Final answer:
DNA supercoiling is crucial for compacting DNA to fit within a cell, facilitates DNA replication and transcription, and helps regulate gene expression by affecting the accessibility of genes.
Step-by-step explanation:
The importance of DNA supercoiling for cell survival is multifaceted. Supercoiling plays a critical role in DNA compaction, allowing the long DNA molecules to fit within the limited space of the cell. In the context of the options provided, supercoiling facilitates DNA replication and transcription (C), as it creates the compact structure that can be more easily managed during these processes. Supercoiling, through the action of enzymes like topoisomerases, helps the cell to manage the stress and strain on the DNA molecule as it unwinds during replication and transcription. This protective mechanism prevents the DNA from becoming too tightly wound or overwound, which can lead to breaks and potentially lethal damage. Additionally, supercoiling is involved in regulating gene expression (B) as the degree of supercoiling can influence the accessibility of genes to be transcribed.
DNA supercoiling is important for cell survival because it plays several essential roles in the functioning of cells. Firstly, supercoiling stabilizes the structure of DNA, preventing it from becoming tangled or damaged. Secondly, supercoiling regulates gene expression by controlling the accessibility of genes to transcription factors. Lastly, supercoiling facilitates DNA replication and transcription by allowing the DNA strands to unwind and separate efficiently. Without supercoiling, cells would struggle to package and maintain their DNA, leading to DNA damage and impaired cellular functions.