OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

How can embryonic stem cells develop into specialized cells?

1. By undergoing photosynthesis

2. By activating inactive genes

3. By absorbing nutrients from their environment

4. By cloning themselves repeatedly

The correct answer is: By activating inactive genes

Embryonic stem cells have the ability to develop into specialized cells through the process of gene activation. These stem cells are unique because they are pluripotent, meaning that they have the potential to differentiate into many different types of cells, such as muscle cells, nerve cells, or blood cells. During differentiation, certain genes relevant to the specific type of cell the stem cell is becoming are activated, while others are turned off. This selective gene activation is crucial for guiding the stem cells in their transformation into specialized forms with unique functions. For instance, the gene expression patterns that govern the development of a neuron are distinct from those of a muscle cell. This process involves complex signaling pathways and regulatory mechanisms that ensure the cells mature appropriately. The other options do not accurately describe the mechanism by which embryonic stem cells specialize. Photosynthesis is not relevant to stem cell differentiation since it pertains to how plants convert light into energy, and stem cells do not perform this process. While obtaining nutrients is important for the growth and overall health of the cells, it does not directly lead to specialization. Cloning refers to creating identical copies of organisms and doesn't constitute the process of differentiation in stem cells. Thus, the activation of inactive genes is the key process that enables embryonic stem