Genetics and Heredity Overview

The branch of science that examines heredity (characteristics passed from parents to offspring) and the variations seen in those inherited characteristics. It explores how traits are transmitted and how differences between individuals arise.

The differences observed between individuals within a species or a population. These differences can encompass various physical, physiological, and behavioral characteristics.

The process of passing on features, characteristics, or traits from one generation to the next. This transmission ensures the continuity of a species while also contributing to the variations observed within it.

Thread-like structures found within the nucleus of a cell. They contain the genetic information (DNA) that determines an organism's traits. Each cell has a fixed number of chromosomes.

Pairs of chromosomes that determine an organism's sex. In humans, females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

All the chromosomes except for the sex chromosomes. They carry genes that determine various traits, such as hair color, eye color, and height. Humans have 22 pairs of autosomes.

Segments of DNA located along the chromosome. They contain the specific instructions that determine a particular trait. Each gene occupies a specific location on a chromosome.

Deoxyribonucleic acid - a complex molecule that forms the basis of genes. It contains the coded instructions that dictate an organism's characteristics. DNA is arranged within chromosomes.

The period between mitotic divisions (G1, S, and G2) where the cell grows and prepares for division.

The stage of the cell cycle where the cell's genetic material (DNA) is duplicated.

The process of nuclear division where one cell divides into two identical daughter cells, each containing the same number of chromosomes.

The division of the cytoplasm following mitosis, resulting in two separate cells.

The first gap phase in the cell cycle, where the cell grows and prepares for DNA replication.

The second gap phase in the cell cycle, where the cell continues to grow and prepares for mitosis.

A checkpoint in the G1 phase where the cell commits to division.

Cell division that occurs in multicellular organisms for growth, repair, and replacement of worn-out cells.

The total number of chromosomes found in a typical human cell, organized in pairs.

Sex cells, like sperm and ova, contain only 23 chromosomes, half the number of chromosomes found in a normal body cell.

A long molecule that carries genetic information, providing instructions for building and maintaining an organism.

Unique segments of DNA located on chromosomes, responsible for determining specific traits or characteristics.

Alternative forms of a gene, influencing variations of a trait. For example, one allele for a gene might determine blue eyes, while another allele determines brown eyes.

The allele that dominates and expresses its trait, even if a recessive allele is present in the pair. For example, if one allele for eye color is brown and the other is blue, the brown allele will be dominant and result in brown eyes.

The allele that remains hidden when paired with a dominant allele. It does not affect the trait unless the dominant allele is absent.

The process by which cells divide to create new cells. It involves the division of the nucleus, followed by the division of the cytoplasm.

Specialized cells involved in sexual reproduction. They are haploid, containing only one set of chromosomes.

The number of chromosomes in a normal body cell. It's a complete set of chromosomes, consisting of two copies of each.

The number of chromosomes in a gamete. It's half the number of chromosomes found in a diploid cell.

Traits that are passed from parents to offspring through genes, influencing their physical characteristics and abilities.

The inheritance of genes for different traits is independent of each other. This means that the genes for eye color and hair color, for example, are inherited separately.

During gamete formation, each pair of alleles separates, with one allele going to each gamete. This ensures that each offspring receives one allele from each parent.

The trait that is expressed in the offspring when both dominant and recessive alleles are present. This trait masks the recessive allele.

The trait that is only expressed when two copies of the recessive allele are present. This trait is masked by the dominant allele if it is present.

The first generation of offspring produced by crossing two parents. This generation will display the dominant trait, even if the recessive allele is present.

The second generation of offspring produced by crossing individuals from the F1 generation.

The different forms of a gene. For example, the gene for eye color has different alleles: one for brown eyes and one for blue eyes.

An allele that masks the effect of another allele when both are present.

An allele whose effect is masked by a dominant allele.

The process of determining the sex of an offspring.

The inheritance pattern where the father's contribution determines the sex of the offspring. The mother always contributes an X chromosome, and the father can contribute either an X or a Y.