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 correct answer 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:

• G1 phase is the first phase of interphase where the cell grows and prepares for DNA replication. The length of this phase can vary significantly among different cell types, contributing to their overall life spans.
• S phase is when DNA is replicated. While important, it's generally uniform in duration across cells compared to the variability seen in G1 phase length.
• G2 phase occurs after DNA replication and is primarily focused on preparing for mitosis.
• M phase is when mitosis occurs and typically takes a relatively short and consistent amount of time.

Cell types have different requirements and capacities for growth, which influences how long they remain in the G1 phase, thereby affecting their overall life span.