Answer the questions that follow for each stage of the cell cycle (G1, S, G2, prophase, metaphase, anaphase, telophase). If necessary, use an arrow to indicate a change that occurs during a particular cell cycle stage (for example, 1→ 2 or yes → no). a. How many chromatids comprise each chromosome during this stage? b. Is the nucleolus present? c. Is the mitotic spindle organized? d. Is the nuclear membrane present?

Answer: the answer is based on 46 chromosomes assuming humans.

G1.

Chromatids: 46 chromosomes / 46 chromatid.

Nucleolus: yes. only disappears during mitosis (RNA synthesis is crucial for making proteins all the time)

Mitotic spindle: no. only appears during mitosis.

Nuclear membrane: yes. only disappears during mitosis.

S. DNA replication occurs.

Chromatids: 46 chromosome / 92 chromatids

Nucleolus: yes

Mitotic spindle: no

Nuclear membrane: yes

G2

Chromatids: 46 chromosome / 92 chromatids

Nucleolus: yes

Mitotic spindle: no

Nuclear membrane: yes

Prophase:

Chromatids: 46 chromosome / 92 chromatids

Nucleolus: will disintegrate at the beginning of the phase.

Mitotic spindle: starts to arrange at the beginning of the phase.

Nuclear membrane: starts dissolving at the beginning of the phase.

metaphase, (chromosomes appear in the middle)

Chromatids: 46 chromosome / 92 chromatids

Nucleolus: no

Mitotic spindle: arranges chromosomes in the middle.

Nuclear membrane: no

anaphase, sister chromatids split and move to either poles of the cell

Chromatids: 92 chromosome / 92 chromatids)

Nucleolus: no

Mitotic spindle: starts to disassemble during early telophase.

Nuclear membrane: no

telophase at the end of telophase when the cytoplasm finally splits

Chromatids: 46 chromosome / 46 chromatids per cell

Nucleolus: yes

Mitotic spindle: starts to disassemble during early telophase.

Nuclear membrane: will start to form at the end of telophase.

Remember that is a continuous process it has been named in 4 phases by humans to study it.