Human Genetics Cell Reproduction Flashcards
Cells divide and reproduce in 2 ways:
Mitosis and Meiosis
Define Mitosis:
Cell division, one cell divides once to form 2 identical diploid daughter cells
Define Meosis:
Cell division to produce germ cells(sperm & ova)
1 cell divides TWICE to form 4 nonidenticial daughter cells which reduces the chromosomes # by half (haploid cells)
The prupose of Mitosis:
Growth and replacement of worn out cells
What are the 5 phases of Mitosis
Interphase Prophase Metaphase Anaphase Telophase
Describe Interphase:
The normal life cycle id the cell
The nucleus & nucleolus are well defined
DNA is present but NOT visible in nucleus
Outside the nucleus, are a pair of centrioles
DNA is duplicated, making 2 copies of DNA= 2 chromatids
What happens when the cell becomes close to transitioning into the 2nd phase Prophase?
Chromatin replicates to form 2 identical copies of DNA
Describe Prophase:
Chromatin coils tightly & becomes visible under a microscope
Two copies of DNA, sister chromatids are present
Nuclear membrane dissolves releasing chromosomes into cytosal
2 pairs of centrioles move to opposite sides of cell
Microtubules extend outward from each pair of centrioles forming spindle fibers across the cell
Describe Metaphase:
Chromosomes line up along center of the cell
Describe Anaphase:
Centromere splits and sister chromatids pull apart to opposite sides of the cell
Describe Telophase:
Nuclear membrane reforms around chromatids
Chromosomes uncoil and return ti chromatin state
Cytoplasm and cell membrane pinch along the equater of the cell
End result: 2 indentical daughter cells
