Question

Which of the following is correct about Interphase? (a) It is the phase present between two successive M-phase. (b) It lasts for more than 95 per cent in the duration of cell cycle in human cell. (c) It is also known as resting phase. (d) All the above

Short answer

All the options (a), (b), (c) are correct information about Interphase in cell biology. Therefore, (d) 'All of the above' is the right choice.

Step-by-step solution

Analyzing Option (a)

Option (a) states: 'It is the phase present between two successive M-phases.' This is indeed true. The Interphase is the phase that falls between two Mitotic phases in a cell's cycle. Therefore, Option (a) is correct.

Analyzing Option (b)

Option (b) states: 'It lasts for more than 95 per cent in the duration of cell cycle in human cell.' In a 24 hour typical duration of human cell cycle, Interphase takes about 23 hours, which is more than 95% of the total duration. So Option (b) is also correct.

Analyzing Option (c)

Option (c) states: 'It is also known as resting phase.' Though named as 'resting phase', the Interphase is a period of intense activity where the cell grows and DNA is replicated in preparation for cell division. Hence, it is a bit misleading but traditionally Interphase is also known as resting phase. Therefore, Option (c) is also correct.

Key concepts

Cell Cycle

The cell cycle is a foundational concept in biology describing the sequence of events that take place in a cell leading to its division and replication. It is divided into two main phases: the interphase and the mitotic phase (M-phase). During the interphase, the cell grows, performs its designated functions, and prepares for division. The duration of the interphase is significantly longer than the mitotic phase, particularly in human cells, where it accounts for more than 95% of the cell cycle duration.

Understanding the cell cycle is paramount because it underpins the process by which organisms grow and reproduce. The regulation of the cell cycle ensures that cells divide only when necessary, which is crucial for maintaining healthy tissues and organs. Disruptions to this cycle could lead to uncontrolled cell division and potentially contribute to the development of cancer.

Mitotic Phase

The mitotic phase is a critical part of the cell cycle wherein actual cell division occurs. This phase follows the interphase and can be further subdivided into four stages: prophase, metaphase, anaphase, and telophase. During these stages, the replicated chromosomes are condensed and arranged, pulled apart, and finally segregated into two new nuclei. This phase concludes with cytokinesis, where the cell divides its cytoplasm and membrane, resulting in two genetically identical daughter cells.

The meticulous nature of the mitotic phase is essential for genetic stability, as it ensures that each daughter cell receives an exact copy of the parent's genetic material. Any error during this phase, such as improper chromosome separation, can lead to genetic disorders or cell death.

DNA Replication

DNA replication is a vital process that occurs during the interphase of the cell cycle, specifically in the S-phase (synthesis phase). This process ensures that each daughter cell receives an exact copy of the DNA. During replication, the DNA molecule unwinds and each strand serves as a template for the creation of a new complementary strand. Enzymes called DNA polymerases are instrumental in this process, as they add nucleotides to form the new strand in a highly regulated manner.

The fidelity of DNA replication is crucial for maintaining genetic integrity across generations of cells. Errors during replication can lead to mutations, which may or may not have consequences for the organism, depending on where in the genome they occur. This phase is complex and controlled by numerous mechanisms to minimize errors, safeguarding the cell's genomic stability.