Chapter 20, Problem 15A

Summary Introduction

To explain:

The differences between the vocabulary terms in ascospore and ascus.

Introduction:

Fungi are classified or divided by their structure and patterns of reproduction. Some fungi only can reproduce asexually through mitosis. Asexual reproduction in fungi also includes budding, fragmentation, and spore production. Many fungi can show sexual and asexual reproduction. Sexually reproducing fungi produces spores by the process of meiosis.

Explanation of Solution

Ascomycete sexual reproduction is a complicated process. The sexual reproduction in ascomycetes takes place when the hyphae from opposite mating types fuses and one nucleus from each type pairs off in separate cells. The development of hyphae into a special reproductive structure is known as ascocarp. Within an ascocarp, the haploid nuclei fuse to form a zygote. The zygote divides by meiosis, producing 4 haploid nuclei. These nuclei then divide by mitosis, forming a total of 8 haploid nuclei. An ascus is a saclike structure that carries the nuclei and developed them into spores. The spores produced by an ascus are known as ascospores.

Conclusion

Thus, the ascus is a saclike structure and ascospores are the spores produced by an ascus.