17.1 Inheritance Flashcards
define gene
length of a DNA on a chromosome coding for one or more polypeptides
define allele
alternative forms of a gene
- there can be many, represented by a letter
define nucleotide
complex chemical (basic unit)
made up of:
- phosphate
- nitrogenous base
- pentose sugar
define genotype
genetic constitution of an organism
- describes all the alleles of an organism
define phenotype
observable or biochemical characteristics of an organism
- expressed genotype and its interaction with the environment
define dominant
allele that is always expressed in the phenotype
define recessive
allele that is expressed in the phenotype only when there is another identical one present
define codominant
when the two alleles contribute/are expressed in the phenotype
define locus (pl. loci)
position of a gene on a chromosome
define homozygote
organism carries 2 copies of the same gene
define heterozygote
organism carries different copies of the same gene
define carrier
individual carries an allele not expressed in the phenotype
- could be passed on to the offspring
define multiple alleles
gene that has more than two alleles