Q.7 - Biology

Question

During sexual reproduction, a homothallic mycelium contains 

a. all septated hyphae 

b. all haploid nuclei 

c. both mating types 

d. none of the above 

Step-by-Step Solution

Answer

The correct answer is (c) both mating types. 

During sexual reproduction, a homothallic mycelium contains  both mating types.  

Step1. Introduction

Homothallic refers to the possession, within a single organism, of the resources to reproduce sexually; i.e., having male and female reproductive structures on the same thallus. The opposite sexual functions are performed by different cells of a single mycelium. 

Step2. Explanation of the correct answer

During sexual reproduction, two mating types are produced. When both mating types are present in the same mycelium, it is called homothallic. 

Step3. Explanation for Incorrect Options

a. all septated hyphae 

Septate hyphae have dividers between the cells, called septa (singular septum). The septa have openings called pores between the cells, to allow the flow of the cytoplasm and nutrients throughout the mycelium. 

b. all haploid nuclei 

A nucleus with one set of chromosomes is called a haploid nucleus, the haploid nuclei are contained in cells of some sort and naturally a cell with a haploid nucleus is called a haploid cell.

The first step towards fusion of the nuclei is the fusion of two haploid cells and this step is called plasmogamy. 

d. none of the above 

Since option (c) both mating types is correct, hence this option is incorrect.