36 chromosomes. How many chromosomes are in the plant's leaf cells?
Q11. Two black guinea pigs produce some white offspring. If black (B) is dominant, the genotypes of the parents must be:
Q12. A tall pea plant is crossed with a dwarf plant and gives 48 tall and 52 dwarf offspring. The tall parent's genotype was:
Q13. In a dihybrid cross AaBb × aabb (genes unlinked), what proportion of offspring show both recessive traits?
Q14. In cattle, a red bull (RR) mated with a white cow (WW) produces roan calves with both red and white hairs. This illustrates:
Q15. A child has blood group O. The mother is group A. Which blood group could the father NOT have?
Q16. Haemolytic disease of the newborn may occur in a second pregnancy when:
Q17. A colour-blind man marries a woman with normal vision whose father was colour-blind. What is the probability that their daughter is colour-blind?
Q18. In humans, the sex of a baby is determined by:
Q19. A person with karyotype 45, X (one X chromosome and no Y) has:
Q20. During transcription, the enzyme RNA polymerase synthesises:
Q21. A segment of the DNA template strand reads 3′-TAC GGA-5′. Which amino acids are coded by the resulting mRNA codons, given AUG = methionine and CCU = proline?
Q22. A point mutation changes a codon from GAA to GAG; both code for glutamic acid. This is called a:
Q23. In gene cloning, bacteria that have taken up a plasmid are often identified by growing them on a medium containing an antibiotic. This works because:
Q24. A restriction enzyme cuts a circular plasmid at 3 sites. How many DNA fragments are produced?
Q25. Restriction enzymes that produce 'sticky ends' are preferred in recombinant DNA work because sticky ends:
Q26. DNA fingerprinting is used in forensic science because:
Q27. Bt cotton is resistant to insect pests because it contains a gene from Bacillus thuringiensis that codes for:
Q28. In a population in Hardy–Weinberg equilibrium, 16% of individuals show a recessive phenotype. What percentage are heterozygous carriers?
Q29. A small group of birds colonises an island and, by chance, carries only a few of the alleles of the mainland population. This is an example of:
Q30. The human appendix and the tiny pelvic bones in whales are examples of: