studying inheritance Flashcards
genotype
the genetic constitution of an organism, it describes all the alleles that an organism contains
mutation
change in the base sequence of DNA which causes a change in genotype
phenotype
the observable characteristics of an organism, it the result of the interaction between the expression of the genotype and environment
what is a modification
any change to the phenotype that does not affect the genotype and is not inherited
gene
a section of DNA consisting of a sequence of nucleotide bases - it usually determines a single characteristic of an organism
how does a gene determine a characteristic of an organism
- gene consists of a specific sequence of nucleotide bases (amino acids) - so it is the primary structure
- this codes for a particular polypeptide which makes the enzyme(s) needed in the biochemical pathway
- this leads to the production of the characteristic
alleles
different forms of a particular gene (e.g. eye colour)
so all individuals of the same species have the same genes, but not necessarily the same alleles of said genes
locus
position of a gene on a chromosome
diploid cell
has homologous chromosomes meaning there are two loci that can each carry one allele of a gene
homologous chromosomes
pair of chromosomes - one paternal and one maternal - that have the same gene loci
homozygous
both of the same alleles present in a homologous chromosomes pair loci
heterozygous
two different alleles present in the homologous chromosomes pair loci
- however only one of them will present itself in the phenotype
dominant allele
the allele of the heterozygote that expresses itself in the phenotype
recessive allele
the allele of the heterozygote that does not express itself in the phenotype
