Meiosis, Genetic Diversity, and Chloroplast Anatomy

A set of vocabulary flashcards reviewing cell division via meiosis, source mechanisms of genetic variation, chloroplast structural components, and organism lifecycles based on lecture materials.

Diploid cells ($2n$)

Cells that contain a pair of each chromosome ($2n$), such as human somatic cells which contain 23 pairs of chromosomes.

Haploid cells ($n$)

Cells that contain only one copy of each chromosome ($n$), such as gametes.

First division of meiosis

The stage in meiosis during which homologous chromosomes separate, halving the total number of chromosomes.

Second division of meiosis

The stage in meiosis during which chromatids separate, producing 4 haploid daughter cells.

Independent segregation

The random arrangement and separation of maternal and paternal homologous chromosome pairs during metaphase I of meiosis, yielding different chromosome combinations in gametes represented by the formula $2^n$, where $n$ is the number of homologous pairs.

Crossing over

A random event in Prophase I of meiosis where homologous chromosomes line up next to each other, chiasmata form, and equal lengths of chromosomes are exchanged to create new allele combinations.

Chiasmata

Structures formed during crossing over between homologous chromosomes aligned in synapsis, where exchange of chromosome lengths occurs.

Recombinant chromatids

Chromatids that display new allele combinations as a result of equal chromosome segment exchange during crossing over.

Synapsis

The state during Prophase I of meiosis wherein homologous chromosomes align side-by-side.

Alternate lifecycle

A life cycle in some species featuring distinct haploid ($n$) and diploid ($2n$) stages that involve mating types, nuclear fusion, zygospore formation, meiosis, spores, and hyphae mitosis.