Task

Cat somatic cells contain 38 chromosomes (2n = 38). Spermatogenesis is studied in a tomcat’s testis; 50 primary spermatocytes were selected. 1) Describe the stages of spermatogenesis (multiplication, growth, maturation, formation) and the type of division in each. 2) Show with formulas how the chromosome set (n) and DNA content (c) change in each phase of mitosis and meiosis. 3) Find the number of chromosomes, chromatids (DNA molecules) and bivalents in a primary spermatocyte in prophase I. 4) Find the number of chromosomes and chromatids in a secondary spermatocyte in metaphase II. 5) Find the number of chromosomes and DNA molecules in anaphase of mitosis in a spermatogonium. 6) Calculate the number of sperm formed from 50 primary spermatocytes and the total number of chromosomes in them. For each part, write out the law or method used (cross scheme, formulas, reasoning) and all calculations step by step.