Question

Cell Cycle:  Events

Name the cell cycle stage in which each event takes place.  Each answer choice is used once and only once.

1.    Each chromosome is duplicated. 2. The cell divides into two daughter cells. 3. Cell contents, except for chromosomes, are duplicated. 4. Chromatids are separated from each other forming two identical nuclei. 5. The majority of the cell's life, when it is not actively engaged in chromosomal or cellular divsion. 6. The cell double-checks duplicated chromosomes and makes any needed repairs.

A. Cytokinesis B. G1 C. G2 D. Interphase E. Mitosis F. S

Answer 1

The cell cycle is composed of interphase, and mitosis. Interphase has three phases- Go, G1, G2 and S phase. In Go phase, the cell is quiescent. The cell enters G1 phase during start of cell division. In G1 phase, all components of the cell are duplicated such as cytoplasm, organelles, etc. However, there is no DNA replication seen. Hence, chromosomes are not duplicated in G1 stage. In S phase, there is DNA replication occurring. Thus, chromosomes are duplicated in the cell. Thus, there will be 96 chromosomes in human cell. In G2, phase, although there is RNA, and protein synthesis, the cell will check the duplicated chromosomes for error. All errors in DNA are then repaired in this stage. In mitosis, there will be condensation of chromosomes, followed by mitotic spindle formation, migration to the poles and then separation of chromosomes in daughter cells. The daughter cells will separate in cytokinesis, where cell division is observed.

Right choice:

Event	Right choice
1. Each chromosome is duplicated.	F. S
2. The cell divides …. daughter cells.	A. Cytokinesis
3. Cell contents, ….. duplicated.	B. G1
4. Chromatids are separated …. identical nuclei.	E. Mitosis
5. The majority of the cell's life, …… cellular division.	D. Interphase
6. The cell double-checks …… needed repairs.	C. G2