Chapter 14 Flashcards
what is the “blending” hypothesis?
the idea that genetic material from the two parents blends together and can never go back to what it was before
what is the “particulate” hypothesis?
the idea that parents pass on discrete heritable unites (genes)
-explains reappearance of traits after several generations
what did mendel discover?
the basic principles of heredity by breeding garden peas in carefully planned experiments
characters
distinct heritable features (such as flower color)
traits
character variants (such as purple or white)
true breeding
an organism that always passes down certain phenotypic traits (i.e. physically expressed traits) to its offspring
hybridization
two contrasting, true breeding varieties
P generation
the true breeding parents
F1 generation
hybrid offspring of the P generation
F2 generation
when F1 individuals self pollinate or cross pollinate with other F1 hybrids
what is the law of segregation?
stating that during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent.
-happens during anaphase 1 of meiosis 1
what is the ratio that mendel came up with for the offspring of the f1 generation
3:1
alternative versions of genes account for ______ in inherited characters
variations
alleles
alternative versions of a gene
each gene resides at a specific ____ on a specific chromosome
locus
for each character, an organism inherits ___ alleles
two (one from each parent)
if the two alleles at a locus differ, then the _____ allele determines the organism’s appearance, and the ______ allele has no noticeable effect on appearance.
- dominant
- recessive
homozygous
An organism with two identical alleles for a character
heterozygous
An organism that has two different alleles for a gene
true or false: heterozygous is true breeding
false
phenotype
physical appearance
genotype
genetic makeup
testcross
breeding the mystery individual with a homozygous recessive individual