genetics & inheritance Flashcards
what sets mendel’s work apart from other researchers?
he used garden peas to study patterns of inheritance; took a quantitative approach to science in a time when qualitative was generally more accepted
what did mendel study?
he studied heritable characteristics he called characters (e.g. flower colour/seed shape). a variation in that character is called a trait.
Why the blending theory of inheritance was not plausible
blending theory believed that traits were a mix were a mix of both parents (phenotype). this did not explain outliers (e.g. a tall child from two short parents)
How Mendel employed the scientific method and components of his explanatory model
he employed the scientific method with careful experimentation with controlled crosses and quantitative analyses.
How different alleles differ from one another and how they can lead to different phenotypic characteristics
changes in sequence (location/nucleotide pairing) can change protein/how it functions leads to a different phenotypic characteristic
why transfusions are blood type-specific
type O is neither an antigen for A & B but it is an antibody for both - which is why it is considered a universal donor. type AB is an antigen for A & B but is an antibody for neither - which is why it is considered a universal recipient.
Why sex-linked characteristics follow different inheritance patterns than characteristics determined by genes on autosomal chromosomes
because females are always homozygous and males are heterozygous. there’s also no corresponding locus
Why sex-linked characteristics can have higher probabilities of appearing in offspring
traits are x-linked and males only need one affected allele to display traits
How polygenic traits lead to phenotypes that show continuous variation in a population
polygenic traits are determined by the influence of multiple alleles - many chromosomes are involved
What epistasis is and how it differs from Mendelian genetics
form of non-mendelian inheritance in which one gene is capable of interfering with expression of another (e.g. one gene determines color and the other determines if that colour is deposited)
why did mendel choose the garden pea?
he chose the garden pea because it can easily be grown without elaborate equipment
how did mendel perform the experiment?
he performed it using cross fertilization by brushing another plant’s sperm on another plant’s stigma. to prevent self fertilization he cut off anthers which produced pollen that contained sperm.
what did mendel conclude?
he established that characters passed to offsprings in forms of genes and that variation in traits were due to different alleles. alleles segregate randomly into gametes and that organisms inherit two alleles for each trait. the appearance of heterozygotes is determined by the dominant allele.
Distinguishing features of the different blood types
each blood type antigens are the same except for it terminal sugar which is transferred by the enzyme glycosyltransferase.
does the dominant allele inhibit the recessive allele?
products of recessive allele are generally weak or nonfunctional
