Question 1

Endosperm is completely consumed by the developing embryo in

Accepted Answer

In pea and groundnut, endosperm is consumed by developing embryo in the seed. The endosperm is completely absorbed by the growing embryo and the food reserve gets stored in the cotyledons. Such seeds are called non-endospermic or exalbuminous.So, the correct option is 'Pea and groundnut'.

Question 2

What is endosperm ? Explain various types of endosperms.

Accepted Answer

Endosperm is a tissue present inside the seeds of most of the angiosperms which appears after fertilization. It provides nutrition to the embryo. In angiosperms, endosperms are of three types:(i) Nuclear type: It is the most common type of endosperm formation. In this type the primary endosperm nucleus gives rise to a number of free nuclei which remain as a peripheral layer and a large central vacuole appears in the embryo sac. Cell wall formation takes later leading to the formation of cellular endosperm. For example, Coconut, Areca.(ii) Cellular type: In it, first division of primary endosperm nucleus is followed by wall formation, hence endosperm is cellular. For example, Datura.(iii) Helobial Type: It is in between the nuclear and cellular types. Wall formation occurs after tThe first division of endosperm nucleus. A large number of nuclei are formed in it by free nuclear divisions. The nucleus of chalazal chamber divides to form free nuclei or may divide at all. For example, Drimya.

Question 3

In the embryos of a typical dicot and a grass, true homologous structures are?

Accepted Answer

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Question 4

If an endosperm cell of an angiosperm contains $24$ chromosomes, the number of chromosomes in each cell of the root will be?

Accepted Answer

In seed plants, the endosperm is the tissue that surrounds and nourishes the embryo.Endosperm is triploid in nature i.e 3n    $3n= 24$  then    $ n= \dfrac{24}{3} = 8$Each cell of the root structure represents the diploid condition in the plants i.e 2n      $2n = 2\times8 = 16$So, the number of chromosome in root cell is 16.

Question 5

When a diploid female plant is crossed with a tetraploid male, the ploidy of endosperm cells in the resulting seed is

Accepted Answer

When the male plant is tetraploid the gamete formed after meiotic division will be will be diploid.The female plant is diploid as a result, the gamete formed after the meiotic division will be haploid.The endosperm cell is formed by the fusion of two polar nuclei and one male gamete.The two polar nuclei means (n+n) =2n and one male gamete = 2n, which fuses to form an endosperm cell = 4n or tetraploid.So, the correct answer is 'Tetraploidy'.

Question 6

A plant has $24$ chromosomes in microspore mother cell. The number of chromosomes in its endosperm will be

Accepted Answer

The inner diploid sporogenous tissue of each microsporangium first undergoes mitotic divisions to increase the cell number and then differentiates into microspore/pollen mother cell. Being the product of mitosis in diploid cells, microspore mother cells are diploid i.e. carry two complete sets of chromosomes. Double fertilization is characterized by fusion of one male gamete fuses with egg nucleus (syngamy) to form the diploid embryo and that of other with diploid secondary nucleus/central cell (triple fusion) to form triploid primary endosperm nucleus which in turn divides to form large nutritive endosperm. This makes endosperm triploid being the product of triple fusion between the diploid secondary nucleus and haploid male gamete. Therefore, if microspore mother cell has 2n= 24 chromosomes, the triploid endosperm will have 3n= 36 chromosomes. Thus, the correct answer is option A.

Question 7

A gymnospermic leaf carries 16 chromosomes. The number of chromosomes in its endosperm is .............................

Accepted Answer

Gymnosperms are characterized by development of endosperm from haploid megaspores before fertilization. Here, the endosperm is gametophytic tissue and is haploid. A gymnopsermic leaf is a somatic organ which has diploid chromosome number in its cell. According to question, the number of chromosomes in leaf is 16 (2n) which means that its haploid chromosome number (the chromosome number present in gametes) is 8 (n). The megaspores, being the product of meiosis in megaspore mother cells (2n), are haploid and therefore chromosome number of its endosperm is n=8. Option A is correct. Since angiospermic endosperm is product of triple fusion, it is triploid; thus angiospermic plant with 2n=16 have endosperm 3n=24. Option D is incorrect. A plant with 2n=16 cannot have endosperm with 12 or 16 chromosomes which are neither haploid nor triploid for it. Options B and C are incorrect. Correct answer is A.

Question 8

Endospermic seeds are found in.

Accepted Answer

Endospermic seeds are those that have an endosperm in the mature seed. It is fleshy, oily, surrounds the embryo, and functions as the sole food storage organ. Inside the seed coat, a thin and papery cotyledon is present. Monocot plants have endospermic seeds.So, the correct option is 'All of these'.

Question 9

The mature seeds of plants such as gram and peas, possess no endosperm, because

Accepted Answer

Gram and pea both are dicot seeds. Cotyledons take up most of the space in the seed and these cotyledons become filled with the material that will nourish the growing embryo. therefore the endosperm is used up by the developing embryo. So, the correct option is endosperm gets used up by the developing embryo during seed development.

Question 10

Non-albuminous seed is produced in?

Accepted Answer

There are two types of seeds - albuminous and non-albuminous seeds. Albuminous seeds have persisted residual endosperm because it is not completely consumed during embryonic development. For example, wheat, castor, maize.Non-albuminous seeds are the seeds that do not have residual endosperm because it is completely consumed during embryonic development. For example, pea, groundnut.So, the correct answer is option D.

Revise with Concepts

Basics of Fertilization and Seed

Embryo in Plants

Fruits and Seeds

Post Fertilization Events and Endosperm

Learn with Videos

Quick Summary With Stories

The Seed

Post fertilization: Embryogenesis in Plants

Post Fertilization Event: Endosperm formation

Parthenocarpy

Endosperm is completely consumed by the developing embryo in

What is endosperm ? Explain various types of endosperms.

In the embryos of a typical dicot and a grass, true homologous structures are?

If an endosperm cell of an angiosperm contains $24$ chromosomes, the number of chromosomes in each cell of the root will be?

When a diploid female plant is crossed with a tetraploid male, the ploidy of endosperm cells in the resulting seed is

A plant has $24$ chromosomes in microspore mother cell. The number of chromosomes in its endosperm will be

A gymnospermic leaf carries 16 chromosomes. The number of chromosomes in its endosperm is .............................

Endospermic seeds are found in.

The mature seeds of plants such as gram and peas, possess no endosperm, because

Non-albuminous seed is produced in?

Revise with Concepts

Basics of Fertilization and Seed

Embryo in Plants

Fruits and Seeds

Post Fertilization Events and Endosperm

Learn with Videos

Quick Summary With Stories

The Seed

Post fertilization: Embryogenesis in Plants

Post Fertilization Event: Endosperm formation

Parthenocarpy

Endosperm is completely consumed by the developing embryo in

What is endosperm ? Explain various types of endosperms.

In the embryos of a typical dicot and a grass, true homologous structures are?

If an endosperm cell of an angiosperm contains 24 chromosomes, the number of chromosomes in each cell of the root will be?

When a diploid female plant is crossed with a tetraploid male, the ploidy of endosperm cells in the resulting seed is

A plant has 24 chromosomes in microspore mother cell. The number of chromosomes in its endosperm will be

A gymnospermic leaf carries 16 chromosomes. The number of chromosomes in its endosperm is .............................

Endospermic seeds are found in.

The mature seeds of plants such as gram and peas, possess no endosperm, because

Non-albuminous seed is produced in?

If an endosperm cell of an angiosperm contains $24$ chromosomes, the number of chromosomes in each cell of the root will be?

A plant has $24$ chromosomes in microspore mother cell. The number of chromosomes in its endosperm will be