Meiosis Chapter 7 Flashcards

Study Notes

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.

Description

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.