Test 1 Flashcards
Which of the following human cells contain a gene that specifies eye color? A. Cells in the eye B. cells in the heart C. Gametes D. Cells in the eye and gametes E. all of the above
E. all of the above
Genes are inherited factors that determine a characteristic. Alternative forms of a gene are called ___ and are located at a specific place or ____ on a chromosome. The set of genes that an individual organism possesses is it’s _____ compared to the _____ which is the manifestation or appearance of a characteristic.
alleles, locus, genotype, phenotype
The conclusions that Mendel developed about inheritance from his monohybrid crosses between true-breeding pea plants were formalized into the principle of segregation and the concept of dominance. Utilizing this knowledge, how did Mendel know that each of his pea plants carried two alleles encoding a characteristic?
A. The traits for both alleles were observed in a near equal ratio in the F1
B. The traits for both alleles appeared in the F2 progeny
C. By allowing the pea plants to self-fertilize and produce an F3 generation in which the traits for both alleles appeared in a near equal ratio
D. The observation that traits for both alleles appeared in all generations of progeny
E. Through dissection and analysis of a pea plant just after fertilization
B. The traits for both alleles appeared in the F2 progeny
The Principle of Independent Assortment is an extension of the Principle of Segregation.
True or False.
True
In Mendel’s peas, yellow seeds are dominant to green seeds. A pure-breeding yellow plant is crossed with a pure-breeding green plant. All of the offspring are yellow. If one of these yellow offspring is crossed with a green plant, what will be the expected proportion of plants with green seeds in the next generation?
50%
Suppose you were given a purple petunia plant with no information about its parents. Because purple flowers are a dominant trait in petunias, your plant could be either homozygous (PP) or Heterozygous (Pp), but you would not know which. You could determine its genotype by performing a testcross using the plant in question crossed with another petunia plant. Which of the following plants would you use (as a second plant) to perform your testcross? A. PP B. Pp C. pp D. Any of the above would work
C. pp
A chi-square test comparing observed and expected progeny is carried out, and the probability associated with the calculated chi-square value is .76. What does this probability represent? (note: there is no need to look at a table - this is a conceptual question)
A. the probabilty that the correct results were obtained
B. The probability of obtaining the observed numbers
C. the probability of obtaining the expected numbers
D. The probability that the difference between the observed and expected numbers could be due to chance
E. The probability that the difference between the observed and expected numbers is significant.
D. the probability that the difference between the observed and expected numbers could be due to chance.
Dudley has classic hemophilia, an X-linked recessive disease. Which one of the following persons could Dudley have inherited the gene for the disease from? A, his mother's father B. his father's mother C. his father's father D. his sister E. none of the above
A. his mother’s father
What is the sexual morphology of a fruit fly with two X chromosomes and two autosomes - XX AA? A.Male B. Metamale C. intersex D. Female E. Metafemale
D. Female
A teenage girl visits her family doctor because she has never reached menarche. An ultrasound reveals the absence of a uterus and the presence of testes in the abdominal cavity. If chromosome analysis is conducted on cells from this individual, what is the expected sex chromosome composition? A. 45, X B. 46, XY C. 46, XX D. 47, XXY E. 47, XYY
B. 46, XY
Consider the case of a red-green color blind Klinefelter male whose parents both have normal vision. If this genetic condition is the result of nondisjunction, when did it occur? A. Spermatogenesis, Meiosis I B. Oogenesis, Meiosis I C.Spermatogenesis, Meiosis II D. Oogenesis, Meiosis II E. None of the above
D. Oogenesis, Meiosis II
How many Barr bodis are found in the somatic cells of an individual with the following sex chromosomes - XXXY? A. 4 B. 3 C. 2 D. 1 E. 0
C. 2
Anhidrotic ectodermal dysplasia is a X-linked recessive disorder in humans characterized by small teeth, no sweat glands and sparse body hair. The trait is usualyy seen in men but women who are heterozygous carriers of the trait often have irregular patches of skin with few or no sweat glads. Which of the reasons below would explain why women who are heterozygous carriers of a recessive gene for this condition would have irregular patches of skin lacking sweat glads.
A. Dosage compensation in humans doubles the amount of protein produced by the X chromosome in males to match the amount of protein produced off of both X chromosomes in females allowing for the expression of proteins on both X chromosomes, including those responsible for the disorder.
B. The process of X inactivation was faulty in these females leaving both X chromosomes active
C. The process of X inactivation renders these females functionally hemizygous at the cellular level for X-linked genes
D. None of the above
C. The process of X inactivation renders these females functionally hemizygous at the cellular level for X-linked genes.
_____ is the degree of which a trait is expressed. _____ is the percentage of individuals having a particular genotype that expresses the associated phenotype.
expressivity, penetrance
Bridges studied the eye color of fruit flies. He hypothesized that white-eye females (XwXwY) and red-eyed males (X+Y) in the F1 generation result from nondisjunction in an XwXwY female. In the context of this hypothesis, which of the following choices below represents the gametes produced by the white-eyed female when nondisjunction occurs? A. XwY and Xw B.XwXw and Y C. XwXw and Xw D. X+ and Y E. Xw and Y
B. XwXw and Y
