exam review

• cell cycle: interphase, mitosis, cytokinesis
• interphase: G1, S, G2
• G1 phase: growth phase where cell grows to double its size
• S phase: synthesis phase where DNA is replicated
• G2 phase: gap phase where the cell prepares for division
• mitosis steps: 1. DNA replicates 2. Chromosomes condense 3. Chromosomes separate 4. Cytokinesis
• meiosis: process that produces gametes (sex cells)
• cytokinesis: formation of two daughter cells from one parent cell
• prophase I: chromatin condenses into visible chromosomes; homologous pairs line up at metaphase plate
• metaphase I: homologous pairs align along equatorial plane
• anaphase I: homologous pairs move apart towards opposite poles
• telophase: the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.
• chromosome locations: nucleus, mitochondria, chloroplasts, cytoplasm
• DNA complimentary base pairs are A-T and G-C
• crosses expected ratios: monohybrid 3:1
• dihybrid: 9:3:3:1
• dominant trait masks recessive trait
• allele: each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
• allele: variant of a gene
• dominant gene: a gene that is expressed in the phenotype of an individual
• recessive gene: a gene that is expressed only when paired with a dominant allele
• codominant meaning both alleles are expressed in the phenotype, but the phenotype is different
• incomplete dominant: neither trait fully shows
• incomplete dominant: dominant allele is not expressed in the phenotype
• gene: (in informal use) a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring
• genotype: the genetic constitution of an individual organism.
• phenotype: the observable characteristics or traits of an individual resulting from the interaction of its genotype with the environment
• trait: a distinguishing quality or characteristic, typically one belonging to a person
• Mendel's experiments results: 1. F1 hybrids were always fertile 2. F1 hybrids were always heterozygous
• F1 generation: first filial generation; the hybrid offspring produced by crossing two pure-breeding parents that are homozygous recessive at a particular locus
• F2 generation: second filial generation; the progeny of any cross between individuals of different genotypes
• Punnett square: a table used to predict the probability of different phenotypes arising from a cross between individuals carrying different alleles
• mendels experiments: conclusions: 1. inheritance of traits is determined by a single gene 2. genes are located on a single chromosome
• mutations lead to genetic variation, which is the basis of evolution
• pedigree analysis is the study of the inheritance of traits in a family
• pedigree analysis carriers of a recessive allele are more likely to have children with the disorder
• x-linked recessive disorders are caused by a mutation on the X chromosome
• x-linked means that the gene is located on the X chromosome, and is only expressed in males
• carriers in genetics are the genes that are responsible for the expression of a trait
• coming up with genotypes is a process of elimination, where you start with a set of genotypes and eliminate them based on the phenotypes