Questions: Angiosperm Reproduction and Double Fertilization
4 questions to test your understanding
Score: 0 / 4
Question 1 Multiple Choice
What is the chromosome number of the endosperm in a typical flowering plant?
AHaploid (n)
BDiploid (2n)
CTriploid (3n)
DTetraploid (4n)
One sperm (n) fuses with the central cell, which holds two haploid polar nuclei (n + n). The result is a triploid (3n) cell that divides to form the endosperm.
Question 2 True / False
A pea pod is a fruit, and the peas inside it are seeds.
TTrue
FFalse
Answer: True
Botanically, a fruit is a mature ovary. The pod is the ovary wall, and each pea developed from a fertilized ovule. Many foods called vegetables, such as pea pods, tomatoes and cucumbers, are fruits in this sense.
Question 3 Short Answer
Why is double fertilization thought to be an efficient arrangement for the plant?
Think about your answer, then reveal below.
Model answer: Because the endosperm forms only when the second sperm fuses with the central cell, the plant invests food in a seed only when fertilization actually occurs. Ovules that are not fertilized do not develop endosperm, so the plant does not waste resources on them.
Linking food storage to fertilization keeps resources from being spent on unfertilized ovules. The endosperm then feeds the embryo, either as the seed develops or during germination.
Question 4 Multiple Choice
In the anther, which process produces the haploid microspores that develop into pollen grains?
AMitosis of diploid cells
BMeiosis of diploid microsporocytes
CFertilization
DFusion of polar nuclei
Diploid microsporocytes in the anther undergo meiosis to produce haploid microspores. Each microspore then divides by mitosis to form a pollen grain, the male gametophyte, which contains a tube cell and a generative cell that later yields two sperm.