Question

Which of the following statements about double fertilization are true? Select all that apply. a. One sperm fuses with an egg while the other sperm fuses with the polar nuclei. b. It results in the formation of a diploid embryo and triploid endosperm. c. Both sperms involved in double fertilization form within the same pollen tube. d. The diploid nucleus resulting from the second fertilization undergoes meiosis to form the endosperm. e. Two zygotes are formed, but only one survives.

Answer 1

Answer: Option A,B,C and D.

A) one sperm fuses with an egg and the other fuses with polar nuclei.

B) It results in the formation of diploid embryo and triploid endosperm.

C)Both sperm involved in double fertilization form within the same pollen tube.

D).The diploid nucleus resulting from the second fertilization undergoes meiosis to form endosperm.

Explanation:

Double fertilization is a mechanism that occur in flowering plants(angiosperms) in which two female gametes(embryo sac) is fertilized by two sperms. It starts when pollen grain join to stigma, the pollen grain then grow in the presence of moisture to form pollen tube. The pollen tube released two sperms,One sperm fuses with the egg cell and the other sperm fuses to the two polar nuclei, it produces diploid embryo and triploid endosperm. The diploid nucleus from the second fertilization of polar nuclei, undergoes meiosis to produce endosperm. Double fertilization is important in that it restore stimulus to plants, Ovary develop into fruits and ovule into seeds and it also lead to production of diploid zygotes which develop into new plant.

Answer 2

Answer: Only options A, B, C and D are true statements

A) One sperm fuses with an egg while the other sperm fuses with the polar nuclei.

B) It results in the formation of a diploid embryo and triploid endosperm.

C) Both sperms involved in double fertilization form within the same pollen tube.

- The diploid nucleus resulting from the second fertilization undergoes meiosis to form the endosperm.

Explanation:

Double fertilization is a process that occurs in only flowering plants. It involves the following:

- A pollen grain produces TWO male gametes

- one male gamete fertilize the egg to form a zygote that is DIPLOID (with two basic sets of chromosomes)

- the second male gamete fuses with another cell named POLAR NUCLEI, to form endosperm (the food storing tissue) in the seed. The endosperm formed is TRIPLOID ( it has three sets of chromosomes), having undergone reductive division - meiosis

Thus, the options A, B, C and D are true statements