Respuesta :
Answer:
Step 1: Plasmogamy occurs before karyogamy
Step 2: plasmogamy produces heterokaryotic cells
Step 3: karyogamy begins after fertilization.
Step 4: karyogamy creates diploid spores.
Step 5: Zygotes produces haploid
Step 6: Spores forms from haploid
Explanation:
Karyogamy is the last step in the cycle of fusing together two haploid eukaryotic cells and refers specifically to the fusion of the two nuclei. Ahead of karyogamy, each haploid cell has one finished copy of the organism's genome. In order for karyogamy to occur, the cell membrane and cytoplasm of each cell must fuse with the other in a process known as plasmogamy. Once within the joined cell membrane, the nuclei are referred to as pronuclei. Once the cell membranes, cytoplasm, and pronuclei fuse together, the resulting single cell is diploid, containing two copies of the genome. This diploid cell, called a zygote or zygospore can then enter meiosis (a process of chromosome duplication, recombination, and division, to produce four new haploid cells), or continue to divide by mitosis. Mammalian fertilization uses a comparable process to combine haploid sperm and egg cells (gametes) to develop a diploid fertilized egg.
Answer: The correct answer is option A.
plasmogamy occurs before karyogamy
In fungal sexual reproduction,plasmogamy occurs before karyogamy.
Explanation: The fungal sexual reproduction allows the fungus to adapt to new environment, In fungal sexual reproduction,three(3) sequential stages are involved; plasmogamy,karyogamy and meosis.
When a diploid chromosomes of a fungal cell pulls apart to form daughter cells,each will form a single set of chromosome which is in haploid state,there will be fusion of the content of the two cells (protoplasts),a process known as plasmogamy,this fusion brings together two compatible haploid nuclei and at this point,two nuclear types are present in the same cell, but the nuclei have not yet fused.
Thereafter,these haploid nuclei get fused together and a diploid nucleus is formed (a nucleus containing two sets of chromosomes,one from each parent),this process is known as karyogamy.the cell formed by karyogamy is known as the zygote.
Once karyogamy has taken place,meiosis cell division that reduces the chromosome number to one set per cell generally follows and restores the haploid phase. The haploid nuclei that result from meiosis are generally incorporated in spores called meiospores.
