school slide Flashcards
What is meiosis?
A type of cell division that reduces the chromosome number by half, resulting in four haploid daughter cells.
How many nuclear divisions occur during meiosis?
Two nuclear divisions.
What is the chromosome number in daughter cells after meiosis?
Half of the number of chromosomes as the parent cell.
What are the two stages of meiosis?
- Meiosis I
- Meiosis II
What is another name for Meiosis I?
Reductional Division
What is another name for Meiosis II?
Equational Division
What occurs during interphase before meiosis?
Cell growth and DNA replication.
What are the three phases of meiotic interphase?
- G1 phase
- S phase
- G2 phase
What happens during the G1 phase?
Cell growth.
What occurs during the S phase?
DNA replication.
What is the purpose of the G2 phase?
Preparation for meiosis.
What happens during Prophase I?
Homologous chromosomes pair up and crossing over occurs.
How long does Prophase I last compared to Prophase in mitosis?
It takes about 85 - 95 percent of the total time for meiosis.
What are the five substages of Prophase I?
- Leptotene
- Zygotene
- Pachytene
- Diplotene
- Diakinesis
What occurs during the leptotene stage?
Chromatin condenses to form chromosomes.
What is synapsis?
The pairing of homologous chromosomes.
What is formed at the completion of the zygotene stage?
Bivalents.
What occurs during the pachytene stage?
Crossing over occurs.
What is a tetrad?
A group of four sister chromatids.
What happens during the diplotene stage?
DNA recombination is complete.
What is the significance of diakinesis?
Chromosomes become shorter and thicker due to condensation.
What occurs during Metaphase I?
All bivalents align at the metaphase plate.
What happens during Anaphase I?
Homologous chromosomes move to opposite poles.