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2. A rapidly dividing human cell completes the cell cycle in about 24 hours. The table below shows the amount of time that a cell typically spends in each phase of the cell cycle. Assume that the cell starts its cell cycle at midnight and completes cytokinesis at midnight of the following day.

Determine the time of day at which the cell completes each phase. Calculate the percentage of time the cell spends in each phase using the following formula:

[tex]\[ \text{Percentage of time in phase} = \left(\frac{\text{hours spent in phase}}{24 \text{ hours}}\right) \times 100 \][/tex]

Record your answers in Table 1 below. (4 points)

Table 1: Cell Cycle of a Human Cell
\begin{tabular}{|c|c|c|c|c|}
\hline \begin{tabular}{l}
Phase of cell \\
cycle
\end{tabular} & [tex]$G_1$[/tex] & S & [tex]$G_2$[/tex] & M \\
\hline \begin{tabular}{l}
Hours spent in \\
phase
\end{tabular} & 11 & 8 & 4 & 1 \\
\hline \begin{tabular}{l}
Time when \\
phase ends
\end{tabular} & 11:00 AM & 7:00 PM & 11:00 PM & Midnight \\
\hline \begin{tabular}{l}
Percentage of \\
total time in \\
phase
\end{tabular} & 45.83\% & 33.33\% & 16.67\% & 4.17\% \\
\hline
\end{tabular}

3. Use the data table to label your clock with the four phases of the cell cycle: [tex]$G_1, S$[/tex], [tex]$G_2$[/tex], and M. (1 point)



Answer :

GinnyAnswer
To solve this problem, we need to determine the time each phase of the cell cycle ends and calculate the percentage of time the cell spends in each phase.

### Hours spent in each phase:
- [tex]\( G_1 \)[/tex]: 11 hours
- [tex]\( S \)[/tex]: 8 hours
- [tex]\( G_2 \)[/tex]: 4 hours
- [tex]\( M \)[/tex]: 1 hour

### Total hours in a day:
- 24 hours

### Step-by-Step Solution

1. Calculate the ending time for each phase:

- End of [tex]\( G_1 \)[/tex] phase:
Since the [tex]\( G_1 \)[/tex] phase starts at midnight (00:00) and lasts for 11 hours, it will end at:
[tex]\[ \text{End of } G_1 = 00:00 + 11 \text{ hours} = 11:00 \][/tex]

- End of [tex]\( S \)[/tex] phase:
The [tex]\( S \)[/tex] phase starts right after [tex]\( G_1 \)[/tex] ends. It begins at 11:00 and lasts for 8 hours:
[tex]\[ \text{End of S} = 11:00 + 8 \text{ hours} = 19:00 \][/tex]

- End of [tex]\( G_2 \)[/tex] phase:
The [tex]\( G_2 \)[/tex] phase starts right after [tex]\( S \)[/tex] ends. It begins at 19:00 and lasts for 4 hours:
[tex]\[ \text{End of } G_2 = 19:00 + 4 \text{ hours} = 23:00 \][/tex]

- End of [tex]\( M \)[/tex] phase:
The [tex]\( M \)[/tex] phase starts right after [tex]\( G_2 \)[/tex] ends. It begins at 23:00 and lasts for 1 hour:
[tex]\[ \text{End of M} = 23:00 + 1 \text{ hour} = 24:00 \text{ (or midnight)} \][/tex]

2. Calculate the percentage of time spent in each phase:

- Percentage of time in [tex]\( G_1 \)[/tex]:
[tex]\[ \text{Percentage of } G_1 = \left( \frac{11 \text{ hours}}{24 \text{ hours}} \right) \times 100 = 45.83\% \][/tex]

- Percentage of time in [tex]\( S \)[/tex]:
[tex]\[ \text{Percentage of } S = \left( \frac{8 \text{ hours}}{24 \text{ hours}} \right) \times 100 = 33.33\% \][/tex]

- Percentage of time in [tex]\( G_2 \)[/tex]:
[tex]\[ \text{Percentage of } G_2 = \left( \frac{4 \text{ hours}}{24 \text{ hours}} \right) \times 100 = 16.67\% \][/tex]

- Percentage of time in [tex]\( M \)[/tex]:
[tex]\[ \text{Percentage of } M = \left( \frac{1 \text{ hour}}{24 \text{ hours}} \right) \times 100 = 4.17\% \][/tex]

### Completed Table 1:

[tex]\[ \begin{array}{|c|c|c|c|c|} \hline \text{Phase of cell cycle} & G_1 & S & G_2 & M \\ \hline \text{Hours spent in phase} & 11 & 8 & 4 & 1 \\ \hline \text{Time when phase ends} & 11:00 & 19:00 & 23:00 & 24:00 \\ \hline \text{Percentage of total time in phase} & 45.83\% & 33.33\% & 16.67\% & 4.17\% \\ \hline \end{array} \][/tex]

### Clock Labeling:

You can now use the time intervals and percentages to label the clock as follows:
- [tex]\( G_1 \)[/tex] phase from midnight (00:00) to 11:00 (45.83% of the cycle)
- [tex]\( S \)[/tex] phase from 11:00 to 19:00 (33.33% of the cycle)
- [tex]\( G_2 \)[/tex] phase from 19:00 to 23:00 (16.67% of the cycle)
- [tex]\( M \)[/tex] phase from 23:00 to midnight (24:00) (4.17% of the cycle)

This completes the step-by-step solution for both determining the end times and calculating the percentages for each phase in the cell cycle.