A Level Biology Practice Exam

What does differentiation in cellular biology entail?

1. Identical replication of cells

2. Selective expression of genes in a genome

3. Process of cell deconstruction

4. Random genetic variation

The correct answer is: Selective expression of genes in a genome

Differentiation in cellular biology refers to the process where unspecialized cells become specialized in structure and function. This occurs through the selective expression of genes in a genome. During differentiation, specific genes are turned on or off, leading to the production of proteins that define the characteristics and functions of different cell types, such as muscle cells, nerve cells, or skin cells. The ability of a single cell, such as a stem cell, to develop into various specialized cells illustrates the importance of gene regulation in this process. Each specialized cell has a unique set of functional capacities which arise from this selective gene expression. In contrast, identical replication of cells does not involve differentiation; it simply refers to the process of mitosis where a cell divides to produce two genetically identical daughter cells. The process of cell deconstruction does not relate to differentiation and suggests breakdown rather than specialization. Lastly, random genetic variation is associated with processes like mutation and sexual reproduction, but it does not inherently involve the specific pathway of cellular differentiation that leads to specialized cell types.