BIOL 2170 Chapter 16
Imagine that you are standing next to Aristotle in early Greece. You both see an older, balding man with visible age spots on his skin. This man also appears to be a wounded soldier, whose left leg has been amputated. What might Aristotle say to you? A: "Because that man is balding, his sons may also be born bald." B: "Because that man has age spots on his skin, his children were likely also born with spots." C: "Because that man is missing a leg, his children are likely also missing legs." D: "Because that man is balding and has age spots, his children will likely go bald and will develop age spots." E: Aristotle would likely say all of these statements to you.
"Because that man is balding and has age spots, his children will likely go bald and will develop age spots."
You are given two populations of true-breeding tomato plants with two traits that sort independently. Using the multiplication rule, how many of the F2 progeny would you expect to have a recessive phenotype for both traits? A: 9/16 B: 6/16 C: 3/16 D: 1/16
1/16
Which of the following represents the expected genotypes of an F2 generation consisting of 8 individuals from an initial cross of a true-breeding black (BB) rabbit and a true-breeding white (bb) rabbit? A: 8 progeny: 0 BB, 0 bb, 8 Bb B: 8 progeny: 8 BB, 0 bb, 0 Bb C: 8 progeny: 4 BB, 4 bb, 0 Bb D: 8 progeny: 2 BB, 2 bb, 4 Bb
8 progeny: 2 BB, 2 bb, 4 Bb
A testcross of an organism of unknown genotype is done when the organism is crossed to an organism that is: A: a heterozygote. B: a dominant homozygote. C: a recessive homozygote. D: All of these choices are correct.
A recessive homozygote.
Which of the following statements is true regarding Hippocrates' theory of trait inheritance? A: This theory influenced later evolutionary biologists, such as Charles Darwin and Jean-Baptiste Lamarck. B: This theory stated that each body part could produce heritable substances that could be passed onto progeny. C: This theory was likely the first to postulate how specific traits are inherited. D: This theory supported the idea that characteristics such as muscle strength can be passed from parents to offspring. E: All of these choices are correct.
All of these choices are correct
Which of the following statements is true regarding phenylketonuria or PKU? A: PKU can result from several different alleles. B: PKU is considered to be a recessive trait. C: Genetic testing can identify whether potential parents are heterozygous for PKU alleles. D: With proper screening and treatment, children with PKU can lead relatively normal lives. E: All of these choices are correct.
All of these choices are correct
The principle of independent assortment states that: A: one set of alleles of a gene pair always assorts with the alleles of another gene pair. B: alleles of a gene pair assort independently of other gene pairs. C: when gametes are formed, the two members of a gene pair will separate equally into gametes. D: when gametes are formed, the two members of a gene pair assort together in gametes.
Alleles of a gene pair assort independently of other gene pairs.
Recall that alleles of a single gene will segregate from one another during anaphase I. When do alleles for two different genes—located on two different chromosomes—segregate? A: anaphase I B: anaphase II C: metaphase I D: metaphase II E: telophase I
Anaphase I
Animals that sexually reproduce are _____ and produce _____ gametes. A: diploid; haploid B: diploid; diploid C: haploid; diploid D: haploid; haploid
Diploid; haploid
Each human gene only has two different alleles—one mutant allele and one "normal" allele. A: true B: false
False
Environmental factors are unlikely to affect variable expressivity in individuals. A: true B: false
False
In Mendel's experiments, his parental pea plants are referred to as the F1 generation, and their progeny are referred to as the P1 generation. A: true B: false
False
The ratio of white to colored chickens that occurs in the F2 generation of a cross between White Leghorn and White Wyandotte chickens is the result of incomplete dominance and variable expressivity. These are the only explanations as to why a ratio would deviate from Mendel's expected 9:3:3:1 ratio. A: true B: false
False
True-breeding plants are typically heterozygous for most genes. A: true B: false
False
In a pedigree: A: females are squares; males are triangles. B: females are circles; males are triangles. C: males are squares; females are triangles. D: males are circles; females are triangles. E: males are circles; females are squares. F: females are circles; males are squares.
Females are circles; males are squares.
Which of the following statements is true regarding Mendel's work? A: He did not use true-breeding pea strains. B: He provided no numerical or statistical data for any of his experiments. C: He focused on a subset of easily discernible traits in pea plants. D: His work utilized several different traits and several different strains of pea plants, some of which were not considered to be true breeding. E: All of these choices are correct.
He focused on a subset of easily discernible traits in pea plants.
A recessive trait is expressed when the genotype is: A: homozygous dominant or heterozygous. B: homozygous recessive or heterozygous. C: heterozygous only. D: homozygous dominant only. E: homozygous recessive only.
Homozygous recessive only.
Why was the theory of blending inheritance eventually disproven? A: It was based on the fact that the phenotypes of progeny of a given cross typically resemble either parent—and never present "intermediate" phenotypes (i.e., such as grey fur). B: It suggested that traits such as blue eyes were recessive, whereas such traits are in fact actually the result of rare dominant mutations arising in populations. C: The theory of blending inheritance suggested that inheritance is a diversifying force, whereas it is actually a homogenizing force. D: Although the theory of blending inheritance accounted for a great deal of variation in a population, the theory of natural selection yielded explanations for every phenotype observed in a population. E: It was eventually disproven by demonstrating segregation of alleles for the inheritance of many traits in diverse types of organisms.
It was eventually disproven by demonstrating segregation of alleles for the inheritance of many traits in diverse types of organisms.
Which of the following is true of blending inheritance? A: Blending inheritance explains the disappearance of a trait several generations after it appeared. B: Blending inheritance leads to an increase in variation over time. C: Blending inheritance allows for rare variants of traits to increase in frequency. D: None of the answer options is correct.
None of the answer options is correct.
What is an allele? A: a group of unrelated genes seen in true breeding stock B: a circular strand of DNA capable of self-replication C: one of several different forms of a gene D: a spontaneous mutation E: the external appearance of an organism
One of several different forms of a gene.
A _____ square is a useful diagram to show the results of a F1 x F1 cross. A: genotype B: dominance C: reciprocal D: Mendelian E: Punnett
Punnett
One of Mendel's most important discoveries was: A: equivalence of reciprocal crosses. B: segregation. C: dominance. D: mutation.
Segregation
Your grandmother has a rare disease for which a new genetic test has just been developed. If you are interested in a genetic test to determine whether you are affected, what would you need to know in order to best interpret your test? A: the degree of variable expressivity if you lack a copy of the affected allele B: the penetrance of disease in people of your genotype C: your father's genotype D: if you have one or two copies of a dominant allele
The penetrance of disease in people of your genotype
For a trait like flower color in snapdragons that is determined by two alleles with incomplete dominance, the offspring of true-breeding parents show an intermediate phenotype. This is also what would be expected of blending inheritance. The difference is that: A: the trait with blending inheritance will gain the variation over time. B: the trait with Mendelian inheritance will lose the variation over time. C: the trait with Mendelian inheritance shows segregation in the F2 generation. D: the trait with blending inheritance shows segregation in the F2 generation.
The trait with Mendelian inheritance shows segregation in the F2 generation.
Although Gregor Mendel's work was not originally considered by his contemporaries to be groundbreaking, Mendel's principles of segregation and independent assortment were "rediscovered" nearly two decades after his death. A: true B: false
True
Darwin believed in the theory of blending inheritance. A: true B: false
True
The addition rule requires which of the following? A: More than one outcome (such as two different genotypes resulting in black fur) can occur simultaneously in an organism. B: Two outcomes (such as having the genotype BB or Bb) are mutually exclusive in an organism.
Two outcomes (such as having the genotype BB or Bb) are mutually exclusive in an organism.
Which of the following statements is true regarding the yellow-seed pea plants of Mendel's work? A: Yellow-seed plants produce copious amounts of chlorophyll. B: Yellow-seed plants have an enzyme that breaks down chlorophyll. C: The yellow seed color of these plants is a recessive trait (compared to green seed color). D: Yellow seeds in these plants only appear in the P1 generation, and never in the F1 generation. E: All of these choices are correct.
Yellow-seed plants have an enzyme that breaks down chlorophyll.