Mendel Flashcards
before mendel, what did people believe in for heredity?
blending hypothesis - how blue and yellow make green
what did mendel introduce?
particulate hypothesis - discrete units called genes passed on from parents to offspring retain their separate identity
analogous to marbles in a bucket being passed into offspring
what did gregor mendel do as a profession?
monk
what did mendel work with?
pea plants
nickname of mendel?
Father of Genetics
what is an angiosperm?
flowering plants
parts of an angiosperm? (8)
petal
sepal - encase flower
filament - holds the pollen sack
anther - pollen sack
ovary
style - neck of ovary
stigma - sticky part of flower
stem
eggs of flowers
ovules
male parts of angiosperm
stamen - filament and anther
female parts of angiosperm
pistil/carpal - style and ovary
what is the mating of 2 varieties called?
hybridization
the mating of one character? two characters?
monohybrid; dihybrid
what did mendel’s experiment prove incorrect?
the blending model of inheritance was inccorect
what did the purple x white flowers in the p generation produce?
all purple flowers, not pale
therefore, purple flower color is dominant to white
how many characters did mendel observe the pattern of inheritance?
6 other - 7 total
what is the ratio of inheritance of mendel’s experiment?
3:1
how did mendel explain the ratio inheritance? (4)
1) alternate versions of genes account for variation (alleles)
2) organism inherits 2 alleles (mom and dad), and thus a genetic locus is represented twice in diploid organism- either heterozygous or homozygous
3) if alleles differ, dominant allele is expressed in phenotype, while recessive is not seen
4) Law of Segregation
Law of Segregation
the 2 alleles present in a cell segregate during meiosis, accounting for the haploid number in sperm and eggs
identical alleles
homozygous
alleles differ
heterozygous
how an organism looks
phenotype
genetic makeup
genotype
can we tell the genotype of a purple flower?
no it can be PP or Pp
what is test cross?
when you cross a mysterious organism with a homozygous recessive one to determine genotype
if all offspring have purple in a test cross what is the genotype?
PP
if half are purple and other half white after a test cross, what is the genotype?
Pp
how did Mendel discover his 2nd law?
performing dihybrid
he questioned whether 2 characters were inherited as a package or separately
what is mendel 2nd law?
Law of Independent Assortment
in a dihybrid, the two alleles for one character assort independently of the two alleles of another character
Law of Independent Assortment
traits separate and produce 4 gametes
4 gametes of RrYy
RY, Ry, rY, ry
genotype of RrYy x RrYy
1:2:1:2:4:2:1:2:1
phenotype of RrYy x RrYy
9:3:3:1
Law of Large Numbers
probability is closer to predicted results when sample size is increased
what does dominant really mean?
- not mean trait is more common (Polydactyly is dominant)
- it doesn’t mean the allele subdues a recessive allele
- it just is a working gene that makes a normal/functional protein
how does roundness come about in a pea rather than wrinkles?
due to the Prescence of an enzyme that converts simple sugars to starch
round peas have starch, wrinkled don’t
wrinkles store simple sugars rather than starch, so with osmosis water enters causing to to swell, and wrinkle when it dries