Tag: male & female gametophytes: structure and development

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Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Select the correct and incorrect statements.
(a) Tapetum nourishes developing pollen grains.
(b) Hilum represents junction between ovule and funicle.
(c) In aquatic plants, Water Hyacinth and Water Lily, pollination is by water.
(d) Primary endosperm nucleus is triploid.

  1. a, b correct, c, d incorrect

  2. a, b, d correct, c incorrect

  3. b, c, d correct, a incorrect

  4. a, d correct, b, c incorrect

  5. b, d correct, a, c, incorrect
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(a) Tapetum provides nutrition to developing pollen. (b) Hilum is the junction between ovule and funicle. (d) Primary endosperm nucleus is triploid (3n) due to double fertilization. (c) is incorrect because Water Hyacinth and Water Lily are pollinated by insects or wind, not water.

Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Which one of the following statements is not true?

  1. Stored pollen in liquid nitrogen can be used in the crop breeding programme.

  2. Tapetum helps in dehiscence of anthers.

  3. Exine of pollen grains is made of sporopollenin.

  4. Pollen grains of many species cause severe allergies.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Tapetum is the innermost layer and completely surrounds the sporogenous tissue. The cells of Tapetum have dense cytoplasm and generally possess more than one nuclei. Tapetum nourishes the developing pollen grains.

The layer of the anther wall that helps in anther dehiscence is endothecium. The cells of endothecium develop fibrous thickenings at maturity which radiate from the inner tangential walls. These thickenings are made up of alpha cellulose and traces of lignin. These thickenings are hygroscopic and thus, help in anther dehiscence.
Hence, statement B is not true. So, the correct answer is B.

Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Male gametophyte in angiosperms produces

  1. Two sperms and a vegetative cell

  2. Single sperm and a vegetative cell

  3. Single sperm and two vegetative cells

  4. Three sperms
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In angiosperms the pollen grain is the male gametophyte. It consists of 2 generative nuclei/cell and 1 vegetative nucleus/cell
So, the correct answer is 'Two sperms and a vegetative cell'
Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Germ pores in the pollen grains are regions.

  1. That can withstand high temperature, strong acids and alkalies

  2. Through which sperms are released into the female gametophyte

  3. Which are made of lignin and suberin

  4. Which lack sporopollenin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Germ pores are specific areas on the pollen grain wall where the exine is thin or absent, meaning they lack the resistant sporopollenin, allowing the pollen tube to emerge.

Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Consider the following statements with respect to pollen grains.
(a) Exine is thin, continuous layer made up of cellulose and pectin
(b) Hard outer layer called exine is made of sporopollenin
(c) Sporopollenin is present in germ pores
(d) Exine exhibits a fascinating array of patterns and designs. Of the statements.

  1. a and b alone are correct

  2. a and c alone are correct

  3. b and d alone are correct

  4. b and c alone are correct
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
•Exine is a thick layer made up of sporopollenin. The exine is discontinuous in some regions where sporopollenin is absent. These regions mark the germ pores. Hence statement (a) is incorrect.
•Hard outer layer of Exine is made up of sporopollenin which is one of the most resistant known biological material. Hence statement (b) is correct.
•Sporopollenin is absent at the site of germ pores. Hence statement (c) is incorrect.
•Exine shows different patterns or sculptures due to Tectum and Bacula layers. Hence statement (d) is correct.
Therefore, statements (b) and (d) are correct.
So, the correct answer is C.
Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Choose the correct options for statements P, Q, R in relevance to grass.
Statement P: Flowers possess attractive colour and fragrance.
Statement Q: Pollen grains are small, dry and light in weight.
Statement R: Grass is air pollinated plant.

  1. Both P and Q are true, R is correct explanation of Q

  2. P is true and Q is false, R is correct explanation of P

  3. P is false and Q is true, R is correct explanation of Q

  4. Both P and Q are false, R has no relation with P and Q
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Grass is wind-pollinated (anemophilous). Statement P is false because grass flowers are not colorful or fragrant. Statement Q is true because pollen must be light and dry for wind transport. R is true and explains why Q is necessary.

Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Discontinuous layers in the wall of pollen grain are

  1. Absent

  2. Foot layer

  3. Baculate layer

  4. Baculate layer and tectum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Pollen wall comprises of two layers: outer layer exine and inner layer intine. The exine is chemically differentiated into two layers: an outer layer called "ektexine" and an inner layer called "endexine". Ektexine is further comprised of tectum, bacula and a foot layer. Above the foot layer is present a layer of rod like elements called columella or bacula, which is covered over by a roof like layer called the tectum.
The Tectum and Bacula layers form different patterns on the pollen grains as they are discontinuous at some regions and thus various types of sculptured patterns are seen in pollen grains.
So, the correct answer is D.

Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Pollen tube is covered by

  1. Exine only

  2. Plasmalemma only

  3. Intine only

  4. Exine and intine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Pollen tube emerge out from the germ pore. Exine is very thin at the site of germ pores. The pollen grain gets hydrated at the time of germination. There occurs swelling in the outer pectic layer of intine that leads to rupture of Exine. Thus, its intine that comes out in the form of pollen tube.
Hence, pollen tube is covered by Intine.
So, the correct answer is C.

Multiple choice botany male & female gametophytes: structure and development pollen grain androecium male gametophyte

Choose the correct answers from the alternatives given.
Which of the following is mismatched?

  1. Polle grain-microgametophyte

  2. Ovule-megagametophyte

  3. Seed-immature sporophyte

  4. Pollen tube-spores
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Pollen tubes are the structure that helps in the entry of the male nuclei into the ovule and then the fertilization takes place. Pollen tube does not form spores. It is just a medium that carries the male gametes.

So, the correct option is 'Pollen tube-spores'