Mitosis, Meiosis, and Mendelian Genetics

Flashcards covering key vocabulary terms related to mitosis, meiosis, and Mendelian genetics.

Mitosis

The process in which a cell divides to produce two identical daughter cells, involving the separation of sister chromatids.

Meiosis

A specialized type of cell division that reduces the chromosome number by half, producing four genetically diverse haploid cells for gametes.

Diploid (2n)

A cell or organism that has two sets of chromosomes, one from each parent.

Haploid (1n)

A cell or organism that has only one set of chromosomes, typically seen in gametes.

Homologous Chromosomes

A pair of chromosomes that contain the same genes, though not necessarily the same alleles.

Alleles

Different versions of a gene that can exist for a particular trait, can be dominant or recessive.

Genotype

The genetic makeup of an organism, represented by the combination of alleles.

Phenotype

The observable physical characteristics or traits of an organism resulting from its genotype.

Punnett Square

A grid used to predict the genetic makeup of offspring from a cross between two organisms.

Crossing Over

The process during meiosis where homologous chromosomes exchange genetic material, resulting in genetic variation.

Nondisjunction

An error in cell division where homologous chromosomes or sister chromatids fail to separate, which can lead to gametes with abnormal chromosome numbers.

Interphase

The phase of the cell cycle where the cell is not dividing, but is preparing for mitosis or meiosis by replicating its DNA.

Karyotyping

A laboratory technique used to visualize and analyze the number and structure of chromosomes in a cell.

Metaphase

A stage in mitosis and meiosis where chromosomes align along the metaphase plate, preparing for separation.

Anaphase

A stage in cell division where sister chromatids or homologous chromosomes are pulled apart to opposite poles.

Telophase

The final phase of cell division where the nuclear membrane reforms around each set of chromosomes, which de-condense back into chromatin.

Mitosis

The process of cell division in somatic cells that produces two genetically identical diploid daughter cells (2n), involving the separation of sister chromatids.

Meiosis

A specialized type of cell division in germline cells that produces four genetically diverse haploid cells (1n) (gametes) by reducing the chromosome number by half.

Somatic Cells

Any cell of the body except sperm and egg cells; these are diploid (2n). Examples include skin, muscle, and blood cells.

Germline Cells

Cells that produce gametes (sperm and egg cells); these undergo meiosis and are diploid (2n), producing haploid (1n) gametes.

Diploid (2n)

A cell or organism that has two sets of chromosomes, one from each parent; characteristic of human somatic cells.

Haploid (1n)

A cell or organism that has only one set of chromosomes; characteristic of human gametes (sperm and egg cells).

Homologous Chromosomes

A pair of chromosomes that contain the same genes, though not necessarily the same alleles.

Chromatin

A complex of DNA and proteins (histones) that forms chromosomes within the nucleus of eukaryotic cells. It de-condenses during interphase and condenses to form visible chromosomes during cell division.

Sister Chromatids

Two identical copies of a chromosome joined together by a centromere after DNA replication, before they are separated during cell division.

Centromere

The constricted region of a chromosome that links sister chromatids and serves as the attachment point for spindle fibers during cell division.

Interphase

The phase of the cell cycle where the cell grows, copies its DNA, and prepares for cell division, typically lasting the longest.

Spindle Fibers / Microtubules

Protein structures formed during cell division that extend from the centrosomes and attach to centromeres, playing a crucial role in separating chromosomes.

Centriole

A cylindrical organelle near the nucleus in animal cells, involved in the development of spindle fibers in cell division.

Metaphase

A stage in mitosis and meiosis where chromosomes align along the metaphase plate in the center of the cell, preparing for separation.

Anaphase

A stage in cell division where sister chromatids (in mitosis/meiosis II) or homologous chromosomes (in meiosis I) are pulled apart to opposite poles of the cell.

Telophase

The final phase of cell division where the nuclear membrane reforms around each set of chromosomes, which de-condense back into chromatin, and the cell prepares for cytokinesis.

Cytokinesis

The final stage of cell division, following mitosis or meiosis, during which the cell's cytoplasm divides to form two or four daughter cells. In animal cells, a cleavage furrow forms; in plant cells, a cell plate forms.

Crossing Over / Recombination

The process during prophase I of meiosis where homologous chromosomes exchange genetic material, resulting in genetic variation in gametes.

Nondisjunction

An error in cell division where homologous chromosomes or sister chromatids fail to separate, which can lead to gametes with abnormal chromosome numbers.

Meiosis I

The first division of meiosis, where homologous chromosomes separate, resulting in two haploid cells with duplicated chromatids.

Meiosis II

The second division of meiosis, where sister chromatids separate, resulting in four haploid cells, each with unduplicated chromosomes.

Alleles

Different versions of a gene that can exist for a particular trait, can be dominant or recessive.

Genotype

The genetic makeup of an organism, represented by the combination of alleles.

Phenotype

The observable physical characteristics or traits of an organism resulting from its genotype.

Punnett Square

A grid used to predict the genetic makeup of offspring from a cross between two organisms.

Homozygous

Having two identical alleles for a particular gene (e.g., AA or aa).

Heterozygous

Having two different alleles for a particular gene (e.g., Aa).