Chapter 8: Hereditary

Mitochondria

Organelles responsible for converting energy from organic molecules into useful energy for the cell, with ATP being the most common energy molecule.

Cell Cycle Checkpoints

Control mechanisms that ensure proper cell division in eukaryotic cells, activated when damaged DNA is found, and regulate cell cycle progression through cyclin-dependent kinases (CDKs) and cyclins.

P Generation

The first generation in a genetics experiment, also known as the parent generation.

F1 Generation

The offspring of the P generation, also known as the first filial generation.

F2 Generation

The grandchildren generation in a genetics experiment.

Law of Dominance

A genetics principle discovered by Mendel, stating that when two true-breeding plants with contrasting traits are crossed, the offspring will have the dominant trait.

Law of Segregation

A genetics principle discovered by Mendel, stating that in a monohybrid cross, two alleles for a gene will segregate during gamete formation and end up in different gametes.

Punnett Squares

A tool used to predict the results of a genetics cross, particularly in monohybrid crosses, by showing all possible combinations of alleles from the parents.

Law of Independent Assortment

The law that states how one trait gets split up into gametes has no bearing on how the other trait gets split up.

Dihybrid Cross

A genetic cross that studies how two genes are passed on to offspring.

Rules of Probability

A method for predicting the likelihood of certain results from a dihybrid cross using the Product Rule and Sum Rule.

Product Rule

A rule that states the probability of two independent events occurring simultaneously is the product of the probability of each event occurring independently.

Sum Rule

A rule that states the probability of either event occurring, but not both, is the sum of the probabilities of each event.

Barr Bodies

Dark-staining body found in the cell nucleus of normal females.

Incomplete Dominance (Blending Inheritance)

A type of inheritance in which the traits of the offspring are a blend of the traits of the parents. Neither allele is dominant over the other.

Codominance

A type of inheritance in which both alleles are equally expressed, resulting in a phenotype that shows both traits.

Polygenic Inheritance

A type of inheritance in which a trait is determined by the interaction of multiple genes, each contributing a small effect to the trait.

Non-nuclear Inheritance

A type of inheritance in which genetic material is present in the mitochondria, which are always inherited through the maternal line in animals and plants.

Genotype

The genetic makeup of an organism, including all of its genes.

Phenotypic Plasticity

The ability of an organism with a particular genotype to produce different phenotypes in response to different environmental conditions.

Meiosis

The process of cell division that produces gametes (sex cells) in which the number of chromosomes is reduced by half.

Selective Advantage

A genetic advantage that improves an organism's chances of survival and reproduction in a particular environment, leading to the passing on of advantageous traits to future generations.

Meiosis

A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell.

Meiosis I

The first round of cell division in meiosis, which results in two daughter cells with half the number of chromosomes of the parent cell.

Prophase I

The first stage of meiosis I, where chromosomes become visible and form tetrads through synapsis, followed by crossing-over.

Synapsis

The pairing of homologous chromosomes during prophase I of meiosis, resulting in the formation of a tetrad.

Crossing-over

The exchange of genetic material between homologous chromosomes during meiosis, resulting in genetic variation.

Nondisjunction

A meiotic error where chromosomes do not separate properly, leading to an abnormal number of chromosomes in the resulting cells.

Down syndrome

A genetic disorder caused by the presence of three copies of the 21st chromosome, resulting in intellectual disability and physical abnormalities.