Exam 3 - Mitosis & Cell Division Flashcards
- Prophase ( supercoiling )
- genetic material condenses into compact chromosomes
- nuclear envelope breaks down
Where do spindle fibers form
Form from centrioles during prophase
Metaphase (alignment)
Chromosomes line up along central line
Metaphase - chromatids ?
Each sister chromatid is attached to a spindle fiber , originating from opposite poles
Anaphase (poles)
- Centromeres split in two
- spindle fibers begin to elongate cell
Anaphase - chromatids
Sister chromatids separate and migrate to opposite sides of the cell
Telophase (division)
- Chromosomes arrive at opposite poles and begin to decondense
- mitotic spindle breaks down
Telophase
- nuclear envelope material surrounds each set of chromosomes
-Each (2) nucleus is genetically identical
(Same amount + type of chromosome)
Outcome of mitosis
Duplicate set of chromosomes with 2 separate nuclei
Cytokinesis
Actual division of cells into two daughter cells
(2nd pt of mitotic phase)
Cytokinesis in animal cells
Cleavage furrow seperates 2 daughter cells
Cytokinesis in plant cells
Cell plate seperates cursor cells
Telomeres
Ends of chromosomes
-repeated sequences of TTAGG
-thousands of nucleotide base pairs
“Molecular clock”
Telomeres
What happens when a telemore is replicated
It loses a few bases at the end of its chromosomes
How to senescent cells occur
Telomeres become too short , cells become senescent
Negatives of senescent cells
Disrupt homeostasis
What repairs telomeres
Telomerase (enzyme).
Oncogenes
Genes that cause a cell to become cancerous
Cancer cells
-irregular shape
-Immortal
- lose ability to specialize
Why do Cancer cells grow uncontrollably
Lost use of specialized proteins that send stop and go signals in cell cycle
Cancer cells
