Cell Division

Shelby Schoffstall

Cell Cycle

Mitosis

Meiosis

Phase of Cell Cycle

The phases of cell cycle are G1-S-G2-M.

The G1 stage stands for "GAP 1". The S stage stands for "Synthesis". This is the stage when DNA replication occurs. The G2 stage stands for "GAP 2". The M stage stands for "mitosis", and is when nuclear (chromosomes separate) and cytoplasmic (cytokinesis) division occur.




Phases of Mitosis

Prophase

The DNA molecules progressively shortenand condense by coiling, to form chromosomes. The nuclear membrane and nucleolus are no longer visible.

The spindle apparatus has migrate to opposite poles of the cell



Phases of Mitosis

Metaphase

The spindle fibres attach themselves to the centromeres of the chromosomes and align the the chromosomes at the equatorial plate.


Phases of Mitosis

Anaphase

The spindle fibres shorten and the centromere splits, separated sister chromatids are pulled along behind the centromeres.


Phases of Mitosis

Telophase

The chromosomes reach the poles of their respective spindles. Nuclear envelope reform before the chromosomes uncoil. The spindle fibers disintegrate.


Phases of Meiosis

1. Prophase IHomologous chromosomes pair up and form tetrad

2. Anaphase ISpindle fibers move homologous chromosomes to opposite sides

3. Telophase IINuclear membrane reforms, cytoplasm divides, 4 daughter cells formed

4. Metaphase IIChromosomes line up along equator, not in homologous pairs

5. Prophase ICrossing-over occurs

6. Anaphase IIChromatids separate

7. Metaphase IHomologs line up alone equator

8. Telophase ICytoplasm divides, 2 daughter cells are formed

QUIZ cell cycle

1. __________ only occur(s) in the gonads to produce gametes. Mitosis
1. Meiosis
2. Mitosis and meiosis
3. Sporogony
4. Schizogony

2. Which of the following is mitosis not used for? Repair (of a wound) in multicellular 1. organisms
2. Asexual reproduction in unicellular organisms
3. Development (e.g., baby in mother's womb)
4. Production of gametes
5. All of the above use mitosis

3. During which stage of mitosis do the centromeres split?

1. Prophase
2. Interphase
3. Anaphase
4. Telophase
5. Synthesis stage

4. During which stage of mitosis does cytokinesis usually occur in animals?

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
5. Interphase

5. What is the correct order of the stages of mitosis?
1-Metaphase 2-Telophase 3-Anaphase 4-Prophase

1. 4,1,2,3
2. 2,3,1,4
3. 1,2,3,4
4. 1,3,2,4
5. 4,1,3,2

6. During which stage of meiosis do the sister chromatids begin to move toward the poles?

1. Prophase I
2. Telophase I
3. Anaphase II
4. Anaphase I
5. Telophase II

7. During which stage of meiosis do tetrads line up at the equator?

1. Metaphase I
2. Telophase I
3. Metaphase II
4. Anaphase II
5. Anaphase I

8. In both mitosis and meiosis, sister chromatids seperate during anaphase, but there are _____ haploid daughter nuclei produced by meiosis compared to ______ diploid nuclei by mitosis.

1. 6,3
2. 4,2
3. 2,4
4. 3,6
5. 9,1

9. During which stage of mitosis does the nuclear envelope begin to disappear?

1. Metaphase I
2. Telophase I
3. Anaphase II
4. Prophase I
5. Metaphase II

10. When _______________ occurs between nonsister chromatids genetic exchange between chromosomes provides new combination of genes that are different from either parent.

1. cytokinesis
2. crossing-over
3. mitosis
4. cell division
5. centromeres splitting