Law of Segregation
Alleles separate such that each gamete has only one allele after Meiosis
Phenotype
Physical display of genes
Law of Independent Assortment
Inheritance of a gene is not dependent on another if the genes are on separate chromosomes.
Complete or Simple Dominance
When a recessive allele is masked by a dominate in the heterozygote
Incomplete Dominace
When heterozygotes have an intermediate phenotype between the two homozygotes
Codominance
When both alleles are equally expressed in the heterozygote
Epistasis
When one gene change the phenotype of another gene from a different chromosome
Polygenic Inheritance
When two or more genes work together to affect a trait
Recessive Genetic Disorders
Cystic Fibrosis, Tay Sachs Disease, Sickle Cell anemia
Dominant Genetic Disorders
Huntington's Disease, Achondroplasia
Sex-linked Genes
Genes carried on the "X" Chromosome
Human sex linked traits
Hemophilia, Colorblindness, Duschenna Muscular Dystrophy
Linked Genes
Genes carried on the same chromosome which are inherited together
Nondisjunction
When chromosomes don't separate during Anaphase I and Anaphase II
Barr Body
Structure that forms after one "X" chromosome is inactivated in a somatic cell
Gametes
Sex cells of an organism
Somatic Cells
Every cell other than the Gametes.
Locus
A gene's specific location along the length of a chromosome
Diploid Cell
Has two sets of chromosomal pairs (2n)
Haploid Cell
Has one set of chromosomes (n)
Zygote
Diploid cell that is an egg that is fertilized by sperm
Meiosis I
First step in which sexually reproducing organisms divide making half the number of chromosome sets as the original cell
Prophase I (Meiosis I)
Crossing over occurs, centrosome movement, spindle formation, nuclear envelope breakdown, Microtubules attach to the kinetochores
Metaphase I (Meiosis I)
Homologous pairs are arranged in the middle of the cell, Each pair has a kinetochore microtubule attached to it
Anaphase I (Meiosis I)
Breakdown of proteins between sister chromatids allowing the homologs to separate, homologs move towards opposite poles
Telophase I and Cytokinesis (Meiosis I)
Each half of the cell has a complete haploid set of chromosomes, cytokinesis
Meiosis II
Second step in which sexually reproducing organisms divide making half the number of chromosome sets from Meiosis I
Prophase II (Meiosis II)
Chromosomes once again move to the Metaphase plate
Metaphase II (Meiosis II)
Chromosomes are lined up at the Metaphase plate, microtubules extend from opposite poles
Anaphase II (Meiosis II)
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