Bio 1A03 Test 3 Questions And Answers 2023

Binary Fission steps - -Initiated when proteins attach DNA to plasma membrane -Begins along ORI region -Newly synthesized DNA also anchored to membrane -Cell elongates until ~2 times its original size and two has two chromosomes on opposite ends of the cell -Cell splits in two Quiescent stem cells, function - Permanently arrested in G0 phase. In adults: can replace non-reproducing specialized cells) ex adult skeletal muscle/myofiber) Steps of quiescent stem cell to myofiber - -Activated (reenter cell cycle) -Proliferative (look over this one) -Commitment to differentiation -Fusion into myotube (precursor of myofiber) -Myofiber steps of cell cycle - G1 phase S phase G2 phase M phase ~G0 phase~ perhaps G1 phase - growth phase, prepares cell for dna synthesis s phase - cell undergoes dna replication g2 phase - growth phase, cell prepares for division M phase - mitosis and cytokinesis cells in permanent g0 phase - eye lens, nerve, mature muscle cells binary fission is common to - bacteria, archaea, mitochondria, chloroplasts Satellite Stem Cells - quiescent stem cells that specifically are activated to replace injured muscle fibers Walter Flemming - Discovered stages of mitosis from salamanders During interphase, the genetic material of a typical eukaryotic cell is - chromatin fiber genetic material during s phase - sister chromatids are synthesized (including centromere) but chromosomes don't actually compact until M phase (46 X-shaped not linear chromosomes / 92 chromatids) chromatids - chromosome in duplicated state # chromosomes and chromatids in human before & after mitosis, meiosis I, and meiosis II - Mitosis Before: 46, 92 After: 46, 46 Meiosis I Before: 46, 92, After: 23, 46 Meiosis II Before: 23, 46 After: 23, 23 genetic material during interphase - chromatin fiber, can't identify specific chromosomes prophase (mitosis) - identical sister chromatids apparent centrosomes (microtubules) form mitotic spindle and positioned at opposite ends of the cell centromere vs centrosome - centromere: holds together two sister chromatids into 1 chromosome centrosome: hold together mitotic spindles prometaphase - fragmentation of nuclear envelope allows mitotic spindle to attach to kinetochores on centromeres kinetochores - The structures on sister chromatids where microtubules attach 1) some microtubules attach directly and pull 2) some k.c are polar and repel the sides of the cell from each other metaphase (mitosis) - chromosomes line up along middle of metaphase plate, facilitated by kinetochore microtubules attaching to the kinetochores of each sister chromatid anaphase (mitosis) - kinetochore microtubules shorten and pull apart chromosomes polar microtubules repel each other and help elongate the cell equal segregation of chromosomes (or stop)