Biology for the Citizen review terms for Exam 2

allele

One of the different forms of a gene that can exist at a single locus on a chromosome, influencing traits in an organism.

genotype

The genetic constitution of an organism, represented by the alleles it possesses for a specific gene.

phenotype

The observable physical or biochemical characteristics of an organism, determined by its genotype and environmental factors.

Mendel’s laws

The principles of inheritance formulated by Gregor Mendel, including the Law of Segregation and the Law of Independent Assortment, which describe how traits are passed from parents to offspring.

Mendel’s law of segregation

The principle stating that during the formation of gametes, the two alleles for a trait separate, so that each gamete carries only one allele for each gene.

chromosomes

Structures within cells that contain DNA and carry genetic information essential for inheritance.

stem cells

Undifferentiated cells capable of giving rise to various cell types in the body, playing a crucial role in development and repair.

haploid cells

Cells that contain one complete set of chromosomes, half the number found in diploid cells, typically produced during meiosis.

gametes

Reproductive cells that unite during fertilization to form a new organism, containing half the genetic material of the organism. They include sperm and egg cells, essential for sexual reproduction.

locus

A specific, fixed position on a chromosome where a particular gene or genetic marker is located.

androgen allele

A variant form of a gene located at a specific locus on a chromosome that influences male traits and functions, often associated with the development of male characteristics.

G_0 phase

A phase in the cell cycle where cells are in a quiescent state, not actively dividing but metabolically active.

G_1 phase

The first phase of the cell cycle, following the G_0 phase, where the cell grows, synthesizes proteins, and prepares for DNA replication.

G_2 phase

The cell continues to grow and prepares for mitosis by synthesizing proteins and organelles.

interphase

The stage of the cell cycle that includes G_1, S, and G_2 phases, during which the cell grows and DNA is replicated in preparation for cell division.

prophase

The first stage of mitosis, during which chromatin condenses into visible chromosomes, the nuclear envelope begins to break down, and the mitotic spindle starts to form.

metaphase

The stage of mitosis where chromosomes align at the cell's equatorial plane, and spindle fibers attach to the centromeres.

anaphase

The stage of mitosis where sister chromatids are pulled apart toward opposite poles of the cell, ensuring each new cell will receive an identical set of chromosomes.

telophase

The final stage of mitosis, where chromosomes decondense back into chromatin, the nuclear envelope reforms around each set of chromosomes, and the cell begins to divide into two daughter cells.

chromatid

One of the two identical halves of a duplicated chromosome, joined at the centromere, that separates during cell division.

centriome

A structure in a cell that serves as the main microtubule organizing center, playing a crucial role in cell division by facilitating the separation of chromosomes.

centriole

A cylindrical structure found in animal cells, typically located near the centrosome, that helps organize microtubules during cell division.

homologous chromosome

Chromosomes that are similar in shape, size, and genetic content, one inherited from each parent, pairing during meiosis.

independent assortment

The principle that alleles of different genes segregate independently of one another.

crossing over

The exchange of genetic material between homologous chromosomes in meiosis.

random separation

the result of genetic variation

translation

the process in living cells in which proteins are produced using RNA molecules as templates. The generated protein is a sequence of amino acids.

transcription

the process of copying a segment of DNA into RNA for the purpose of gene expression.