Genes

• Allele


  Variant form of a gene, occupying a specific locus on a chromosome, influencing an organism's trait
• Cell Division


  Parent cell divides into two or more daughter cells, essential for growth and reproduction
• Centromere


  Region of a chromosome where sister chromatids are joined and spindle fibers attach during cell division
• Chromosome


  Thread-like structure carrying genetic information, composed of DNA and proteins, found in the cell nucleus
• Diploid


  Cells containing two sets of chromosomes, one from each parent, typical of somatic cells in humans (2n)
• DNA Replication


  Process of copying DNA molecules to produce identical copies, occurring before cell division
• Dominant


  Allele that masks the expression of another allele when present, determining the organism's phenotype
• Fertilization


  Union of gametes (sperm and egg) to form a zygote, restoring the diploid chromosome number in sexually reproducing organisms
• Genetic Cross


  Breeding experiment designed to study the inheritance of traits by mating organisms with different genotypes
• Genotype


  Genetic makeup of an organism, represented by the combination of alleles for a particular trait
• Haploid


  Cells containing one set of chromosomes, half the diploid number, found in gametes in humans (n)
• Homologous Chromosomes


  Chromosome pairs with similar genes but potentially different alleles, inherited from each parent, involved in meiosis
• Meiosis


  Cell division producing gametes with half the chromosome number, essential for sexual reproduction and genetic diversity
• Mendelian Genetics


  Study of inheritance patterns and the principles of heredity proposed by Gregor Mendel in the 19th century
• Mitosis


  Cell division resulting in two identical daughter cells, crucial for growth, repair, and asexual reproduction in eukaryotes
• Phenotype


  Observable characteristics of an organism, resulting from the interaction between genotype and environment
• Punnett Square


  Diagram used to predict the possible genotypes and phenotypes of offspring in a genetic cross
• Recessive


  Allele whose expression is masked by a dominant allele, only expressed when both alleles are recessive
• Sister Chromatids


  Identical DNA molecules resulting from DNA replication, attached at the centromere, separated during cell division
• Zygote


  Diploid cell formed by the fusion of gametes during fertilization, develops into a new organism
• One common chromosomal abnormality is Down syndrome, which is caused by an extra copy of chromosome 21.
• Another example of a chromosomal abnormality is Turner syndrome, where females are born with only one X chromosome instead of two.
• Chromosomal abnormalities can result from errors during cell division, leading to an atypical number of chromosomes in an organism.