Questions and Answers
What is meiosis?
What happens during interphase?
A period of normal growth and existence of the cell; DNA replicates during S phase.
What occurs during prophase I?
Copied DNA starts to coil into visible chromosomes connected by centromeres; homologous chromosomes pair up.
What is crossing over?
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What are homologous chromosomes?
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Describe metaphase I.
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What happens during anaphase I?
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What occurs in telophase I?
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What is cytokinesis?
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Explain prophase II.
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What happens during metaphase II?
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What is the outcome of anaphase II?
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Describe telophase II.
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What is a haploid cell?
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What is a diploid cell?
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What is a sister chromatid?
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Study Notes
Overview of Meiosis
- Meiosis is a type of cell division that produces four haploid gametes from one diploid cell.
- It consists of two sequential divisions: meiosis I and meiosis II.
Interphase
- Interphase is the cell's growth phase, where it prepares for division.
- DNA replication occurs during the S phase of interphase.
Meiosis I
- Prophase I: DNA coils into visible chromosomes, homologous chromosomes pair up.
- Crossing Over: During prophase I, homologous chromosomes exchange genetic information, increasing genetic variation.
- Metaphase I: Chromosomes line up in the center of the cell; spindle fibers attach to centromeres.
- Anaphase I: Spindle fibers pull homologous chromosomes to opposite ends of the cell.
- Telophase I: Nuclear membranes form around the separated chromosomes; cytokinesis divides the cell into two diploid cells.
Meiosis II
- Prophase II: Nuclear membranes dissolve again; spindle fibers re-form in each diploid cell.
- Metaphase II: Chromosomes line up in the center of each cell; spindle fibers attach to centromeres.
- Anaphase II: Sister chromatids are pulled apart, moving towards opposite poles of each cell.
- Telophase II: Nuclear membranes form around each set of chromosomes; cytokinesis results in four haploid cells.
Key Cell Types
- Haploid Cell: Contains one set of chromosomes; examples include egg and sperm cells.
- Diploid Cell: Contains two sets of chromosomes, one from each parent; humans have 32 pairs of chromosomes.
Chromosome Structure
- Sister Chromatid: Identical copies of a chromosome joined by a centromere; formed during the S phase and separated during meiosis II.
Summary of Meiosis Phases
- Interphase sets the stage for meiosis through DNA replication.
- Meiosis I focuses on separating homologous chromosomes.
- Meiosis II separates sister chromatids to create four haploid cells capable of fertilization.
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Description
Test your knowledge on meiosis, a crucial process of cell division that leads to the formation of gametes. This quiz covers interphase, meiosis I and II stages, and the importance of crossing over in genetic variation.