SCIE1106 Lecture Notes - Lecture 25: Sister Chromatids, Cell Cycle, Nissan L Engine
L26 Cell Cycle + Apoptosis
• Mitosis’ keysteps
• Chromosome’s structure + how they behave
during eukaryotic cell cycle
• Meiosis keysteps
• Mitosis/Meiosis differences
• Understand the need + process of apoptosis
• Cytokinesis, karyokinesis,
chiasma,caspase,zymogen
Homeostasis
• Tendency towards a relatively stable equilibrium
between interdependent elements, especially as
maintained by physiological processes
Homeostasis of human cells
• Differentiated (adult cells) cells, are in a steady
state system, aka homeostasis
• Rate of cell death equals to = cell division
Cell proliferation
• Controlled by cell cycle
• Ie an ordered series of events, leading to
replication of cells, aka a dynamic system
o Energetic system
Cell death
• Necrosis – cells die because of trauma, toxins,
infections
• Apoptosis – controlled cell death
Chromosome structures
• DNA double helix, with a linear sequence of genes
• During S phase of interphase, DNA is replicated
• Resulting 2 identical copies are connected to each
other at the centromere
• Each pair – is called sister chromatids
Mitosis
Meiosis
2 cells with same # of
chromosomes as the parent
cell are produced
aka somatic cell division
Cells with ½ # of
chromosomes as the
parent cells are produced
Aka gamete production
Maintenance division –
genetic material is
maintained
Reductional division –
ensures genetic material is
not doubled in new
generations of sexually
reproducing organisms
Diploid
Haploid
Cell cycle – Eukaryotes (animals, fungi, plants, protists)
• 2 phases (interphase + mitosis)
• Interphase – period between cell divisions
o Cell grows, develops & prepares for
division
o Could be ¾ phases (G1, S, G2, G0)
• Mitosis – process of karyokinesis & cytokinesis
o Karyokinesis – nuclear division
o Cytokinesis- cytoplasmic division
o 5 phases PPMAT
o Mitosis is followed by cytokinesis = aka
cell division
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
2 cells with same # of chromosomes as the parent cell are produced aka somatic cell division. Cells with # of chromosomes as the parent cells are produced. Reductional division ensures genetic material is not doubled in new generations of sexually reproducing organisms. L26 cell cycle + apoptosis during eukaryotic cell cycle: mitosis" keysteps, chromosome"s structure + how they behave, meiosis keysteps, mitosis/meiosis differences, understand the need + process of apoptosis, cytokinesis, karyokinesis, chiasma,caspase,zymogen. Homeostasis: tendency towards a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes. Homeostasis of human cells: differentiated (adult cells) cells, are in a steady state system, aka homeostasis, rate of cell death equals to = cell division. Ie an ordered series of events, leading to replication of cells, aka a dynamic system. Cell death: energetic system, necrosis cells die because of trauma, toxins, apoptosis controlled cell death infections. Cell cycle eukaryotes (animals, fungi, plants, protists)
