Edexcel Biology B A-level Chapter 8 - Origins of
genetic variation Questions With Complete Solution
Homozygote
An individual where both the alleles coding for a particular characteristic are
identical.
Heterozygote
An individual where the two alleles coding for a particular characteristic are different.
Dominance
When a phenotype is expressed whether the individual is homozygous for a
characteristic or not.
Recessive
When a phenotype is only expressed when both alleles code for the recessive
feature, in other words the individual is homozygous recessive for a characteristic.
Polygenic
Phenotypic traits that are determined by several interacting genes.
Monogenic cross
A genetic cross where only one gene is considered.
Law of segregation
This describes Mendel's first law, which states that one unit or allele for each trait is
inherited from each parent to give a total of two alleles for each trait. the segregation
(separation) of alleles in each pair takes place when the gametes are formed and
some alleles code for phenotypes that are dominant over others.
Law of independent assortment
This describes Mendel's second law, which states that different traits are inherited
independently of each other. This means that the inheritance of alleles for one
phenotype has nothing to do with the inheritance for another characteristic.
Multiple alleles
There are more than two possible variants at a particular locus.
Codominant
When both alleles are expressed and the proteins they code for act together without
mixing to produce a given phenotype.
Parental phenotypes
genetic variation Questions With Complete Solution
Homozygote
An individual where both the alleles coding for a particular characteristic are
identical.
Heterozygote
An individual where the two alleles coding for a particular characteristic are different.
Dominance
When a phenotype is expressed whether the individual is homozygous for a
characteristic or not.
Recessive
When a phenotype is only expressed when both alleles code for the recessive
feature, in other words the individual is homozygous recessive for a characteristic.
Polygenic
Phenotypic traits that are determined by several interacting genes.
Monogenic cross
A genetic cross where only one gene is considered.
Law of segregation
This describes Mendel's first law, which states that one unit or allele for each trait is
inherited from each parent to give a total of two alleles for each trait. the segregation
(separation) of alleles in each pair takes place when the gametes are formed and
some alleles code for phenotypes that are dominant over others.
Law of independent assortment
This describes Mendel's second law, which states that different traits are inherited
independently of each other. This means that the inheritance of alleles for one
phenotype has nothing to do with the inheritance for another characteristic.
Multiple alleles
There are more than two possible variants at a particular locus.
Codominant
When both alleles are expressed and the proteins they code for act together without
mixing to produce a given phenotype.
Parental phenotypes
