Biology Exam 4 Pt. 2
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A woman of blood group A has a child with a man of blood group B. The child's blood is type O. What must be the genotype of the parents?
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Mother: I(A)I(A); father I(B)I(A)
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Mother: I(A)i(O); father: I(B)I(B)
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Mother: I(A)i(O); father I(B)i(O)
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Mother: I(A)i(O); father I(B)I(B)
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It is impossible for these individuals to have a chlld with type O blood.
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Biology Exam 4 pt. 2 assesses understanding of genetics, including blood type inheritance, co-dominance, Mendel's experiments, and genetic traits. It tests key concepts in genetics crucial for students in biology.
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- 2.
Cocominance
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Is when heterozygotes show a phenotype intermediate between those of the two homozygotes.
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Involves the expression of both alleles at a locus producing two different phenotypes.
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Is only found in mammalian enzyme production.
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Involves one allele having more than one phenotypic effect.
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Would result in pink flowers from a cross between white and red flowers.
Correct Answer
A. Involves the expression of both alleles at a locus producing two different phenotypes.Explanation
Cocominance is a genetic phenomenon where both alleles at a specific locus are expressed, resulting in the production of two different phenotypes in heterozygotes. This means that neither allele is dominant or recessive over the other, and both are fully expressed. It is not limited to mammalian enzyme production and can occur in various organisms. In the case of flower color, if cocominance is present, a cross between white and red flowers would result in offspring with pink flowers, as both the white and red alleles would be expressed simultaneously.Rate this question:
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- 3.
In Mendel's experiments, if the allele for tall (7) plants was incompletely dominant over the allele for short (t) plants, what offspring would have resulted from crossing two Tt plants?
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1/4 tall; 1/2 intermediate height; 1/4 short
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1/2 tall; 1/4 intermediate height; 1/4 short
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1/4 tall; 1/4 intermediate height; 1/2 short
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All tall offspring
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All intermediate height offspring
Correct Answer
A. 1/4 tall; 1/2 intermediate height; 1/4 shortExplanation
When the allele for tall plants is incompletely dominant over the allele for short plants, the offspring resulting from crossing two Tt plants would show a phenotype that is a blend of the two parental phenotypes. This is known as incomplete dominance. In this case, 1/4 of the offspring would be tall (TT), 1/2 would have an intermediate height (Tt), and 1/4 would be short (tt).Rate this question:
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- 4.
Classical albinism results from a recessive allele. Which of the following is the expected ratio for the progeny when a normally pigmented male with an albino father has children with an albino woman?
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3/4 normal; 1/4 albino
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3/4 albino; 1/4 normal
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1/2 normal; 1/2 albino
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All normal
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All albino
Correct Answer
A. 1/2 normal; 1/2 albinoExplanation
When a normally pigmented male with an albino father has children with an albino woman, the expected ratio for the progeny is 1/2 normal and 1/2 albino. This is because the albino father must carry the recessive allele for albinism, and when he passes it on to his son, the son becomes a carrier of the allele. When the carrier son then has children with an albino woman, there is a 50% chance that he will pass on the normal allele and a 50% chance that he will pass on the recessive allele, resulting in a 1/2 normal and 1/2 albino ratio for the progeny.Rate this question:
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- 5.
A human male carrying an allele for a trait on the X chromosome is
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Heterozygous.
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Homozygous.
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Hemizygous.
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Monozygous.
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Holozygous.
Correct Answer
A. Hemizygous.Explanation
A human male carries only one X chromosome and one Y chromosome, while a female carries two X chromosomes. Since the allele for the trait is located on the X chromosome, a male can only have one copy of that allele. Therefore, the term "hemizygous" is used to describe males in this context, as they have only one copy of the allele on the X chromosome.Rate this question:
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Mar 20, 2023Quiz Edited by
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May 11, 2010Quiz Created by
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