For the human cells listed in the table, it takes about 12 hours to copy the genetic material, get ready to divide, and undergo division. However, as the table shows, the life span of each cell type differs.

Question

Cell Type Average Life Span
Skin cell 2 weeks
Liver cell 300-500 days
Red blood cell 4 months
Which part of the cell cycle is most likely responsible for the varying cell life spans?

A.
the G1 phase

B.
the S phase

C.
the G2 phase

D.
the M phase

Multiple Choice Question
Part B:

Which best supports the choice in Part A?

A.
The time spent during cell growth is dependent on the cell type.

B.
The time spent during DNA replication is dependent on the cell type.

C.
The time spent preparing for mitosis is dependent on the cell type.

D.
The time spent in mitosis is dependent on the cell type.

Answer 1

Part A:

The part of the cell cycle most likely responsible for the varying cell life spans is:

A. the G1 phase

Part B:

The best support for the choice in Part A is:

A. The time spent during cell growth is dependent on the cell type.

Explanation: The G1 phase (the first gap phase) is a period of cell growth before DNA replication begins. The duration of the G1 phase can vary significantly among different cell types, leading to differences in the overall cell life span. For instance, skin cells might have a shorter G1 phase due to their rapid turnover, while liver cells might take a longer time. The S phase is generally consistent for cells that are dividing, while the G2 and M phases also tend to be shorter in comparison to the G1 phase.