ZOO 3050 Lecture Notes - Lecture 4: Seminiferous Tubule, Gonadal Ridge, Gametogenesis
Document Summary
Egg morphology: egg functions, protection, nutrition for embryo. In humans, small egg because it requires minimal nutrient (access to mother"s nutrients when it implants in uterine wall) Spermatogenesis: pgcs inhabit testis, seminiferous tubule: located in testicles and specific location for spermatogenesis, sertoli cells: accessory cells associated with. Transition from spermatogonia to spermatid: spermatids-differentiate into mature sperm cells, condensation of nucleus, spermatids produce protamines positive charged proteins neutralizing the negative charge of the dna helix phosphate backbone, allows dna to become tightly packed no gene expression possible. Make animal: cellular machinery for growth and early development, ribosomes, trna, mitochondria. Informational molecules: mostly mrna to direct early development, these are instructions from mother. Meiosis in the mouse oocyte: tubulin(microtubules)=green, dna=blue, steps, meiotic prophase, diploid nucleus, start of metaphase, nuclear envelope breaks down, meiotic anaphase i, spindle migration to cell periphery, meiotic metaphase ii, release of second polar body. Differences in oogenesis between species: mammals produce all primary oocytes before birth.