Why do you think the zygote is dormant for sometime in a fertilized ovule?
Solution and Explanation
The zygote is formed by the fusion of male gamete with the nucleus of the egg cell. The zygote remains dormant for some time and waits for the endosperm to form, which develops from the primary endosperm cell resulting from triple fusion. The endosperm provides food for the growing embryo and after the and after the endosperm, further development of the embryo from the zygote starts.
Top Questions on sexual reproduction in flowering plants
Student to attempt either option (A) or (B).
(A)
(i) Describe the process of megasporogenesis in an angiosperm.
(ii) Draw a diagram of a mature embryo sac of the angiosperm. Label its any four parts.
OR
(B) The reproductive cycle in the female primates is called menstrual cycle. The first menstruation begins at puberty.
Answer the following questions:
(i) Name the four phases of menstrual cycle in a proper sequence.
(ii) How long does the menstrual phase last in a menstrual cycle?
(iii) When and why hormones estrogen and progesterone reach their peak levels respectively, in the menstrual cycle?
(iv) Give the significance of LH surge.- CBSE CLASS XII - 2025
- Biology
- sexual reproduction in flowering plants
Flowering plants with hermaphrodite flowers have developed many reproductive strategies to ensure cross-pollination. Study the given outbreeding devices adopted by certain flowering plants and answer the questions that follow.
Note : All plants belong to the same species. No pollen tube growth/inhibition of pollen germination on stigma. Pollen germination on stigma.- [(a)] Name and define the outbreeding device described in the above table.
- [(b)] Explain what would have been the disadvantage to the plant in the absence of the given strategy.
- CBSE CLASS XII - 2025
- Biology
- sexual reproduction in flowering plants
Answer the following questions:
[(i)] Explain the structure of a mature embryo sac of a typical flowering plant.
[(ii)] How is triple fusion achieved in these plants?
OR
[(i)] Describe the changes in the ovary and the uterus as induced by the changes in the level of pituitary and ovarian hormones during menstrual cycle in a human female.
- CBSE CLASS XII - 2025
- Biology
- sexual reproduction in flowering plants
- What are the significances of double fertilization?
- Maharashtra Class XII - 2025
- Biology
- sexual reproduction in flowering plants
- How many meiotic divisions are required for the formation of 300 seeds in angiosperm?
- Maharashtra Class XII - 2025
- Biology
- sexual reproduction in flowering plants
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- CBSE CLASS XII - 2025
- Global Economy
- Draft an invitation card on behalf of the Principal of J.B. Bhatia Public School for the launch of ‘Yoga for Life’ programme in the school. Mention a compelling highlight of the programme along with other necessary details.
- CBSE CLASS XII - 2025
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- A convex lens of focal length \( f = 15\,cm \) forms a real image of a 6 cm tall object placed at 30 cm. Find the position, nature, and height of the image.
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- CBSE CLASS XII - 2025
- Electrostatics
- Define a wavefront. An incident plane wave falls on a convex lens and gets refracted through it. Draw a diagram to show the incident and refracted wavefront.
- CBSE CLASS XII - 2025
- Wave Optics
Concepts Used:
Pollination and Double Fertilization
Pollination is defined as the pre-fertilization event or process, where pollen grains from another are transferred to the stigma of a flower.
Double fertilization is a complex process that involves the fusion of one female gametophyte with two male gametes.
Types of Pollination:
All plants having flowers completely rely on the pollination method for reproduction. There are 2 types of pollination –
- Self Pollination
- Cross-Pollination
The end products of double fertilization are:
- Diploid Zygote
- Primary Endosperm Nucleus