Genetics And Inheritence Flashcards
Define the term trait
A characteristic
Define the term gene
A section of dna that codes for a specific protein and determines a certain trait
Give the definition of an allele
An alternative form of a gene. Each individual organism has two alleles of each gene
Define the term genotype
The constitution of an organism
Define the term phenotype
The expression of the genetic constitution and its interaction with the environment
Define the term dominant allele
An allele that is always expressed if present in the genotype
Define the term recessive allele
An allele tjat is only expressed in the absence of the dominant allele
Define the term homozygous
Both alleles of a certain gene are identical
Define the term heterozygous
Both alleles of a certain gene are different
Define the term codominant
Both expressed in the phenotype of a heterozygote, so a third phentype arises
Give the definition of the term pure breeding
A group of identical individuals that always produce offspring of the same phenotype when intercrossed
Define the term locus
The position of a gene on a dna molecule
Describe the study of Mendel
He crossed a pure breeding tall plant with a pure breeding dwarf plant and produced all tall offspring
There was a 3:1 ratio. Between tall and dwarf plants
Describe sex linked genes
Genes that are carried on sex chromosomes are unrelated to sexual characteristics but are inherited in different ways
Describe epistaxis
When the allele of one gene affects or masks the expression of another in the phenotype
