Skin cells
A. have terminally differentiated
B. are stem cells
C. become senescent quickly
D. become quiescent quickly
A. have terminally differentiated
Skin cells are typically terminally differentiated cells, which means that they have reached a mature state and can no longer divide or differentiate into other cell types. Therefore, the correct answer is A. Skin cells, such as keratinocytes, have undergone a process of differentiation to become specialized cells that make up the outer layer of the skin.
Stem cells, on the other hand, are undifferentiated cells with the ability to self-renew and differentiate into various specialized cell types. Skin does have a small population of stem cells, known as skin stem cells, which are responsible for replenishing the skin's cells and maintaining its integrity. However, the majority of skin cells are terminally differentiated.
Skin cells do not become senescent (answer C) quickly. Senescence refers to a state of irreversible growth arrest that cells enter into as a response to various stresses or as a consequence of aging. While skin cells can undergo senescence over time, it is not a rapid process.
Skin cells also do not become quiescent (answer D) quickly. Quiescence refers to a state of reversible growth arrest, where cells temporarily stop dividing but can resume proliferation when needed. Skin cells, specifically the basal layer of the skin, which contains the stem cells, have the ability to enter a quiescent state when new cell production is not required. However, this is not a quick process and is regulated depending on the skin's needs.
The correct answer is A. Skin cells have terminally differentiated.
To arrive at this answer, let me break down the options for you:
Option B: Stem cells are undifferentiated cells that have the potential to develop into different cell types. However, skin cells are not considered stem cells because they have already gone through the process of differentiation and have specialized into a particular cell type.
Option C: Senescence refers to the state of irreversible cell cycle arrest that occurs as cells age or experience damage. While skin cells do age and undergo changes over time, it wouldn't be accurate to say that they become senescent quickly. The rate of senescence can vary across different cell types, but it is not a defining characteristic of skin cells.
Option D: Quiescence refers to a state of temporary inactivity, where cells enter a reversible and non-dividing phase. While skin cells can enter a quiescent state under certain circumstances (such as during wound healing), it is not accurate to say that they become quiescent quickly as a general characteristic of skin cells.
Option A: Skin cells have terminally differentiated, which means they have matured and become specialized into a specific cell type. In the case of skin cells, they differentiate into various types like epidermal cells, hair cells, sweat gland cells, etc. Terminally differentiated cells have undergone changes in gene expression and cellular structure that prevent them from dividing and becoming different cell types. Therefore, this option best describes the characteristics of skin cells.