Unit 2: Homologous Chromosomes Versus Sister Chromatids: What's the Difference? Ch.5 Flashcards
MCB 181R University of Arizona (8 cards)
What are sister chromatids?
- Sister chromatids are present only if the cell has replicated (copied) its DNA.
- They are two identical copies of a chromosome, connected at the centromere.
- They form after DNA replication and are visible during the nuclear division (when chromosomes condense).
When do sister chromatids appear?
Sister chromatids appear after DNA replication, during the S phase of the cell cycle. They are most visible during the prophase of mitosis or meiosis when chromosomes condense.
What is the relationship between sister chromatids and a replicated chromosome?
A replicated chromosome consists of two identical sister chromatids joined together at the centromere.
What happens to sister chromatids during cell division?
During cell division (mitosis or meiosis), sister chromatids operate at the centromere and move to opposite poles of the cell, becoming individual chromosomes. This ensures that each daughter cell receives a complete set of chromosomes.
What is the difference between a chromosomes before and after DNA replication?
Before DNA replication, a chromosomes consist of a single DNA molecule. After DNA replication, it consists of two identical sister chromatids connected at the centromere.
What is the difference between Homologous Chromosomes and Sister Chromatids?
- Homologous Chromosomes: Are two distinct chromosomes that carry the same genes but are not identical.
- Sister Chromatids: Are two identical copies of the same chromosomes, connected at the centromere.
What is the structure of a replicated Chromosomes?
- Composed of two identical sister chromatids.
- Connected at the centromere.
What is the role of the centromere?
- The point of where sister chromatids are attached.
- Plays a crucial role in chromosomes segregation during cell division.
