Cell Cycle and Meiosis Concepts

These flashcards focus on key terms and concepts related to cell cycle regulation and meiosis, which are essential for understanding the processes of cell division and genetic variation.

Negative regulation of the cell cycle

Involves proteins that act as brakes to slow down or stop cell division, ensuring proper conditions and correction of errors.

Proto-oncogene

A normal gene that promotes cell growth and division.

Oncogene

A mutated version of a proto-oncogene that can cause cancer by promoting uncontrolled cell proliferation.

Meiosis

A specialized type of cell division that reduces the chromosome number by half, creating four genetically distinct haploid cells.

Meiosis I

Reductional division where homologous chromosomes separate, resulting in two haploid cells.

Meiosis II

Equational division where sister chromatids separate, maintaining haploid chromosome number.

Crossing over

The exchange of genetic material between homologous chromosomes during prophase I, increasing genetic variation.

Synaptonemal complex

A protein structure that forms between homologous chromosomes during prophase I, facilitating synapsis and crossing over.

Chiasma

The point of contact between homologous chromosomes where crossing over occurred.

Hemizygous

A gene present in only one copy in a diploid organism, typically on a sex chromosome.

Homozygous

Having two identical alleles for a gene.

Heterozygous

Having two different alleles for a gene.

Homogametic

Refers to a sex with two identical sex chromosomes (XX in females).

Heterogametic

Refers to a sex with two different sex chromosomes (XY in males).

Diploid-dominant life cycle

A life cycle where the diploid stage is the longest and most visible part.

Haploid-dominant life cycle

A life cycle where the haploid stage is the longest and most visible part.

Alternation of generations

A life cycle pattern where an organism alternates between a multicellular haploid phase and a multicellular diploid phase.

Mitosis

A process that produces genetically identical somatic cells for growth and repair.

Meiosis

A process that produces genetically diverse gametes for sexual reproduction.

Number of divisions in mitosis

Involves one nuclear division.

Number of divisions in meiosis

Involves two nuclear divisions.

Daughter cells produced by mitosis

Results in two daughter cells.

Daughter cells produced by meiosis

Results in four daughter cells.

Genetic variation in mitosis

Produces genetically identical daughter cells.

Genetic variation in meiosis

Introduces genetic variation via crossing over and independent assortment.