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Reproduction in Plants - Sexual Reproduction and Parts of a Flower

Grade 7CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Sexual reproduction involves the fusion of male and female gametes to produce a new individual, ensuring genetic variation.

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The flower is the reproductive organ of the plant. A flower may be unisexual (e.g., papaya, corn) or bisexual (e.g., rose, mustard).

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The male reproductive part is the Stamen, which consists of the anther and the filament. The anther contains pollen grains that produce male gametes.

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The female reproductive part is the Pistil (or carpel), consisting of the stigma, style, and ovary. The ovary contains ovules, where the female gamete or egg is formed.

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Pollination is the transfer of pollen grains from the anther to the stigma. It can be self-pollination (within the same flower) or cross-pollination (between different flowers of the same kind).

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Fertilization is the process where the male gamete fuses with the female gamete to form a single-celled ZygoteZygote.

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After fertilization, the ovary grows into a fruit, and the ovules develop into seeds. The seeds contain the embryo, which is a result of the ZygoteZygote dividing.

📐Formulae

Male Gamete+Female Gamete→FertilizationZygoteMale\ Gamete + Female\ Gamete \xrightarrow{Fertilization} Zygote

Ovary→Post−fertilizationFruitOvary \xrightarrow{Post-fertilization} Fruit

Ovule→Post−fertilizationSeedOvule \xrightarrow{Post-fertilization} Seed

💡Examples

Problem 1:

A pollen grain lands on the stigma of a flower. Describe the process that leads to the formation of a ZygoteZygote.

Solution:

  1. Pollen grain germinates on the stigma. 2. A pollen tube grows through the style to reach the ovary. 3. The male gamete travels through the tube. 4. Fusion of male and female gametes occurs in the ovule: Male Gamete+Female Gamete=ZygoteMale\ Gamete + Female\ Gamete = Zygote.

Explanation:

This process is called fertilization. The pollen tube acts as a conduit for the male gamete to reach the egg inside the ovule.

Problem 2:

Identify the biological 'product' and 'container' in a mango after the process of sexual reproduction.

Solution:

The 'container' is the ripened ovary, which becomes the Fruit (MangoMango). The 'product' inside is the developed ovule, which becomes the SeedSeed.

Explanation:

In angiosperms (flowering plants), the ovary walls thicken and ripen to protect the seeds, which contain the embryo for the next generation.