Fertilization - joining of
male and female
reproductive cells during
sexual reproduction
True-breeding - offspring of
self-pollinated plants produce
offspring identical to itself
Cross-pollinate
Hybrid - the offspring of a
cross between parents
with different traits
Pea flowers normally self
pollinate - sperm cells in pollen
fertilize egg cells within the
pistil of the same flower
Traits
Dominant - expressed
by TT or Tt
Recessive - expressed when the
dominant allele is not present( tt )
Given that recessive traits
re-appear in the F2 generation,
alleles must have segregated
when gametes were formed
Terms
Probability - the likely-hood that
a particular event will occur
Can be used to predict the
outcome of genetic codes
Homozygous - 2
identical alleles
Heterozygous -
2 different alleles
Phenotype - physical
characteristics
Genotype -
genetic makeup
Principle of Independent Assortment: genes for
different traits can segregate independently
during gamete formation. This accounts for
many genetic variations in organisms
Codominance - both phenotypes are produced
Multiple Alleles - a gene with more than
2 possible alleles in a population
Polygenic traits - traits
controlled by 2 or more genes
Western White Butterfly
When adults hatch in spring, wings are darker than
those that hatch in summer. The dark wing color
helps increase their body heat in the cooler spring.
Diploid(2N) - a cell contains both
sets of homologous chromosomes
Haploid(N) - contains a
single set of genes;
Gametes(sex cells) are
haploid
Homologous Chromosomes - a pair
of chromosomes that carry genes
coding for the same characteristics
Tetrad - a pair of
homologous chromosomes;
includes 4 chromatids
Crossing Over - alleles are exchanged
between homologous chromosomes when
they are lined up as tetrads; produces a
new combination of alleles; contributes to
genetic diversity
Meiosis
Process when gametes are formed;
homologous chromosomes are
separated to create haploid gamates;
1 diploid = 4 haploid
Can't assort independently, they are linked
together because they are on the same gene. So,
their alleles tend to be inherited together. Crossing
over can be done and separate linked genes. The
loser together genes are on a chromosome the
more likely they will be inherited together.