The Cell Cycle, Meiosis, and Genetics Review

Vocabulary practice flashcards covering cell cycle phases, mitosis, meiosis, chromosome structure, Mendelian inheritance, and non-Mendelian genetics.

Genome

An organism's complete set of genetic instructions made of DNA.

Chromatin

A complex of DNA and protein that condenses during cell division in eukaryotic cells.

Somatic cell

Any biological body cell other than a gamete (such as skin, liver, or bone cells) containing $46$ chromosomes ($23$ pairs) and $46$ DNA molecules in humans.

Gamete

A reproductive cell (specifically sperm or egg) that passes genes to the next generation and contains $23$ chromosomes in humans.

Centromere

A region of DNA and part of the chromosome where one sister chromatid attaches to the other sister chromatid.

Mitosis

A type of division that conserves the number of chromosome sets, producing cells that are genetically identical to the parent cell.

Meiosis

A type of division that reduces the number of chromosome sets from two (diploid) to one (haploid), producing cells that differ genetically from each other and from the parent cell.

Cell cycle

A series of events in which a cell grows, copies its DNA, and divides into two daughter cells.

Mitotic spindle

A cellular structure consisting of microtubules (spindle fibers) and proteins, which begins assembling at the centrosome in animal cells.

Tubulin

A protein already present in the cell's cytoplasm used to assemble the microtubules of the mitotic spindle.

Centrosome

The region in animal cells where the assembly of spindle microtubules starts during cell division.

Binary fission

The asexual process by which prokaryotes reproduce, which does not involve mitosis.

Gene

A discrete hereditary unit consisting of a specific DNA sequence that transmits inherited information to the next generation.

Locus

The specific physical location of a gene along the length of a chromosome.

Karyotype

An ordered display and preparation of an individual's complete set of chromosomes arranged to determine chromosomal characteristics.

Homologous chromosomes

A pair of chromosomes that share the same size, centromere position, and carry genes controlling the same inherited characters, with one derived from each parent.

Sex chromosomes

Chromosomes that determine the sex of an organism, represented in humans by the X and Y chromosomes.

Autosomes

All chromosomes in an organism that are not directly involved in determining sex.

Independent assortment

A mechanism that increases genetic diversity during meiosis through the random distribution and orientation of maternal and paternal chromosomes.

Crossing over

The exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis that creates recombinant chromosomes.

Random fertilization

A mechanism contributing to genetic variation in sexually reproducing organisms based on the random chance of any single sperm fertilizing any single ovum.

Genotype

The underlying genetic makeup or combination of alleles for an organism (such as $Rr$ or $bbSs$).

Phenotype

The observable physical or physiological traits expressed by an organism (such as red flower color or curly coat).

Incomplete dominance

A pattern of inheritance where neither allele is completely dominant, resulting in a heterozygous phenotype that is intermediate between the two homozygotes.

Codominance

A pattern of inheritance where the effect on the phenotype of each allele is equal, so that both phenotypes are simultaneously observed in a heterozygote.

Roan

A coat color phenotype in short horn cattle displaying red and white patches equally due to codominance of the red ($R$) and white ($W$) alleles ($RW$).

Sex-linked traits

Traits controlled by genes located on sex chromosomes, most commonly the X chromosome which carries approximately $1200$ genes compared to about $80$ genes on the Y chromosome.

Muscular dystrophy

A fatal sex-linked recessive disease that causes progressive muscle weakness and degeneration.

Carrier

A heterozygous individual who carries a recessive allele for a disorder (such as $X^D X^d$ or $X^N X^n$) without displaying phenotypic symptoms, capable of passing the allele to offspring.