Biology Multiple Choice Questions on “Flowering Plants Reproduction – Structure of Embryo Sac”.
1. Which half is the embryo sac embedded?
a) Funicle
b) Ovule
c) Micropylar
d) Chalaza
Answer: c
Clarification: The embryo sac is embedded in the micropylar end of the nucellus. Nucellus consists of the body of the embryo that is made up of parenchymatous cells. Its equivalent to microsporangium.
2. Label the part marked with a blue arrow.
a) Chalaza
b) Micropyle
c) Egg
d) Nucellus
Answer: d
Clarification: It’s the nucellus. Nucellus is the place where the embryo sac rests. It is made up of cushiony cells called parenchymatous cells. Nucellus helps in the nourishment of the embryo sac.
3. Label the part marked in blue arrow.
a) Polar nuclei
b) Synergids
c) Antipodal cells
d) Placenta
Answer: a
Clarification: Polar nuclei are 2 haploid cells. Either one of them will fuse with a male haploid cell to form an endosperm. They undergo the process of double fertilization–2 female gametophytes fuse with 2 male gametophytes.
4. Label the part marked by the blue arrow.
a) Synergids
b) Antipodal cells
c) Polar nuclei
d) Funicle
Answer: b
Clarification: They are the 3 mature cells in the embryo sac present opposite to the micropylar end. The function of the antipodal cells is to provide nutrition and nourishment to the embryo sac.
5. ________ distinguished between bisporic and tetrasporic.
a) Mendel
b) Nirenburg
c) Maheshwari
d) Kvitova
Answer: c
Clarification: Maheshwari distinguished between bisporic and tetrasporic. Bisporic embryo sacs develop from 2 megaspores and tetrasporic embryo sacs develop from 4 megaspores.
6. ______ apparatus is a mass of finger like projections on the synergid wall.
a) Egg
b) Chalaza
c) Micropylar
d) Filiform
Answer: d
Clarification: Filiform apparatus is a mass of finger like projections of the wall of the synergid cells into the cytoplasm. It may or may not be present. It guides the male gametophytes during fertilization.
7. How do the 3 cells of the egg apparatus communicate?
a) Plasmodesmata
b) Nucellus
c) Cytokine
d) Vacuole
Answer: a
Clarification: The 3 micropylar cells are collectively known as the egg apparatus. They share a common wall. Its through the plasmodesmata that the 3 cells communicate.
8. What are 3 chalazal cells called?
a) Synergids
b) Antipodal cells
c) Polar nuclei
d) Chalaza
Answer: b
Clarification: The 3 chalazal cells are called antipodal cells. These are vegetative cells that provide nourishment to the embryo sac. After fertilization these cells degenerate. Internally they are connected to the central cell by plasmodesmata.
9. All cells in the megaspore are functional.
a) False
b) True
Answer: a
Clarification: All cells are not functional. Only the egg and the central cell is involved in double fertilization. One synergid receives the pollen tube. The antipodal cells provide nourishment and then degenerate.
10. Which is the largest cell of the embryo sac?
a) Chlazal cells
b) Micropylar cells
c) Synergids
d) Central cell
Answer: d
Clarification: The central cell is the largest cell. In the middle it contains 2 polar nuclei which have large nucleoli. It is a highly vacuolated cytoplasm which is rich in reserve food and golgi bodies.