Questions and Answers
Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II?
Of the two processes we learned about, which is going on in my hand right now?
mitosis
What process goes on continuously in most parts of the body?
mitosis
In which location does meiosis take place?
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If you look through a microscope and see a cell with chromosomes lined up two by two, what stage of cellular reproduction must you be looking at?
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What is the only time that chromosomes line up by homologous pairs?
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What structure is represented by the waist where two twin chromosomes are joined?
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What is the point of attachment between two sister chromatids of a duplicated chromosome?
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How many chromosomes will one of the body cells contain just before mitosis begins if one gamete contains 5 chromosomes?
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What stage of the life cycle must a cell be in if chromosomes are photographed?
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Which processes lead to most genetic variation in sexually reproducing organisms?
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Which of these gametes contains one or more recombinant chromosomes?
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How is meiosis II similar to mitosis?
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If the DNA content of a diploid cell in the G1 phase is x, what will be the DNA content at metaphase of meiosis I?
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If the DNA content of a diploid cell is x in the G1 phase and 2x at metaphase of meiosis I, what will it be at metaphase of meiosis II?
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What type of cell contains 22 autosomes and a Y chromosome?
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During which phase do the two homologs of a pair move toward opposite poles of the dividing cell?
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Homologous pairs of chromosomes are lined up independently of other such pairs during which phase?
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Crossing over occurs between which chromosomes?
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In human gamete production, what is the average number of crossover events per chromosome pair?
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Which of these gametes contain one or more recombinant chromosomes?
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Study Notes
Meiosis Overview
- Parent cell in meiosis is diploid; results in four haploid daughter cells.
- DNA content is halved during both meiosis I and meiosis II.
- Ploidy changes from diploid to haploid in meiosis I; remains haploid in meiosis II.
Cell Division Types
- Mitosis occurs continuously in most body parts; responsible for growth and repair.
- Meiosis occurs exclusively in gonads; facilitates gamete production.
Stages of Meiosis
- Observing chromosomes lined up two by two indicates meiosis I.
- Homologous chromosomes align in pairs only during meiosis I.
Chromosomal Structure
- Centromere is the structure that connects sister chromatids in a duplicated chromosome.
- It serves as the point of attachment during cell division.
Hypothetical Organisms
- An organism's gamete with 5 chromosomes suggests body cells contain 10 chromosomes before mitosis begins.
Genetic Variation
- Most genetic variation in sexually reproducing organisms results from crossing over, random fertilization, and independent assortment during meiosis.
- Crossover events average 2-3 per chromosome pair in human gamete production.
Anaphase and Metaphase
- In meiosis II, sister chromatids separate during anaphase, similar to the process in mitosis.
- During metaphase I, homologous pairs align independently, enhancing genetic diversity.
Recombinant Chromosomes
- Gametes B and C, as well as B, C, F, and G, contain recombinant chromosomes, indicative of genetic recombination through crossing over.
- Crossing over occurs between nonsister chromatids of homologous chromosomes, contributing to variability.
DNA Content Calculations
- The DNA content of a diploid cell in G1 phase is x; at metaphase of meiosis I, it is 2x.
- The DNA content at metaphase of meiosis II will not be x or 0.5; precise value not disclosed.
Human Sperm Identification
- A human cell with 22 autosomes and a Y chromosome represents a sperm cell, highlighting its haploid nature post-meiosis.
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Description
This quiz covers the essential processes of meiosis, including the stages involved and the genetic implications. Learn about the differences between meiosis and mitosis, the chromosomal structure, and the significance of genetic variation. Ideal for students studying biology topics related to cell division.
