Tag: structure of ovule

Questions Related to structure of ovule

Ovules of Capsella and Pisum sativum are

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Orthotropous

  2. Anatropous

  3. Amphitropous

  4. Campylotropus

Show answer
Correct Option: D
Explanation:

• Orthotropous ovule - The simplest and primitive type of ovule. In this type of ovule, micropyle, chalaza, and funiculus lie in one vertical plane. Examples: all gymnosperms, Polygonum.

• Anatropous ovule - The most common type of ovules which occurs in more than 80% of angiosperm families. The body of ovule is rotated by 180° and micropyle comes near to the funiculus. Chalaza and micropyle lie in the straight line but hilum is at 90° to the micropyle.
• Amphitropous ovule - The body of ovule gets curved along with the embryo sac in such a way that it becomes horseshoe-shaped. This type of ovule is found in families like Butamaceae, Loganiaceae.
• Campylotropous ovule - This type of ovule is similar to Anatropous ovule but the curvature is less than that of an anatropous ovule. The campylotropous ovule is found in family Chenopodiaceae and in Pisum and Capsella.
So, the correct answer is D.

Tetrad of megaspores is generally

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Tetrahedral

  2. Linear

  3. Decussate

  4. Isobilateral

Show answer
Correct Option: B
Explanation:
Megaspore mother cell undergoes meiosis to form four haploid megaspores. These megaspores are arranged in the form of a linear tetrad. The megaspore mother cell undergoes first meiotic division and a transverse wall is laid down resulting in the formation of a dyad. The two cells of the dyad similar divides transversely resulting in the formation of a linear tetrad. Tetrahedral, decussate, and isobilateral tetrads are found in case of microspores i.e. such tetrads are formed during microsporogenesis. Hence, tetrad of megaspores is generally linear.
So, the correct answer is B.

Ovule of Opuntia is

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Campylotropus

  2. Amphitropous

  3. Circinotropous

  4. Hemitropous

Show answer
Correct Option: C
Explanation:
•Campylotropous ovule- This type of ovule is similar to Anatropous ovule but curvature is less than that of anatropous ovule. Micropyle is near to the funiculus. Chalaza and micropyle lie in the straight line but hilum is at 90° to micropyle. Campylotropous ovule is found in family Chenopodiaceae and in Pisum and Capsella.
•Amphitropous ovule- The body of ovule gets curved along with the embryo sac in such a way that it becomes horseshoe-shaped. This type of ovule is found in families like Butamaceae, Loganiaceae.
•Circinotropous ovule- In this type of ovule, the length of funiculus becomes increased and it covers the whole ovule. It is found in families like Cactaceae (Opuntia).
•Hemianatropous ovule- The body of ovule is turned through 90° and micropyle and chalaza lie in a straight line but funiculus is at right angle or 90° with both these two. E.g. Ranunculaceae.
Since Opuntia has Circinotropous ovule.
So, the correct answer is C.

The placenta is attached to the developing seed near the

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Testa

  2. Hilum

  3. Micropyle

  4. Chalaza

Show answer
Correct Option: B
Explanation:

The placenta is attached to the developing seed near hilum. It is the scar located nearthe edge where seed breaks from stalk of funiculus, i.e., connecting the seed with fruitwall and placenta. 


Rest of the options are incorrect as Testa is the outer most covering of seed, micropyle is a small opening in seed coatthrough which water enters seed and chalaza is a tissue where nucellus and integument are joined. Nutrients from the plant travel through vascular tissue in the funiculus and outer integuments through the chalaza into the nucellus. 

Which of the following pairs of terms is a correct match?

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Ovule-egg

  2. Pollen grain-sperm

  3. Seed-zygote

  4. Embryo sac-female gametophyte

  5. All of the above

Show answer
Correct Option: E
Explanation:

Ovule- The ovule is the structure that gives rise to and contains the female reproductive cells. The ovule is located inside the portion of the flower called the gynoecium.

Pollen grain- A pollen grain is a microscopic body that contains the male reproductive cell of a plant. Pollen grains represent the male portion of the reproductive process in plants and trees.
Seed- A seed is an embryonic plant enclosed in a protective outer covering. The embryo is developed from the zygote and the seed coat from the integuments of the ovule.
Embryo sac- the female gametophyte of a seed plant consisting of a thin-walled sac within the nucellus that contains the egg nucleus and other nuclei which give rise to endosperm on fertilization.
So the correct option is 'all of these'

In ovule, functional megaspore develops into ______________.

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Pollen mother cell-PMC

  2. Megaspore mother cell-MMC

  3. Embryosac

  4. Both 2 and 3

Show answer
Correct Option: A

From which part of the ovary do seeds and fruit develop?

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Ovaries; Ovules

  2. Ovules; Ovaries

  3. Ovules; Stamens

  4. Stamens; Ovaries

Show answer
Correct Option: B
Explanation:

The ovule  develops into seed and ovary develops into fruit and seeds are enclosed within the fruit. Both are result of fertilisation in angiosperm plant. 

In ovule, endothelium is

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Nucellus

  2. Nucellus surrounding embryo sac

  3. Tissue near chalaza

  4. Inner part of integument

Show answer
Correct Option: D
Explanation:
In some plants having unitegmic and tenuinucellate ovules, the nucellus degenerates at an early stage. In such ovules, the innermost layer of the integument becomes specialized to perform the nutritive function of the growing embryo sac. This specialized tissue is called the Endothelium. The endothelium is generally single layered and the cells are radially elongated and have dense cytoplasm. Hence, in the ovule Endothelium is the inner part of the integument.
So, the correct answer is D.

In 82% of angiosperm families, ovule is

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. Anatropous

  2. Orthotropous

  3. Amphitropous

  4. Circinotropous

Show answer
Correct Option: A
Explanation:
In gymnosperms, the ovules lie uncovered on the scales of the cone. In angiosperms, one or more ovules are enclosed by the ovary (the portion of the carpel or female reproductive organ). Each ovule is attached by its base to the stalk (funiculus) that bears it. 
Based on the form and position of the ovule they are classified as orthotropous are simplest and primitive type ovules stand out straight into the cavity of the ovary; campylotropous ovules are at right angles to the funiculus; anatropous are most common type  ovules are directed back toward the funiculus or completely inverted ovule turned back 180 degree on its stalk. Intermediate forms also occur
So, the correct answer is 'Anatropous'

Choose the correct answers from the alternatives given.
The ovule is comparable to

botany asexual and sexual reproduction in plants structure of male and female reproductive structures structure of ovule gynoecium

  1. megasporangium

  2. microsporangium

  3. megasporophyll

  4. microsporophyll

Show answer
Correct Option: A
Explanation:

In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: The integument(s), forming its outer layer(s), the nucellus (or remnant of the megasporangium), and the female gametophyte (formed from a haploid megaspore) in its centre.

So, the correct option is, 'megasporangium'.