Week 8: The Cell Cycle

University:
The Pennsylvania State University
Course:
BIOL 230W | Cellular Biology
Academic year:

2023
Views:

20

Pages:

1
Author:

Sarah Landeck

BIOL 230W - Week 8 The Cell Cycle — Stages of cycle = G0 (cell is not dividing), interphase (G1 - growth, S - one round of replication, G2 - growth, prep for M), and M (mitosis) — The centromere attaches 2 sister chromatids (region of DNA) —> Chromatids have regions of euchromatin (expressed at high levels) and heterochromatin (expressed at low levels) —> Cohesin is made of proteins and sticks chromatids together — Replicated chromosomes separate during anaphase of mitosis The Cell Cycle pt 2 — Tubulin dimers have an alpha and beta subunit and polymerize to form hollow tube called a microtubule (alpha gets added to previous beta, directionality) —> can depolymerize bc they are associated via hydrogen bonds on + end — Centrosome initiates polymerization of tubulin to make microtubules —> centrosomes duplicate during S phase of cell division — During prophase, centrosomes migrate to opposite poles — During pro metaphase, the nuclear membrane dissolves, allowing tubulin to enter nucleus and attach to chromosomes using kinetochore (protein) — During metaphase, chromosomes are balanced and line up at midline — *cell diagram — During anaphase, sister chromatids separate and migrate towards poles — Nuclear membrane reforms during telophase — Kinesin moves towards the + end of tubulin and pulls chromosome to poles