6.1.2 pattern of inheritance

what does genotype mean?

the Alleles of a organism

what does phenotype mean?

the physical characteristics of a organism

what is a allele?

different version of the same gene

what does the dominant gene mean

gene that’s always expressed ( makes the protein )

what does the recessive gene mean?

only expressed when both genotypes are recessive

how are recessive genotype shown?

aa ( lower case letters)

how are Dominant genotypes shown?

AA ( upper case letters)

what does homozygous mean

2 identical alleles

what does heterozygous mean

2 different alleles

what are the types of genotypes

monogenic

polygenic

what factors affect phenotype

environmental and genotype

what does monogenic mean

1 gene controls characteristics

what does polygenic mean

multiple genes control characteristics

what are the two phenotypic variation in plants

chlorosis

Etiolation

what are the two phenotypic variation in plants caused by

the environment

Chlorosis meaning and what causes it ?

Plants don’t produce enough chlorophyll and turn yellow

Lack of Mg in the soil

Etiolation meaning and what causes it ?

plants grow abnormally long and spindly

due to a lack of sunlight

Codominant definition

both alleles are expressed in a phenotype

Carrier definition

A Organism carrying an allele which is not expressed in the phenotype

Monogenic Punnet square

How to complete a punnet square

1) show parents genotype

2) show the gametes

3) times the letter ( FOIL)

4) produce punnet square

what is the usual ratio for Dihybrid crosses between two heterozygous parents

9 : 3 : 3 : 1

how to work out offspring genotype in punnet square

allele x allele ( RY X rY) = RrYY

how to work out gametes in punnet square

FOIL ( first outer inner last)

Dihybrid punnet square image