Question

The common housefly has a haploid number of 6 consisting of 3 long chromosomes (one metacentric, one acrocentric, and one telocentric); 3 short chromosomes (one metacentric, one acrocentric, and one telocentric). Draw and label a typical housefly primary spermatocyte in Metaphase I and spermatozoa at Telophase II.

Answer 1

Spermatogenes The common housefly has a haploid number of 6 consisting of 3 long chromosomes (one metacentric, one acrocentric, and one telocentric); 3 short chromosomes (one metacentric, one acrocentric, and one telocentric). Spermertogenesis  is the process of sperm cell development. Rounded immature sperm cells undergo successive mitotic and meiMitchell c divisions (spermatocytogenesis) and a metamorphic change (spermiogenesis) to produce spermatozoa.

Mitosis and meiosis. Mitosis is the process of cell duplication - two daughter cells are formed with exactly the same DNA and chromosomal content of the original diploid (2N) mother cell. Human cells contain 46 chromosomes - 22 pairs of homologous autosomes and one pair of sex chromosomes.

Mitosis (M) encompasses just one step in the eukaryotic cell cycle: G₁ > S > G₂ > M > C. Cells grow during the dominant G₁ phase. Replication of chromosomes occurs in the S phase. Preparation for mitosis takes place during G₂ - replication of organelles and synthesis of microtubules. Interphase includes the combined stages G₁, S, and G₂. During mitosis: chromosomes condense, the nuclear envelope disappears, and spindle fibers begin to form from microtubules (prophase); centromeres of duplicate sister chromatids align along the spindle equator (metaphase); chromatids separate and migrate toward opposite poles (anaphase); the mitotic apparatus is disassembled, autonomous nuclear envelopes are established, and the chromosomes uncoil (telophase). The final stage of the cell cycle, when cell division occurs, is called cytokinesis (C).