NEET Biology Reproduction : Multiple Choice Previous Years Questions MCQs 3

TL;DR

This video discusses various aspects of plant reproduction, including the structure of the embryo sac, types of seeds, and the association between flowers and pollinating agents.

Transcript

hello friends this video on meat reproduction is brought to you by exam co calm normal pure from exam question number 16 which one of the following pairs of plant structures has haploid number of chromosomes megaspore mother cell and antipodal cells egg cell and antipodal cells new sellers and antipodal cells egg nucleus and secondary nucleus okay ... Read More

Key Insights

• 🥺 Megaspore mother cells undergo meiosis to produce haploid megaspores, leading to the formation of the embryo sac with eight haploid nuclei.
• 🖤 Non-endosperm seeds lack endosperm because it is already consumed by the developing embryo.
• 🧑‍🏭 The kalos wall acts as a temporary barrier in microspore mother cells to prevent cohesion and fusion of the spores.
• 🍆 Dicot plants have a specific arrangement of nuclei within the normal embryo sac: 3 antipodal cells, 2 polar nuclei, and 3 cells in the egg apparatus.

Questions & Answers

Q: What is the function of the megaspore mother cell in plant reproduction?

The megaspore mother cell undergoes meiosis to produce four haploid megaspores, one of which survives to form the embryo sac.

Q: Which seeds lack endosperm at maturity?

Non-endosperm seeds lack endosperm because it is consumed by the developing embryo. Examples include peas and beans.

Q: What is the purpose of the kalos wall in microspore mother cells?

The kalos wall acts as a temporary barrier to prevent the spores from sticking together or fusing during meiosis, ensuring their separation.

Q: How are the nuclei arranged in a normal dicot embryo sac?

The arrangement is 3 antipodal cells, 2 polar nuclei, and 3 cells in the egg apparatus, totaling 8 haploid nuclei.

Q: Which type of ovule has the micropyle directed downward?

Anatropous ovules have a downward-facing micropyle due to their fully inverted structure.

Summary & Key Takeaways

• The megaspore mother cell is not haploid, but it undergoes meiosis to form four haploid megaspores. Only one survives and undergoes mitosis to form eight haploid nuclei in the embryo sac.

• Non-endosperm seeds are those in which the endosperm is consumed by the developing embryo, such as coconuts and castor beans.

• The microspore mother cell is surrounded by a temporary wall called the kalos, which prevents the spores from sticking together.

• In dicot plants, the arrangement of nuclei in the normal embryo sac is 3 antipodal cells, 2 polar nuclei, and 3 cells in the egg apparatus.

• Hemi-anatropous ovules are curved at a 90-degree angle, while anatropous ovules are fully inverted.