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From DNA to blood type: - Coggle Diagram

- - - - Stage 2 - Prophase:
        During prophase, condensin is recruited by the chromosomes, and the condensation process begins, which will last until metaphase; In multiple species during this stage, cohesin is mainly eliminated from the arms of the sister chromatids, causing the individual sister chromatids to be separated. The eliminated cohesin will still be retained at the centromere; As the two pairs of centrioles travel to opposing poles and microtubules begin to polymerize from the duplicated centrosomes, the spindle begins to develop.
        
        Stage 3 - Prometaphase:
        Starts with the fragmentation of the nuclear envelope into many small vesicles, these vesicles will be divided between the daughter cells; The breakdown of the nuclear membrane will also be a key step for spindle assembly since in animal cells the centrosomes are located outside of the nucleus so in order for the microtubules of the developing spindle to have access to the chromosomes the breakdown of the membrane is needed; As they expand out of the centrosomes, microtubules rapidly build and disintegrate, looking for attachment sites at chromosomal kinetochores, which are complex platelike structures that develop during prometaphase on one face of each sister chromatid near its centromere. As prometaphase progresses, microtubules sprouting from both poles of the spindle pull and tug on chromosomes in opposite directions, until the pole-directed pressures are eventually balanced. Sister chromatids do not separate during this tug-of-war because they are held together by the cohesin that remains at their centromeres. At the conclusion of prometaphase, chromosomes are bi-oriented, which means that the kinetochores on sister chromatids are attached to opposing poles of the spindle via microtubules.
        
        Stage 4 - Metaphase:
        When the centromeres of all the cell's chromosomes line up exactly at the equator of the spindle chromosomes takes their most compacted form; Some chromosomes stop moving temporarily during this phase since cells can be experimentally arrested with miotic poisons such as colchicine; To enter the next stage, anaphase, the spindle of the cells needs to be properly assembled and a complex checkpoint mechanism is responsible for checking this.
        
        Stage 5 - Anaphase:
        The advancement of cells from metaphase towards anaphase is marked by the separation of sister chromatids the main reason why this separation happens is that the protease degrades the cohesin molecules that connect the sister chromatids precipitously; This separation causes one chromatid to be pushed towards one side and the other to be pushed towards the opposite side.
        
        Stage 6 - Telophase:
        The end of mitosis, the stage where the chromosomes reach the poles; The nuclear membrane recovers and the chromosomes begin to decondense into their interphase conformations; Cytokinesis, or the division of the cytoplasm into two daughter cells with the exact same genetic composition, occurs after telophase.
        
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        Drawings:
  - - - Meiosis I
        
        Prophase: Homologous chromosomes pair and exchange their DNA in a process known as homologous recombination resulting many times in chromosomal hybrid; The new combination of DNA is an essential source of hereditary variation and will result in new mixes of alleles; Bivalents or quadruplicates are the names of the newly combined and duplicated chromosomes which have four chromatids and two chromosomes, one chromosome originates from each parent; Synapsis is known as the pairing of the homologous chromosomes and at this stage, non-sister chromatids traverse at areas classified as chiasmata.
        
        Metaphase: Chromosomes line up exactly at the equator of the spindle; The centrioles are now located at the opposite sides of the cells and the meiotic spindle extends from them. The spindle fibers also attach to one chromosome of each pair.
        
        Anaphase: Homologous chromosomes are pulled to opposite poles since the kinetochore microtubules become short; The Nonkinetochore microtubules extend, causing the centrosomes to be pushed even further apart and the cells stretch for division down the center; The sister chromatids are unable to stay together while the homologs are segregated.
        
        Telophase and Cytokinesis: At opposite sides of the cells, fulls sets of chromosomes assemble, and a membrane forms around each one of them forming new nuclei; Then the process of cytokinesis occurs as the single cell divides into two daughter cells. The cell is divided exactly in the middle and since each set of chromosomes now have a nucleus and membrane they are the daughter cells.
        
        Drawing:
        
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      - Meiosis II
        
        Anaphase: It occurs immediately after the cytokinesis when the daughter cells are formed in meiosis one; Each one of the daughter cells now has 23 chromosomes that are condensed into X-shaped structures; In this stage, the chromosomes start to condense while the dissolution of the nuclear membrane and the disappearance of the Golgi apparatus occurs; Since the membrane dissolves the chromosomes are released; Spindle fibers reform and attach themselves to centromeres.
        
        Metaphase: The microtubules connect the chromosomes to the centriole poles at the kinetochores of sister chromatids; The metaphase plate is formed when the chromosomes align at the equator.
        
        Anaphase: The centromeres of each chromosome divide at the same time and the sister chromatids are pushed away from each other towards the opposing poles; The kinetochore is at the leading edge as the chromatids travel towards the poles, with the chromosomal arms trailing.
        
        Telophase and Cytokinesis: The chromosomes recombine into an undifferentiated mass, and a nuclear membrane forms surrounding it; Telophase II, which is followed by cytokinesis, signals the conclusion of meiosis by resulting in the formation of four haploid daughter cells.
- - - - DNA polymerases: Responsible for synthesizing new DNA molecules by adding nucleotides into the leading and lagging DNA strands.
        
        Topoisomerase or DNA Gyrase : Responsible for unwinding and rewinding DNA strands in order to prevent the DNA from becoming tangled or supercoiled.
        
        Exonucleases: A group of enzymes responsible for removing nucleotide bases from the end of a DNA chain.
        
        DNA ligase: Joins DNA fragments together by forming phosphodiester bonds between nucleotides.