Meiosis and Sexual Life Cycles

A comprehensive set of vocabulary flashcards covering the key concepts of meiosis and sexual life cycles.

Meiosis

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

Haploid

A cell that contains one complete set of chromosomes (n). For humans, this is 23 chromosomes.

Diploid

A cell that contains two complete sets of chromosomes, one from each parent (2n). For humans, this is 46 chromosomes.

Gametes

Reproductive cells (sperms and eggs) produced by meiosis.

Fertilization

The process of combining a sperm and egg to form a diploid zygote.

Chromosome

A structure made of DNA and proteins that carries genetic information.

Homologous chromosomes

A pair of chromosomes, one from each parent, that are similar in shape, size, and genetic content.

Sister chromatids

Identical copies of a single chromosome that are connected by a centromere.

Crossing over

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

Chiasmata

X-shaped regions where crossing over occurs between homologous chromosomes.

Centromere

The region of a chromosome where sister chromatids are joined together.

Karyotype

A profile of an individual's chromosomes, arranged and stained for study.

Prophase I

The first stage of meiosis I where homologous chromosomes pair and crossing over occurs.

Metaphase I

The stage of meiosis I where homologous chromosomes align at the metaphase plate.

Anaphase I

The stage of meiosis I where homologous chromosomes are pulled apart to opposite poles.

Telophase I

The stage of meiosis I where the cell divides into two haploid cells.

Cytokinesis

The process that divides the cytoplasm of a parent cell into two daughter cells.

Meiosis II

The second phase of meiosis, similar to mitosis, where sister chromatids are separated.

Prophase II

The stage of meiosis II where the spindle apparatus forms and chromosomes condense.

Metaphase II

The stage of meiosis II where sister chromatids align at the metaphase plate.

Anaphase II

The stage of meiosis II where sister chromatids are pulled apart to opposite poles.

Telophase II

The stage of meiosis II where nuclei form and cytokinesis separates the cells.

Independent assortment

The random orientation of homologous chromosome pairs during meiosis I.

Genetic variation

Diversity in gene frequencies that contributes to evolution.

Alleles

Different versions of a gene that arise from mutations.

Zygote

The fertilized egg that results from the union of sperm and egg.

Synapsis

The process where homologous chromosomes pair during prophase I.

Recombinant chromosomes

Chromosomes that have gone through crossing over and carry genes from both parents.

DNA

The molecule that carries the genetic instructions for life.

Spermatogenesis

The process of producing sperm in males through meiosis.

Oogenesis

The process of producing eggs in females through meiosis.

Interphase

The phase of the cell cycle where the cell prepares for division.

Fertilization and meiosis

Processes that alternate in the sexual life cycle to maintain chromosome number.

Cleavage furrow

A constriction in the cell membrane that occurs during cytokinesis in animal cells.

Cell plate

A structure that forms during cytokinesis in plant cells to separate daughter cells.

Evolutionary significance of genetic variation

The role genetic variation plays in natural selection and adaptation.

Mutations

Changes in DNA that create new alleles and contribute to genetic diversity.

Random fertilization

The concept that any sperm can fuse with any ovum, increasing genetic diversity.

Multicellular diploid adults

Organisms that grow from diploid zygotes and are made up of diploid cells.

Meiosis I

The first part of meiosis which separates homologous chromosomes.

Meiosis II

The second part of meiosis that separates sister chromatids.

Mitosis vs. Meiosis

Mitosis produces identical cells while meiosis produces genetic variation.

Progenitor cell

A cell that can give rise to more cells of the same type.

Sister chromatid cohesion

The process by which sister chromatids stick together until separation.

Paternal

Referring to the father's genetic contribution.

Maternal

Referring to the mother's genetic contribution.

Half the chromosomes

The result of meiosis, producing gametes with half the chromosomes of the parent cell.

Chromosome duplication

The process by which a chromosome makes a copy of itself before cell division.

Meiotic spindle

The structure that separates chromosomes during meiotic cell division.

Cohesins

Proteins that hold sister chromatids together.

Nonsister chromatids

Chromatids of homologous chromosomes that are not identical.

Metaphase plate

An imaginary plane that is equidistant from the two poles of a cell where chromosomes align.

Chiasma formation

The physical exchange of chromosome segments that occurs during prophase I.

Kinetochore

The protein structure on the centromere where spindle fibers attach.

Homologs

Chromosomes that are similar in shape and size, with genes for the same traits.

Duplicated chromosome

A chromosome consisting of two sister chromatids connected by a centromere.

Gene

A segment of DNA that codes for a protein or a trait.

Life cycle

The series of stages through which an organism passes from the start of its life until reproducing.

Fertilization and meiosis

Two key processes in the sexual life cycle that maintain genetic diversity.

Chromosomal variation

Diverse arrangements and combinations of chromosomes that arise through meiosis.

Crossover frequency

The average number of crossover events occurring during meiosis per chromosome.

Genetic recombination

The process by which genetic material is physically mixed during meiosis.

Genotype

The genetic makeup of an organism.

Phenotype

The observable traits or characteristics of an organism.

Proteins

Molecules composed of amino acids that perform various functions in living organisms.

Transmission genetics

The study of how traits are passed from one generation to the next.

Mendelian inheritance

The manner by which genes and traits are passed from parents to their offspring.

Biological diversity

The variety and variability of life forms within a given ecosystem.

Dominant trait

A genetic trait that is expressed in the phenotype over a recessive trait.

Recessive trait

A genetic trait that is masked by a dominant trait when both are present.

Polygenic inheritance

The form of inheritance in which multiple genes affect a single trait.

Chromosomal aberration

An irregularity in chromosome number or structure.

Aneuploidy

An abnormal number of chromosomes in a cell.

Polyploidy

A condition in which an organism has extra sets of chromosomes.

Allele frequency

The relative frequency of a particular allele in a population.

Genetic drift

Random changes in allele frequencies in a population from generation to generation.

Gene flow

The transfer of alleles from one population to another.

Natural selection

The process where organisms better adapted to their environment tend to survive and produce more offspring.

Speciation

The formation of new and distinct species in the course of evolution.

Adaptive radiation

An evolutionary pattern in which many species evolve from a single ancestral species.

Extinction

The end of an organism or a group of organisms, resulting in the loss of its gene pool.

Biological evolution

Change in the heritable characteristics of biological populations over successive generations.

Phenotypic plasticity

The ability of an organism to change its phenotype in response to changes in the environment.

Mutation rate

The frequency at which new mutations occur in a genome.

Homologous recombination

The exchange of genetic material between homologous chromosomes during meiosis.

Sexual selection

A form of natural selection where individuals with certain inherited characteristics are more likely than others to obtain mates.

Fossil record

The history of life as documented by fossils.

Biogeography

The study of the distribution of species and ecosystems across the planet.

Common ancestor

An ancestral species from which two or more species have evolved.

Phylogenetics

The study of evolutionary relationships among biological entities.

Speciation rates

The frequency at which new species arise in a given lineage.

Gene editing

The alteration of genes within an organism's genome.

Transgenic organisms

Organisms that have been genetically engineered to contain DNA from another species.

Conservation genetics

The study of genetic variation within and between populations of species, often for conservation efforts.

Functional genomics

The study of gene and protein functions and interactions.

Proteomics

The large-scale study of proteins, particularly their functions and structures.

Bioinformatics

The application of computational tools to manage and analyze biological data.

Gene therapy

The experimental technique that uses genes to treat or prevent disease.

Synthetic biology

The design and construction of new biological parts, devices, and systems.

Gene drive

A genetic engineering technology that propagates particular genes to increase their prevalence in a population.