10 questions ยท Form 5 Biology Bab 6: Sexual Reproduction in Flowering Plants
Which of the following structures constitutes the female reproductive organ (gynoecium / pistil)?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. Which of the following structures constitutes the female reproductive organ (gynoecium / pistil)?
Answer: B
The gynoecium (pistil/carpel) consists of the sticky stigma, elongated style, and basal ovary containing ovules.
2. What term describes the transfer of pollen grains from the anther of one flower to the stigma of a flower on a different plant of the same species?
Answer: B
Cross-pollination involves pollen transfer between flowers on different individual plants of the same species, increasing genetic variation.
3. What role do synergid cells play in the female gametophyte?
Answer: B
Synergids flank the egg cell at the micropylar opening and guide the pollen tube toward the embryo sac using chemical attractants.
4. What is the function of the endosperm tissue in seeds?
Answer: B
The triploid endosperm stores essential nutrients (carbohydrates, proteins, fats) to feed the developing plant embryo.
5. Through which microscopic pore in the ovule integuments does the pollen tube enter the embryo sac?
Answer: B
The micropyle is the small opening in the ovule's protective integuments through which the pollen tube enters.
6. How many functional megaspores survive from the four produced by meiosis of a megaspore mother cell?
Answer: A
Meiosis yields four haploid megaspores, but three degenerate, leaving only one functional megaspore to develop into the embryo sac.
7. What ploidy level is the endosperm nucleus formed during double fertilization in flowering plants?
Answer: C
The triploid (3n) endosperm nucleus is formed when one haploid male gamete (n) fuses with two polar nuclei (2n) in the central cell.
8. Which structural component of a pollen grain consists of a tough, sculpted outer layer resistant to decay?
Answer: B
The exine is the tough, highly resistant outer wall composed of sporopollenin that protects pollen grains from harsh environmental conditions.
9. How many total nuclear mitotic divisions occur within the functional megaspore during embryo sac formation?
Answer: C
The functional megaspore undergoes three consecutive mitotic nuclear divisions without immediate cytokinesis, producing $23 = 8$ haploid nuclei.
10. What is the primary function of the tube nucleus inside a germinating pollen grain?
Answer: B
The tube nucleus directs growth of the pollen tube toward the ovule by controlling the secretion of digestive enzymes.