Exam 1 Flashcards
Cystic fibrosis can be inherited even if neither parent has the disease. This is because the disease
is caused by a recessive allele
If a homozygous dominant is crossed with a homozygous recessive for a given character, the offspring will be
all of the dominant phenotypes
In Mendel’s monohybrid cross of purple-flowered and white-flowered peas, all members of the F1 generation were of the
___ phenotype because their genotype
was ___
for the flower-color gene.
purple flowered, heterozygous
An AABb individual is mated with another AABb individual. The possible number of genetically distinct offspring is
3
A carrier of a genetic disorder who does not show symptoms is most likely to be ________
to transmit it to offspring.
heterozygous (carrier) for the disorder and able to pass it on
All the offspring of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is ___
to the allele for white flowers.
incompletely dominant
Traits that show a continuous distribution and a bell shaped curve are usually the result of
A polygenic trait
What is the prediction if colorblind man produces offspring with a heterozygous woman?
half of their sons and half of their daughters will be colorblind.
Genes located close together on the same chromosomes are referred to as ____ genes and generally ____
linked, do not sort independently during meiosis
We have a pea plant with purple flowers, determined by the dominant allele P. How might you determine whether the plant is homozygous (PP) or heterozygous (Pp).
Perform a testcross: Cross the plant with a white one, which must be homozygous recessive, or pp.
Flower color in snapdragons is an example of incomplete dominance. If a red-flowered plant is crossed with a white-flowered plant, the F1 generation has pink flowers.
If a pink-flowered plant is crossed with a pink-flowered plant, the progeny plants will be
25% red, 50% pink, and 25% white
Which of the following matings can NOT produce a child with blood type O? The letters refer to blood types (phenotypes).
O x AB
A woman with type O blood is expecting a child. Her husband is type A. Both the woman’s father and her husband’s father had type B blood. What is the probability that the child will have type O blood?
50%
The inheritance of height can best be described as?
Polygenic
Polygenic
Controlled by many genes, traits show gradual variation ie. varying heights, multiple genes and environmental factors effect a polygenic trait.
Complete Dominance is _____
One allele completely dominates the other
Incomplete Dominance-
The heterozygous phenotype is a blend of both alleles
Co-Dominance
The alleles share traits within offspring without blending.
What is the expected phenotype ratio of the offspring between double heterozygous individuals?
9:3:3:1
Dihybrid cross phenotypic ratio
If a fly is hererozygous for 2 genes, how many unique gametes will they make?
2^n Law of Independent Assortment
N= number of heterozygous pairs
If a AaBbCc individual mates with a AaBbCc individulal what is the probability of an AABBCC offspring?
1/64
What is the phenotype of a fly that is homozygous dominant for body color and heterozygous for wing size?
Wild type body and wings
Wild type
Most common allele in a population
If a gene has a homozygous dominate lethal genotype, the genotype ratio of the offspring would be:
2:1 excluding the AA which does not survive
