zoology terms pt 2

zoology terms pt 2 - Final Exam Second Section Terms - - -...

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Final Exam – Second Section Terms - Organogenesis – 1 mature ovum for each primary oocyte; growth and differentiation before meiosis o In spermatogenesis – 1 primary spermatocyte = 4 sperm; growth before, differentiation after meiosis - Previtelogenic stage – formation of information, mRNA, proteins, cell machinery; diplotene stage arrest - Diplotene stage arrest – can be very long; all oocytes in this stage just before the oocytes ovulate - Vitellogenic stage – nutrient storage - Single copy DNA – lampbrush chromosomes, code for mmRNA, have extended half-life - mmRNA – maskin, minus cap protein, etc. - Repetitive DNA – rRNA production in the nucleolus called gene amplification; inside GV are supernumerary nucleoli, which are not attached to chromatin - Solitary gonads – oocytes receive nutrients from maternal fluids with no helper cells - Alimentary gonads – oocyte relies on follicle/nurse cells - Follicular cells – follicle cells, transport by gap junctions or pinocytosis - Nutrimentary – relies on nurse cells, follicle cells are also present; no lampbrush chromosomes or supernumerary nucleoli; polytene chromosomes (meroistic ovary – characteristic of insects) - Merioistic ovaries – typical of insects and annelids; Ovary divides until 16-cell stage. Of these cells, 2 will have four intercytoplasmic bridges. Only one of these two will become the ovum – the one that retains the fusom. The fusom is a spectrin-rich region - Cytochalasin b – inhibits actin microfilaments - Colchicines – inhibits microtubule polymerization (colcemid in humans) - Amphibian vitellogenesis – The hypothalamus sends a GnRH signal to the follicle cell. The follicle cell makes estrogen, which goes to the liver. The liver makes vitellogenin, which goes back to the cell and taken in by the follicle. - Insect vitellogenesis – brain releases a juvenile hormone from the brain and corpis allatum. This goes to the follicle cell. The follicle cell gives off ecdysone, which goes to the fat body. The fat body gives of vitellogenin and goes back to the cell. - Oligo-, iso-, homolecithal – equal even yolk distribution, small eggs (humans) - Mesolecithal – moderately dense yolk stores, uneven distribution (amphibians) - Telolecithal, Megalecithal – large yolk stores, displaced into a small disc area (chicken, reptiles, dinosaurs) - Centrolecithal – yolky eggs, nucleus centrally located (insects, arthropods) - Amphibian oocyte production – continually producing oocytes and maturing them on seasonal bases - Human oocyte production – reach a peak of about 6.5 million oocytes, then they immediately degenerate at birth. - Cortical granule – exocytotic, contain proteases, produced from the golgi - Reflex ovulation – cervical stimulation (rabbits) - Periodic ovulation – regular cyclic release of oocyte (mammals) - Menses – slothing off of uterine lining
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- Menstrual cycle – no distinct period of female receptivity to male o Ovarian cycle – mature and release ovum
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zoology terms pt 2 - Final Exam Second Section Terms - - -...

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