Biology Chapter 8: Meiosis and Sexual Reproduction

A set of flashcards focusing on key vocabulary related to meiosis and cellular reproduction, designed to aid in understanding and recalling essential concepts.

Meiosis

A type of cell division that reduces the chromosome number by half, forming four haploid cells.

Diploid

A cell containing two complete sets of chromosomes, one from each parent (2n), e.g., 46 chromosomes in humans.

Haploid

A cell with a single set of unpaired chromosomes (n), e.g., 23 chromosomes in gametes.

Homologous chromosomes

Pairs of chromosomes containing the same genes but possibly different alleles, one inherited from each parent.

Crossing over

The exchange of genetic material between homologous chromosomes during Prophase I of meiosis, leading to genetic variation.

Independent orientation

The random arrangement of homologous chromosomes at the metaphase plate during meiosis I, contributing to genetic diversity.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during cell division, leading to an abnormal number of chromosomes in gametes.

Karyotype

A visual representation of an individual's chromosomes, arranged in pairs by size and shape, used to detect chromosomal abnormalities.

Trisomy 21

A genetic condition caused by the presence of an extra chromosome 21, commonly known as Down syndrome.

Polyploid

Organisms having more than two complete sets of chromosomes; common in plants.

Deletion

A chromosomal mutation where a fragment of the chromosome is lost.

Duplication

A chromosomal mutation that involves the duplication of a segment of the chromosome.

Inversion

A chromosomal alteration in which a fragment of a chromosome is reversed end to end.

Translocation

A chromosomal mutation that occurs when a segment from one chromosome is transferred to a non-homologous chromosome.

Sister chromatids

Identical copies of a chromosome connected by a centromere, formed after DNA replication.

Tetrad

A group of four chromatids formed during Prophase I of meiosis, consisting of two homologous chromosomes.

Gametes

Reproductive cells (sperm and egg) that are haploid, containing one set of chromosomes.

Zygote

The fertilized egg formed by the union of a sperm cell and an egg cell, which is diploid.

Sex chromosomes

Chromosomes that determine an individual's sex, represented as X and Y.

Autosomes

Non-sex chromosomes, of which humans have 22 pairs.