Meiosis Chapter 7 Flashcards

Homologous Chromosomes

• Homologous chromosomes consist of pairs of chromosomes: one inherited from the mother and one from the father.
• They are similar in length, gene position, and centromere location but may have different alleles.
• Each carries the same genes but not necessarily the same versions (alleles), leading to variation in traits like hair color.
• Sister chromatids are identical copies of a chromosome, while homologous chromosomes come from different parents and may differ in their genetic makeup.

Meiotic Division

• Meiosis consists of two cell divisions: Meiosis I and Meiosis II.
• During Meiosis I, chromosomes recombine, resulting in genetically diverse gametes; Meiosis II produces four haploid cells.
• The chromosome number is halved during Meiosis I, resulting in cells with half the original chromosome count.

Stages of Meiosis

• The stages of meiosis are:
  • Prophase I
  • Metaphase I
  • Anaphase I
  • Telophase I
  • Prophase II
  • Metaphase II
  • Anaphase II
  • Telophase II

Synapsis

• Synapsis occurs during Prophase I, where homologous chromosomes pair up in a highly specific alignment.

Crossing Over

• Crossing over happens in Prophase I when sister chromatids exchange segments of genetic material.
• This gene swapping introduces genetic diversity and can lead to new phenotypes after fertilization.

Gametogenesis: Spermatogenesis vs. Oogenesis

• Both processes involve meiosis but produce different outcomes.
• Spermatogenesis results in four sperm cells, while oogenesis produces one ovum and three polar bodies.
• Spermatogenesis occurs in the testes and has a shorter growth phase, while oogenesis occurs in the ovaries and has a longer growth phase.

Key Differences in Gametogenesis

• Spermatogenesis forms sperm; oogenesis forms ova.
• Polar bodies are formed during oogenesis but not during spermatogenesis.
• A single germ cell can produce 16 sperm, in contrast to the four ova produced from one germ cell in oogenesis.

Characteristics of Homologous Chromosomes

• Cells contain two of each chromosome type, with one from each parent.
• Paternal and maternal chromosomes may carry different alleles, contributing to genetic variation.

Cross-linking in Crossing Over

• During crossing over, homologous chromosomes become tightly aligned, allowing for the exchange of segments between non-sister chromatids.

Test your understanding of meiosis with these flashcards. This quiz focuses on homologous chromosomes, their similarities, and differences. Perfect for reviewing key concepts from Chapter 7 of your biology class.