Which of the following does not occur during mitosis?
a. Condensation of the chromosomes
b. Replication of the DNA
c. Separation of sister chromatids
d. Spindle formation

Verified step by step guidance

1. Understand the process of mitosis: Mitosis is the division of a eukaryotic cell's nucleus into two genetically identical nuclei. It consists of several stages: prophase, metaphase, anaphase, and telophase, followed by cytokinesis.
2. Review the key events of mitosis: During mitosis, chromosomes condense (prophase), the spindle apparatus forms (prophase), sister chromatids separate (anaphase), and the nuclear envelope reforms (telophase).
3. Recall when DNA replication occurs: DNA replication does not occur during mitosis. Instead, it occurs during the S phase of the cell cycle, which is part of interphase, prior to mitosis.
4. Analyze the options: a) Condensation of chromosomes occurs during prophase. b) Replication of DNA occurs during the S phase, not mitosis. c) Separation of sister chromatids occurs during anaphase. d) Spindle formation occurs during prophase.
5. Conclude which event does not occur during mitosis: Based on the analysis, identify that DNA replication (option b) does not occur during mitosis.

Key Concepts

Mitosis

Mitosis is a process of cell division that results in two genetically identical daughter cells from a single parent cell. It consists of several stages: prophase, metaphase, anaphase, and telophase, during which the chromosomes are condensed, aligned, separated, and finally distributed into the daughter cells.

Chromosome Condensation

Chromosome condensation occurs during prophase of mitosis, where the chromatin fibers become tightly coiled and folded, making the chromosomes visible under a microscope. This process is crucial for ensuring that the chromosomes can be accurately separated and distributed during cell division.

DNA Replication

DNA replication is the process by which a cell duplicates its DNA before mitosis begins, ensuring that each daughter cell receives an identical set of chromosomes. This process occurs during the S phase of the cell cycle, prior to the onset of mitosis, and is not a part of the mitotic process itself.