Bio 1010 - General Biology » Summer 2022 » Genetics Lab Quiz

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Question #1
A true-breeding red rose is repeatedly mated with a true-breeding white rose, and all of their offspring are red. If two of these red offspring are mated, what percentage of their offspring will be red?
A.   75%
B.   0%
C.   50%
D.   25%
E.   100%
Question #2
Two fruit flies are crossed, resulting in offspring with a 3:1 phenotypic ratio for a particular trait. This suggests:
A.   that one parent had complete dominance for the gene associated with that trait, whereas the other parent had incomplete dominance.
B.   that the parents were both heterozygous for the gene associated with that trait.
C.   that the one parent was heterozygous for the gene associated with that trait and the other parent was homozygous.
D.   incomplete dominance.
E.   that the parents were both homozygous for the gene associated with that trait.
Question #3
Tay-Sachs, which is a recessive lethal disease, results only when individuals possess two copies of the disease-causing allele. Which statement is true about this disease?
A.   Heterozygous individuals only pass on the dominant copy of the allele to offspring.
B.   Heterozygous individuals are more fit than homozygous dominant individuals, so eventually, there will only be heterozygotes in the population.
C.   A homozygous individual can pass on both of the recessive genes for Tay-Sachs.
D.   Heterozygous individuals may pass on their copy of the disease-causing allele to offspring.
E.   All cases of this disease must be caused by new mutations.
Question #4
In a heterozygous state, one allele masks the effect of another. The allele that is masked is referred to as:
A.   dominant.
B.   segregated.
C.   recessive.
D.   true-breeding.
E.   codominant.
Question #5
An autosomal recessive disorder
A.   requires that only one parent be a carrier.
B.   displays its symptoms only in heterozygotes.
C.   is more frequent in males than females.
D.   is dominant in females.
E.   will appear only in children of parents who both carry the gene.
Question #6
The probability of producing a normal child by two parents who are carriers for an autosomal recessive disorder is
A.   100%.
B.   0%.
C.   50%.
D.   25%.
E.   75%.
Question #7
A karyotype cannot determine whether dominant or recessive alleles are present in an individual.
A.   False
B.   True

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