Wk 2- The Cell Cycle & Mitosis

Mitosis= parent cell divides and creates 2 identical daughter cells Meiosis = division of sex cells to produce gametes , division of 1-4 genetically different cells Cells divide to ~ Grow new t? Replace d? / dead cells

The cell phase can be divided into 2 phases. • The ? ( G?, ? Phase ,G?) • The M? Phase (P/M/A/T)

Interphase: G1 , S phase , G2 G1: = ?phase 1 ? Phase Replication of o? and cellular components S phase= s? DNA Complete c? of DNA are made before progressing G2= ? Phase 2 ? Growth phase E? and centrosome replication is completed Preparation for d? to move onto 2nd phase

Cell cycle check points Check points ensure that the cell is ? to move onto the next stage. Avoids production of unhealthy /m? cells

Mitotic phase = the division of chromosomes into 2 separate N? The 4 stages are ?

Prophase = the 4 c’s and K Chroma? Fibres condense = chromo? Identical pairs of chromosomes = chroma? The chroma? is held at the centre by Centro? The centro? is surrounded by kin?

Metaphase: Chromosomes migrate to the ? of the cell. They align across the ? Plate

Anaphase: Mitotic s? fibres attach to k? and pull chromatids apart. The chromatids are then pulled to o? poles of the ?

Telophase: Chromosomes uncoil. N? envelope forms around chromosomes. An evident c? furrow begins. This is the last stage before cytokinesis

Cytokinesis = the complete ? division of all cytoplasm / o? Creation of 2 ? cells Each is identical / equal in DNA and ? 1 continues to r? in the cycle the other leaves the cycle as a new cell .

Karyotypes= the ? and appearance of ch? in the n? of a ? Cell. The sets of ? may be lined up in their pairs.

DNA replication = ? Phase complete and exact copy is made Enzymes assist the replication ~ Helicase RNA primers Primase DNA polymerase Free nucleotides

DNA replication • H? Bonds break , helix opens and Enzyme ? unravels the helix • Enzyme p? builds — primers on existing DNA strands to give DNA poly? a place to begin new strands of ? • DNA poly? adds free n? to growing new DNA strand • 2 identical double helices remain , 1 new strand and 1 o?