BIO 171 EXAM 4 FULLY SOLVED EXAM PAPER
GRADED A+
◉ A researcher is creating pedigrees for a trait he suspects to be
dominant in humans. What are some of the likely features of his
pedigrees for families with this trait?
Answer: not:
-only females will have this dominant trait
-All the offspring of a mating where only one parent has the trait will
themselves be affected.
-The occurrence of mating between individuals with this trait will be
high, because all dominant traits are common within any given
population.
◉ You are given two true-breeding groups of rabbits. The first group
has floppy ears and white coat color. The second group has straight
ears and black coat color. When you perform a cross of these two
groups to obtain an F1 generation, you see that all of your rabbits
have floppy ears and grey coat color. Which of the following
possibilities appears to be supported by what you see in the F1
generation?
Answer: floppy ears are dominant over straight ears; coat color is
determined by incomplete dominance
,◉ genes that modify the expression of other genes show
Answer: epistasis
◉ With independent assortment, the ratio of phenotypes in the F2
generation of a cross between true-breeding strains (AA bb × aa BB)
can be described as 9:3:3:1 when A and B are dominant over a and b.
To what phenotype does the "9" in the ratio refer?
Answer: dominant for both traits
◉ a test cross of an organism of unknown genotype is done when
the organism is crossed to an organism that is
Answer: a recessive homozygote
◉ Why was it important for Mendel to remove the anthers from pea
plants in his experiments when crossing two different true-breeding
pea plants?
Answer: to prevent self fertilization
◉ One type of BRCA1 mutation is TAC TAC to TAA CTA C. This
sequence is from the non-template strand of DNA. Consider a person
who has this mutation and their biological mother. What is accurate
about this mutation?
Answer: the person's mother can pass this mutation to them, even if
the mother does not have the mutation in her somatic cells
, ◉ Jackson has type A blood while Phoebe has type O blood. Jackson
and Phoebe are full siblings. Which of the following is NOT a
possible genotype of one of their parents?
Answer: I_A,I_A
◉ A dog named Watson has very wrinkly skin. Everyone admired
Watson's wrinkly skin and so his owners decided to breed Watson
with another very wrinkly dog (named Crick). However, 2 of the
pups in the 8-puppy litter ended up with smooth skin. Given this,
what can we say about the genotypes of Watson and Crick?
Answer: Watson and Crick are both heterozygous for the wrinkly
skin
◉ If you crossed a true-breeding yellow seed plant (AA) with
heterozygous yellow seed plant (Aa):
Answer: offspring genotypes would be 1 AA : 1 Aa
◉ what is an allele?
Answer: a different form of a gene
◉ A true breeding black rabbit is crossed with a true breeding white
rabbit. If the black color trait is dominant, which of the following
represents the expected phenotype of an F2 generation consisting of
GRADED A+
◉ A researcher is creating pedigrees for a trait he suspects to be
dominant in humans. What are some of the likely features of his
pedigrees for families with this trait?
Answer: not:
-only females will have this dominant trait
-All the offspring of a mating where only one parent has the trait will
themselves be affected.
-The occurrence of mating between individuals with this trait will be
high, because all dominant traits are common within any given
population.
◉ You are given two true-breeding groups of rabbits. The first group
has floppy ears and white coat color. The second group has straight
ears and black coat color. When you perform a cross of these two
groups to obtain an F1 generation, you see that all of your rabbits
have floppy ears and grey coat color. Which of the following
possibilities appears to be supported by what you see in the F1
generation?
Answer: floppy ears are dominant over straight ears; coat color is
determined by incomplete dominance
,◉ genes that modify the expression of other genes show
Answer: epistasis
◉ With independent assortment, the ratio of phenotypes in the F2
generation of a cross between true-breeding strains (AA bb × aa BB)
can be described as 9:3:3:1 when A and B are dominant over a and b.
To what phenotype does the "9" in the ratio refer?
Answer: dominant for both traits
◉ a test cross of an organism of unknown genotype is done when
the organism is crossed to an organism that is
Answer: a recessive homozygote
◉ Why was it important for Mendel to remove the anthers from pea
plants in his experiments when crossing two different true-breeding
pea plants?
Answer: to prevent self fertilization
◉ One type of BRCA1 mutation is TAC TAC to TAA CTA C. This
sequence is from the non-template strand of DNA. Consider a person
who has this mutation and their biological mother. What is accurate
about this mutation?
Answer: the person's mother can pass this mutation to them, even if
the mother does not have the mutation in her somatic cells
, ◉ Jackson has type A blood while Phoebe has type O blood. Jackson
and Phoebe are full siblings. Which of the following is NOT a
possible genotype of one of their parents?
Answer: I_A,I_A
◉ A dog named Watson has very wrinkly skin. Everyone admired
Watson's wrinkly skin and so his owners decided to breed Watson
with another very wrinkly dog (named Crick). However, 2 of the
pups in the 8-puppy litter ended up with smooth skin. Given this,
what can we say about the genotypes of Watson and Crick?
Answer: Watson and Crick are both heterozygous for the wrinkly
skin
◉ If you crossed a true-breeding yellow seed plant (AA) with
heterozygous yellow seed plant (Aa):
Answer: offspring genotypes would be 1 AA : 1 Aa
◉ what is an allele?
Answer: a different form of a gene
◉ A true breeding black rabbit is crossed with a true breeding white
rabbit. If the black color trait is dominant, which of the following
represents the expected phenotype of an F2 generation consisting of
