Podcast
Questions and Answers
During which phase of meiosis does crossing over occur, and what is its significance?
During which phase of meiosis does crossing over occur, and what is its significance?
- Metaphase I; ensures proper chromosome alignment.
- Telophase II; reduces the chromosome number.
- Anaphase II; separates sister chromatids.
- Prophase I; increases genetic variation by exchanging genetic material. (correct)
Meiosis results in two diploid cells, while mitosis results in four haploid cells.
Meiosis results in two diploid cells, while mitosis results in four haploid cells.
False (B)
What is the significance of independent assortment in meiosis, and during which phase does it occur?
What is the significance of independent assortment in meiosis, and during which phase does it occur?
Independent assortment increases genetic variation by randomly aligning chromosome pairs during Metaphase I.
A cell with a full set of chromosomes is referred to as ______, while a cell with half the number of chromosomes is referred to as ______.
A cell with a full set of chromosomes is referred to as ______, while a cell with half the number of chromosomes is referred to as ______.
Match each chromosomal mutation with its correct description:
Match each chromosomal mutation with its correct description:
How many autosomes are present in a typical human somatic cell?
How many autosomes are present in a typical human somatic cell?
Sister chromatids separate during Anaphase I of meiosis.
Sister chromatids separate during Anaphase I of meiosis.
Explain the process of random fertilization and its contribution to genetic diversity.
Explain the process of random fertilization and its contribution to genetic diversity.
Flashcards
What is Meiosis?
What is Meiosis?
Cell division that creates sperm and egg cells (gametes).
What does haploid mean?
What does haploid mean?
Having half the usual number of chromosomes (n); in humans, 23.
What does diploid mean?
What does diploid mean?
Having the full set of chromosomes (2n); in humans, 46.
What are homologous chromosomes?
What are homologous chromosomes?
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What happens during crossing over?
What happens during crossing over?
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Explain independent assortment.
Explain independent assortment.
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What is duplication?
What is duplication?
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What is deletion?
What is deletion?
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Study Notes
- Meiosis is the cell division process that produces sex cells (gametes).
- Gametes are haploid cells with 23 chromosomes.
- Somatic cells are diploid cells with 46 chromosomes.
- Meiosis starts with one diploid cell and ends with four genetically unique haploid cells.
Chromosomes & Genetic Variation
- Humans have 23 pairs of chromosomes, totaling 46.
- 22 pairs of chromosomes are autosomes.
- One pair of chromosomes are sex chromosomes (XX for female, XY for male).
- Homologous chromosomes are pairs that contain the same genes with potentially different versions (alleles).
- Gene locus refers to the specific location of a gene on a chromosome.
Meiosis vs. Mitosis
- Meiosis produces gametes, while mitosis produces body cells.
- Meiosis involves two cell divisions, whereas mitosis involves one.
- Meiosis results in four cells, and mitosis results in two cells.
- Meiosis introduces genetic variation through crossing over and independent assortment; mitosis does not.
Meiosis I
- Prophase I involves homologous chromosomes pairing up to form tetrads.
- Crossing over occurs in prophase I, where homologous chromosomes exchange genetic material.
- Metaphase I is when homologous pairs line up at the equator through independent assortment.
- Anaphase I involves homologous chromosomes separating and moving to opposite poles.
- Telophase I and cytokinesis result in two haploid cells, each with two chromatids per chromosome.
Meiosis II
- Prophase II involves chromosomes condensing again.
- DNA replication does not occur in prophase II.
- Metaphase II involves chromosomes lining up at the equator similar to mitosis.
- Anaphase II includes sister chromatids separating and moving to opposite poles.
- Telophase II and cytokinesis result in four haploid gametes that are genetically different.
Genetic Variation
- Crossing over during prophase I leads to new genetic combinations.
- Independent assortment during metaphase I leads to different gene combinations.
- Random fertilization results in unique sperm and egg combinations, totaling approximately 64 trillion genetic combinations.
Chromosomal Mutations
- Duplication: extra copies of genes.
- Deletion: loss of a section of a chromosome.
- Inversion: a segment of a chromosome is reversed.
- Translocation: a piece of one chromosome attaches to another.
Gametogenesis
- Spermatogenesis in males produces 4 functional sperm per meiosis.
- Oogenesis in females produces 1 egg and 3 polar bodies, with only the egg being functional.
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Description
Explore meiosis, the cell division process for creating gametes. Understand how meiosis differs from mitosis and the mechanisms that create genetic variation. Learn about chromosomes, including autosomes and sex chromosomes, and the significance of homologous chromosomes and gene loci.
