Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What is the key process described as 'double fertilization' in flowering plants?

1. Fertilization of two separate plants

2. Formation of two embryos in one seed

3. Fertilization resulting in the formation of both an embryo and a triploid endosperm

4. Fertilization of ovules by two different types of pollen

The correct answer is: Fertilization resulting in the formation of both an embryo and a triploid endosperm

Double fertilization is a unique reproductive process observed in flowering plants (angiosperms) that involves two distinct fertilization events occurring within the ovule. The correct answer highlights that double fertilization results in the formation of both an embryo and a triploid endosperm. During this process, one sperm cell fertilizes the egg cell, resulting in the formation of the diploid zygote, which later develops into the embryo. Simultaneously, another sperm cell fuses with two polar nuclei in the center of the ovule, giving rise to the triploid endosperm. This endosperm serves as a nutrient-rich tissue that supports the developing embryo during its initial growth stages after germination. This phenomenon is significant as it ensures that the embryo has a food supply when it begins to grow, which enhances its chances of survival. The triploid endosperm is a unique aspect of angiosperm reproduction and distinguishes it from other plant reproductive strategies.