Cell Division

Alexis McVeigh

Cell Cycle

Mitosis

Meiosis

Cell Cycle Phases

The phases 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

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


Phases of Mitosis

2. Metaphase: The spindle fibers attach themselves to the centromeres of the chromosomes and align the the chromosomes at the equatorial plate.

Phases of Mitosis

3. Anaphase: The spindle fibers shorten and the centromere splits, separated sister chromatids are pulled along behind the centromeres.


Phases of Mitosis

4. 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 I: Homologous chromosomes pair up and form tetrad

2. Anaphase I: Spindle fibers move homologous chromosomes to opposite sides

3. Telophase II: Nuclear membrane reforms, cytoplasm divides, 4 daughter cells formed

4. Metaphase II: Chromosomes line up along equator, not in homologous pairs

5. Prophase I: Crossing-over occurs

6. Anaphase II: Chromatids separate

7. Metaphase I: Homologs line up alone equator

8. Telophase I: Cytoplasm divides, 2 daughter cells are formed


QUIZ

Cell cycle:


1. The stage of the cell cycle where each chromosome is composed of two chromatids in preparation for mitosis.


A.G1

B.S

C.M

D.G2



2. The stage of the cell cycle where the cell is preparing to begin DNA replication is called:


a.G1

b.G2

c.S

d.M



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

a. Prophase
b. Interphase
c. Anaphase
d. Telophase
e. Synthesis stage


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

a. Prophase
b. Metaphase
c. Anaphase
d. Telophase
e. Interphase


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

a. 4,1,2,3
b. 2,3,1,4
c. 1,2,3,4
d. 1,3,2,4
e. 4,1,3,2


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

a. Prophase I
b. Telophase I
c. Anaphase II
d. Anaphase I
e. Telophase II


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

a. Metaphase I
b. Telophase I
c. Metaphase II
d. Anaphase II
e. 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.

a. 6,3,
b. 4,2
c. 2,4
d. 3,6
e. 9,1


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

a. Metaphase I
b. Telophase I
c. Anaphase II
d. Prophase I
e. Metaphase II


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

a. cytokinesis
b.crossing-over
c. mitosis
d. cell division
e. centromeres splitting