Post on 15-Feb-2016
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Cancer cells grow and divide when they should not
• Mitosis – an asexual cell division, that occurs in somatic cells– “Soma” = body
• Cell cycle – the “lifecycle” of the cell
The Cell cycle: Interphase
• Interphase has three phases:– G1: cell grows, organelles
duplicate– S: DNA is replicated– G2: cell makes proteins
needed to complete cell division
DNA replication
• Produces exact copies of the cells chromosomes
• Nucleotides are added by an enzyme called DNA Polymerase
• semiconservative replication - each newly replicated DNA molecule contains a daughter and a parental DNA strand
Following replication, the DNA sequence ACCGTA would be paired with a daughter DNA strand with the sequence:
A. ACCGTAB. TGGCATC. ATGCCAD. UGGCAT
A. B. C. D.
25% 25%25%25%
• Chromosomes are uncondensed before cell division
• Duplicated chromosomes are called sister chromatids
• They are held together at the centromere
DNA replication duplicates chromosomes
• Mitosis produces genetically-identical daughter nuclei
• Four stages:– Prophase– Metaphase– Anaphase– Telophase
• Mitosis is followed by cytokinesis, which splits the two nuclei into two daughter cells
The Cell cycle: Mitosis
Mitosis : Prophase and Metaphase
Mitosis : Anaphase and Telophase