Genetics

• Species: group of organisms that can interbreed and produce fertile offspring
• Heredity: the passing of traits, using genes, from one generation to the next
• Gene: section of DNA that codes for a protein
• Allele: alternative form of a gene
• Variation: differences between members of a species. 2 types: inherited and aquired
• Trait: a parental characteristic that can be genetically transmitted e.g. eye colour
• Chromosome: made of DNA and protein, found in nucleus of cell, visible at cell division
• Gene: section of DNA that codes for a specific protein and is responsible for a particular characteristic
• Genetics: study of biological inheritance and variation
• Gene expression: process of changing the information in a gene to make a protein by transcription and translation
• Locus: position of a gene on a chromosome
• Diploid (2n): a nucleus having 2 sets of chromosomes. Somatic cell
• Haploid (n): a nucleus having one set of chromosomes. Gamete cell
• Gamete: sex cell
• Fertilisation: fusion of 2 haploid gametes to form a single diploid cell called a zygote
• Homozygous: the same alleles for a characteristic
• Heterozygous: different alleles for a characteristic
• Genotype: the genetic makeup of an organism or genes present
• Phenotype: the physical expression of a gene in an organism. Depends on the genotype and environment
• Dominant: an allele that is always expressed
• Recessive: an allele whose expression is masked by a dominant allele. Only expressed when it is homozygous
• Incomplete dominance: neither allele masks the expression of the other allele
• Mendels first law- law of segregation: traits are controlled by pairs of factors which separate at gamete formation
• Mendels second law- law of independent assortment: either member of a pair of alleles can combine with either member of another pair
• Evolution: genetic changes in populations in response to environmental conditions
• Genetic engineering: artificial manipulation of a gene
• DNA profiling: using a persons DNA to create a unique pattern for analysis
• Sex linkage: gene located on the sex chromosome