Mitosis Flashcards
How are cells Asexual reproductive
DNA is copied making two genetically identical cells (budding, fragmentation) through a process called mitosis
Purpose of mitosis (cells dividing)
Growth: cell division increases the cell number, which increases the size of the organism
Repair: repair or replace dead cells
Reproduction: divide sexually or asexually to copy or pass on dna
Histone
A structural protein that helps organize and package dna
Nucleosome
A section of dna wrapped around histones
Chromatins
DNA and proteins (histones) together in a less condensed form
Chromatids
A Duplicated chromosome with the exact same DNA which held together by centromere, known as chromatid sisters
What is a Centromere
A structure that holds sister chromatids together
What are Chromosomes
Fully condensed and organized chromatins
Chromosome stages
1) Chromatin: DNA and Histone that isn’t condensed before reproduction
2) Chromosomes: DNA and Histone condense during reproduction
3) chromatids: Chromosomes are duplicated forming two sisters chromatids
4) once reproduction is done and cells split it goes back to a chromatin
Chromosomes purpose
Chromosomes contain segments of dna (genes) which have a particular trait, and these genes are inheritable
Chromosomes > gene > trait > inherited
Chromosomes location
Chromosomes are located in the nucleus
How many chromosomes do Diploid Cells have
Human cells (diploids) contain 23 pairs of chromosomes. One from the mother and one from the father, making a total of 46 strands of chromosomes
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What are cells Haploids
Sex cells (egg and sperm) contain 23 chromosomes and are not in pairs only
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Interphase
- A cell spends 90% of its life here
- Cell repairs, energizes, grows, prepare for reproduction and copies DNA
- Three stages
G1 (interphase stage 1)
- Grows in size
- Accumulates the building blocks (nucleotides, proteins, etc.) for chromosome duplication
What happens to the cell in Synthesis (interphase stage 2)
DNA is replicated, forming a copy or it’s chromosomes (sister chromatids)
G2 (interphase stage 3)
Restores energy and produces proteins needed for chromosomes manipulation
Mitosis stages
Prophase
Metaphase
Anaphase
Telophase
(PMAT)
Prophase
Chromosomes condense and the spindle forms.
- Chromatin condense, forming chromosomes,
- Centrioles (a structure that organizes the spindle fibers) move to both poles
- Nucleus and nuclear membrane disappears allowing the spindle fibers in
Metaphase
Chromosomes align at the center.
- Spindle fibers attach to centromere of the sister chromatids
- the spindle fibers move the sister chromatids to the metaphase plate (middle)
Anaphase
Sister chromatids are separated by..
- Spindle fibers are shorten, pulling the chromatids sisters apart, and to opposite poles.
Telophase
Chromosomes de-condense, and new nuclei form by
- The sister chromatids, now chromosomes uncondense forming chromatins
*Cell wall pinches inward - the nucleus and nuclear membrane reappear
Cytokinesis
Completes the cell division, by dividing the cell into two daughter cells
Human cell: A cleavage furrow forms in to middle of the parent cell, which pinches it inward and eventually splitting it into two daughter cells
Plant cells: A cell plate forms in the middle of the parent cell, and will eventually form as a cell wall
