monohybrid inheritance Flashcards
what is monohybrid inheritance?
inheritance of a characteristic controlled by a single gene
what happens if pea plants with green pods are bred repeatedly with each other so they give rise to plants with green pods?
they are pure breeding for the character of green pods. This means that the organisms are homozygous (two alleles the same) for that particular gene
what happens if pure breeding green pod plants are crossed with pure breeding yellow pod plants
the offspring (first filial/ F1 generation) produce green pods. so the allele for green pods is dominant to the allele for yellow pods which is recessive. All are heterozygous Gg (G= allele green pods g= allele yellow pods)
if the heterozygous plants of the F1 gen are crossed with one another what would occur in offspring (F2 gen)
the second filial generation are always in an approximate ratio of 3 plants with green pods to each one plant with yellow pods
what is the basic law of genetics (the law of segregation)
in diploid organisms characteristics are determined by alleles that occur in pairs. only one of each pair of alleles can be present in a single gamete
how does the ratio 3:1 relate to the number of offspring
the larger the number of offspring the more likely that the ratio will be 3:1. if the sample is very small this ratio is much less likely
what is a ratio?
the relative size of two classes that is expressed as a proportion
why are the actual results of genetic crosses rarely the same as predicted results?
due to statistical error. like flipping a coin 20 times you would expect 10 heads and 10 tails. however not the case because each toss of the coin is an independent event not affected by what went before. same with gametes. chance determines which ones fuse with the which
