After S phase, what makes up a single chromosome?a. two daughter chromosomesb. a double-stranded DNA moleculec. two single-stranded DNA moleculesd. two sister chromatids

Verified step by step guidance

1. Understand that the S phase is part of the cell cycle where DNA replication occurs.
2. During the S phase, each chromosome is duplicated, resulting in two identical copies.
3. These identical copies are known as sister chromatids.
4. Each sister chromatid consists of a double-stranded DNA molecule.
5. After the S phase, a single chromosome is composed of two sister chromatids joined at the centromere.

Key Concepts

Chromosome Structure

A chromosome is a structure within cells that contains DNA and proteins. After the S phase of the cell cycle, each chromosome consists of two identical halves called sister chromatids, which are joined at a region known as the centromere. This structure is crucial for ensuring accurate DNA replication and distribution during cell division.

S Phase of the Cell Cycle

The S phase, or synthesis phase, is a part of the cell cycle where DNA replication occurs. During this phase, each chromosome is duplicated, resulting in two sister chromatids for each original chromosome. Understanding the S phase is essential for grasping how genetic material is prepared for cell division.

Sister Chromatids

Sister chromatids are the two identical copies of a single chromosome that are formed during DNA replication in the S phase. They remain attached at the centromere until they are separated during mitosis or meiosis. Recognizing the role of sister chromatids is vital for understanding the mechanics of chromosome segregation during cell division.