Which structures are haploid? Select all that apply.
A) Zygote
B) Gametophyte
C) Sporophyte
D) Spores
E) Egg
The Correct Answer and Explanation is :
The correct answers are:
B) Gametophyte
D) Spores
E) Egg
Explanation:
In biology, haploid refers to a cell or organism that contains only one set of chromosomes, as opposed to diploid, which contains two sets. Let’s break down the choices:
- A) Zygote: A zygote is a diploid structure. It is formed when two haploid gametes (sperm and egg) fuse during fertilization. The fusion restores the diploid number of chromosomes, so the zygote is not haploid.
- B) Gametophyte: In the alternation of generations seen in plants, fungi, and some algae, the gametophyte is the haploid phase. The gametophyte produces gametes (eggs and sperm) through mitosis, and these gametes are also haploid. Therefore, the gametophyte is haploid.
- C) Sporophyte: The sporophyte is the diploid phase in the alternation of generations. It is formed after the fertilization of gametes and produces haploid spores through meiosis. However, the sporophyte itself is diploid, not haploid.
- D) Spores: Spores are the result of meiosis and are haploid. They can develop into gametophytes (the haploid phase) without fertilization. Therefore, spores are haploid structures.
- E) Egg: Eggs are gametes, and like sperm, they are haploid. Eggs contain only one set of chromosomes, which combine with the sperm’s haploid chromosomes during fertilization to form a diploid zygote.
Summary:
Haploid structures are those that contain one set of chromosomes. In the context of plants, fungi, and other organisms with alternation of generations, the gametophyte, spores, and eggs are haploid, while the zygote and sporophyte are diploid.