Download cell cycle

Cell Division
• Prokaryotic
 binary fission
 sporulation
• Eukaryotic
 mitosis
 meiosis
Prokaryotic Cell Division - Binary Fission
Eukaryotic DNA is Packaged into Chromosomes
Chromosomes, Chromatids, and Chromatin
spectral karyotype
Karyotypes
Numbers of Chromosomes in Some Plant and Animal Species
Yeast
Saccharomyces cerevisiae
16
Mitosis
The Mitotic Spindle Consists of Microtubules
Mitosis
Mitosis
Cytokinesis Differs in Animal and Plant Cells
The Eukaryotic Cell Cycle
Checkpoints in Cell Cycle Progression
• G1 to S and G2 to M transitions are
regulated by proteins called cyclindependent kinases (Cdks) and cyclins
Cyclin proteins and Cdk activity
• Cyclin proteins are made and destroyed in a cyclic
pattern during the cell cycle
• Cdks are activated by binding to one of several different
cyclin proteins
Cyclins and activation of Cdks
Cyclin-Dependent Kinases and Cyclins Regulate Transitions in the Cell Cycle
MPF
• Cdk-cyclin
complexes each
phosphorylate
different target
proteins to
regulate
progression of
the cell cycle
p53
Disruption of Cell Cycle Control
• Cyclin-Cdk complexes act as checkpoints.
• When functioning properly, they allow or prevent passage
to the next stage of the cell cycle
• In cancer cells, these checkpoints are often disrupted
 Rb/p105 (retinoblastoma)
 Loss of Rb permits unregulated cell division
 p53
 Loss of p53 prevents synthesis of p21 which
allows production of cyclin D
Asexual Reproduction
Meiosis and Alternation of Generations in Sexual Reproduction
Meiosis I
Crossing Over Forms Genetically Diverse Chromosomes
Meiotic
Recombination
Chiasmata: Evidence of Exchange between Chromatids
Meiosis I
Meiosis I
Meiosis II
Meiosis II
Meiosis II
Mitosis and Meiosis: A Comparison
Mitosis and Meiosis: A Comparison
Nondisjunction Leads to Aneuploidy
Apoptosis: Programmed Cell Death
Two Different Ways for Cells to Die