Bio Chapter 9

Which of the following statements best represents the theory of pangenesis developed by Hippocrates? A. Particles called pangenes, which originate in each part of an organism's body, collect in the sperm or eggs and are passed on to the next generation. B. Pregnancy is a spontaneous event, and the characteristics of the offspring are determined by the gods. C. Heritable traits are influenced by the environment and the behaviors of the parents. D. Offspring inherit the traits of either the mother or the father, but not both.

Which of the following statements regarding hypotheses about inheritance is false? A. The theory of pangenesis incorrectly suggests that reproductive cells receive particles from somatic cells. B. The blending hypothesis suggests that all of the traits of the offspring come from either the mother or the father. C. Contrary to the theory of pangenesis, somatic cells do not influence eggs or sperm. D. The blending hypothesis does not explain how traits that disappear in one generation can reappear in later generations.

Amniocentesis and chorionic villus sampling allow for ________ and ________ of the fetus so that it can be tested for abnormalities. A. direct observation; biochemical testing B. imaging; karyotyping C. karyotyping; biochemical testing D. sexing; imaging

Which of the following statements regarding prenatal testing is false? A. Results from chorionic villus sampling come faster than those from amniocentesis. B. Chorionic villus sampling is typically performed later in the pregnancy than amniocentesis. C. Ultrasound imaging has no known risk. D. Chorionic villus sampling and amniocentesis are usually reserved for pregnancies with higher than usual risks of complications.

Which of the following statements regarding genetic testing is false? A. Carrier testing helps determine whether a person carries a potentially harmful disorder. B. Most human genetic diseases are treatable if caught early. C. Genetic testing before birth requires the collection of fetal cells. D. The screening of newborns can catch inherited disorders right after birth.

Mendel conducted his most memorable experiments on A. peas. B. roses. C. guinea pigs. D. fruit flies.

Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as A. monohybrid crosses. B. true-breeding. C. hybrids. D. the F2 generation.

Which of the following statements regarding cross-breeding and hybridization is false? A. The offspring of two different varieties are called hybrids. B. The hybrid offspring of a cross are the P1 generation. C. The parental plants of a cross are the P generation. D. The hybrid offspring of an F1 cross are the F2 generation.

You prepare a karyotype from a cell from an unknown organism. Upon analysis, you find 22 pairs of chromosomes that are each of equal length, and also a single pair that has one chromosome longer than the other. What can you conclude from this information? A. The organism that this cell came from is likely a male. B. This cell is likely haploid. C. The organism that this cell came from has a genetic disease. D. The organism that this cell came from is likely a female.

You are looking at an unknown cell under a microscope that has 22 chromosomes plus two X chromosomes. Which of the following is the most likely identity of this cell? A. an epithelial cell from a male chicken B. an egg from a human female C. a skin cell from a human female D. an eye cell from a female grasshopper

All the offspring of a cross between a black-eyed Mendelian and an orange-eyed Mendelian have black eyes. What is the expected phenotypic ratio of a cross between two orange-eyed Mendelian? A. 0 black-eyed:1 orange-eyed B. 1 black-eyed:0 orange-eyed C. 1 black-eyed:3 orange-eyed D. 3 black-eyed:1 orange-eyed

A monohybrid cross is A. a breeding experiment in which the parental varieties differ in only one character. B. a breeding experiment in which the parental varieties have only one prominent trait. C. the second generation of a self-fertilized plant. D. a breeding experiment in which the parental varieties have only one trait in common.

Which of the following statements regarding genotypes and phenotypes is false? A. Alleles are alternate forms of a gene. B. An organism with two different alleles for a single trait is said to be homozygous for that trait. C. The expressed physical traits of an organism are called its phenotype. D. The genetic makeup of an organism constitutes its genotype.

Research since Mendel's time has established that the law of segregation of genes during gamete formation A. applies to all sexually reproducing organisms. B. is invalid. C. applies to all asexually reproducing organisms. D. applies to all forms of life.

In giraffes, long necks (N), long legs (L), dark spots (D), and the ability to digest meat (M) are all dominant traits. What possible genotype could a long-necked, short-legged, light-spotted, meat-digesting giraffe have? A. NNllddmm B. nnLLddMM C. NNLLDdMm D. NnllddMM

Which plants in this figure must all be heterozygous? A. white-flowered plants in the P generation B. purple-flowered plants in the F2 generation C. purple-flowered plants in the P generation D. purple-flowered plants in the F1 generation

The alleles of a gene are found at ________ chromosomes. A. different loci on nonhomologous B. different loci on homologous C. the same locus on homologous D. the same locus on nonhomologous

The phenotypic ratio resulting from a dihybrid cross of two heterozygote individuals showing independent assortment is expected to be A. 3:1 B. 9:3:3:1 C. 1:2:1 D. 9:1:1:3

If A is dominant to a and B is dominant to b, what is the expected phenotypic ratio of the cross AaBb × AaBb? A. 16:0:0:0 B. 9:3:3:1 C. 1:1:1:1 D. 8:4:2:2

Mendel's law of independent assortment states that A. each pair of alleles segregates independently of the other pairs of alleles during gamete formation. B. chromosomes sort independently of each other during mitosis and meiosis. C. genes are sorted concurrently during gamete formation. D. independent sorting of genes produces polyploid plants under some circumstances.

Imagine that we mate two black Labrador dogs with normal vision and find that three of the puppies are like the parents, but one puppy is chocolate with normal vision and another is black with PRA (progressive retinal atrophy, a serious disease of vision). We can conclude that A. the same alleles that control coat color can also cause PRA. B. the alleles for color and vision segregate independently during gamete formation. C. both of the parents are homozygous for both traits. D. the alleles for color and vision segregate dependently during gamete formation.

Below are two statements. Which (if any) applies to the law of segregation? Which (if any) applies to the law of independent assortment? I: Phenotypes for long tails and big eyes are inherited separately in lab mice. II: A baby mouse inherits a maternal red eye allele and a paternal black eye allele. A. A: segregation; B: independent assortment B. A: independent assortment; B: independent assortment C. A: segregation; B: segregation D. A: independent assortment; B: segregation

In some cats, black coat color (B) is dominant over brown (b) and a striped fur pattern (S) is dominant over a marbled fur pattern (s). You rescued a black striped cat from an animal shelter but could not determine its exact genotype. To do so, you mated the cat with a brown marbled cat. The mating produced 3 brown marbled, 2 brown striped, 2 black marbled, and 3 black striped. Immediately, you concluded the genotype of your rescued cat was A. BBSs. B. BbSS. C. BBSS. D. BbSs.

During a summer study abroad program, you travelled to Austria to study genetics at the University of Vienna. While you were there, a momentous discovery was made: some of Gregor Mendel's original lab books and notes were found to be buried outside of the abbey where he lived. It just so happened that the professor you were working with obtained copies of these notes and enlisted your help to decipher them. You hired a translator to translate Mendel's notes from Czech to English, and using your knowledge of modern genetics (which Mendel did not have!) you were able to construct a partial Punnett square (shown below). Because the notebook was damaged from being buried for so long, this is the only information that you have regarding a cross that Mendel must have performed. Your professor has tasked you with figuring out more about this experiment. In pea plants, round peas are dominant (R) and shriveled peas are recessive (r) and yellow peas (shown as light gray in Punnett square) are dominant (Y) and green peas (dark gray) are recessive (y). Using this information and the partial Punnett square above, what were the phenotypes of the parental plants that were used in this cross by Mendel? A. Rryy and rrYy B. Rryy and RrYy C. RrYy and RrYy D. RRyy and rryy

During a summer study abroad program, you travelled to Austria to study genetics at the University of Vienna. While you were there, a momentous discovery was made: some of Gregor Mendel's original lab books and notes were found to be buried outside of the abbey where he lived. It just so happened that the professor you were working with obtained copies of these notes and enlisted your help to decipher them. You hired a translator to translate Mendel's notes from Czech to English, and using your knowledge of modern genetics (which Mendel did not have!) you were able to construct a partial Punnett square (shown below). Because the notebook was damaged from being buried for so long, this is the only information that you have regarding a cross that Mendel must have performed. Your professor has tasked you with figuring out more about this experiment. In pea plants, round peas are dominant (R) and shriveled peas are recessive (r), and yellow peas (shown as light gray in Punnett square) are dominant (Y) and green peas (dark gray) are recessive (y). Using this information and the partial Punnett square above, what genotype should be listed in the square labeled A? A. RrYy B. RRyy C. rrYy D. RRYY RRYY

During a summer study abroad program, you travelled to Austria to study genetics at the University of Vienna. While you were there, a momentous discovery was made: some of Gregor Mendel's original lab books and notes were found to be buried outside of the abbey where he lived. It just so happened that the professor you were working with obtained copies of these notes and enlisted your help to decipher them. You hired a translator to translate Mendel's notes from Czech to English, and using your knowledge of modern genetics (which Mendel did not have!) you were able to construct a partial Punnett square (shown below). Because the notebook was damaged from being buried for so long, this is the only information that you have regarding a cross that Mendel must have performed. Your professor has tasked you with figuring out more about this experiment. In pea plants, round peas are dominant (R) and shriveled peas are recessive (r,) and yellow peas (shown as light gray in Punnett square) are dominant (Y) and green peas (dark gray) are recessive (y). Using this information and the partial Punnett square above, what phenotype should be in the square labeled B? A. round and green B. shriveled and yellow C. shriveled and green D. round and yellow

During a summer study abroad program, you travelled to Austria to study genetics at the University of Vienna. While you were there, a momentous discovery was made: some of Gregor Mendel's original lab books and notes were found to be buried outside of the abbey where he lived. It just so happened that the professor you were working with obtained copies of these notes and enlisted your help to decipher them. You hired a translator to translate Mendel's notes from Czech to English, and using your knowledge of modern genetics (which Mendel did not have!) you were able to construct a partial Punnett square (shown below). Because the notebook was damaged from being buried for so long, this is the only information that you have regarding a cross that Mendel must have performed. Your professor has tasked you with figuring out more about this experiment. In pea plants, round peas are dominant (R) and shriveled peas are recessive (r), and yellow peas (shown as light gray in Punnett square) are dominant (Y) and green peas (dark gray) are recessive (y). Using this information and the partial Punnett square above, what is the phenotypic ratio of the offspring pea plants in this Punnett square? A. 1:1:1:1 B. 12:1:1:4 C. 9:3:3:1 D. 3:3:1:1

A testcross is A. a mating between an individual of unknown genotype and an individual heterozygous for the trait of interest. B. a mating between two individuals of unknown genotype. C. a mating between two individuals heterozygous for the trait of interest. D. a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest.

Using a six-sided die, what is the probability of rolling either a 5 or a 6? A. 1/6 × 1/6 = 1/36 B. 1/6 + 1/6 = 1/3 C. 1/6 D. 1/6 + 1/6 = 2/3

Assuming that the probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couple's first-born child will be female and that their second-born child will be male? A. 75% B. 50% C. 20% D. 25%

Suppose that an elephant with the genotype EEFfggHh reproduces with an elephant with the genotype eeFFGgHh. What is the probability that a baby elephant (called a calf) would have the genotype EeFFGghh? A. 1/16 B. 1/32 C. 1/256 D. 1/64

Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes? A. Dd and Dd B. dd and dd C. Dd and DD D. DD and dd

A carrier of a genetic disorder who does not show symptoms is most likely to be ________ to transmit it to offspring. A. homozygous for the trait and able B. heterozygous for the trait and unable C. heterozygous for the trait and able D. homozygous for the trait and unable

Most genetic disorders of humans are caused by A. a mutation that occurs in the egg, sperm, or zygote. B. recessive alleles. C. dominant alleles. D. multiple alleles.

Most people afflicted with recessive disorders are born to parents who were A. not affected at all by the disease. B. subjected to some environmental toxin that caused the disease in their children. C. both affected by the disease. D. slightly affected by the disease, showing some but not all of the symptoms.

Which of the following statements best explains why dominant alleles that cause lethal disorders are less common than recessive alleles that cause lethal disorders? A. Most individuals carrying a lethal dominant allele have the disorder and die before they reproduce, whereas individuals carrying a lethal recessive allele are more likely to be healthy and reproduce. B. Unlike lethal disorders caused by recessive alleles, lethal disorders caused by dominant alleles usually cause the death of the embryo. C. Lethal disorders caused by dominant alleles are usually more severe than lethal disorders caused by recessive alleles. D. The presence of a lethal dominant allele causes sterility.

Cats normally have a total of 18 toes, 5 on each front paw and 4 on each back paw. But some cats express the dominant phenotype for polydactyly, which results in the development of extra toes on one or more paws. Jake, a Canadian tabby cat, has 28 toes and is recognized by the Guinness Book of World Records as the cat with the most toes. Suppose that Jake mates with a female cat, Lucy, who has 18 total toes. Over several years, they have multiple litters and a total of 16 kittens (10 males and 6 females). The total number of toes on each kitten ranges from 21 to 25. If we use the letter P to represent the polydactyly gene, what is Jake's genotype? A. Pp B. pp C. PP D. You cannot determine Jake's genotype from this information.

Cats normally have a total of 18 toes, 5 on each front paw and 4 on each back paw. But some cats express the dominant phenotype for polydactyly, which results in the development of extra toes on one or more paws. Jake, a Canadian tabby cat, has 28 toes and is recognized by the Guinness Book of World Records as the cat with the most toes. Suppose that Jake mates with a female cat, Lucy, who has 18 total toes. Over several years, they have multiple litters and a total of 16 kittens (10 males and 6 females). The total number of toes on each kitten ranges from 21 to 25. One of Jake and Lucy's kittens mates with another cat that has 18 total toes. What is the probability that one of their offspring would have 18 total toes? A. 50% B. 100% C. 0% D. 75%

Cats normally have a total of 18 toes, 5 on each front paw and 4 on each back paw. But some cats express the dominant phenotype for polydactyly, which results in the development of extra toes on one or more paws. Jake, a Canadian tabby cat, has 28 toes and is recognized by the Guinness Book of World Records as the cat with the most toes. Suppose that Jake mates with a female cat, Lucy, who has 18 total toes. Over several years, they have multiple litters and a total of 16 kittens (10 males and 6 females). The total number of toes on each kitten ranges from 21 to 25. Along with having a variable number of toes, some kittens from Jake and Lucy's litter had a white spot on their nose. In fact, out of the 16 kittens, all 10 males had the white spot, but none of the 6 females had the white spot. Jake has a white spot on his nose, but Lucy does not. What can you conclude from this information? A. A sex-linked gene that controls the expression of the white spot is found on the X chromosome. B. The genes for the white spot and for polydactyly are not linked. C. A sex-linked gene that controls the expression of the white spot is found on the Y chromosome. D. The genes for the white spot and for polydactyly are linked.

For most sexually reproducing organisms, Mendel's laws A. help us understand the global geographic patterns of genetic disease. B. can predict whether offspring will be male or female with 100% accuracy. C. explain the biological mechanisms behind why certain genes are dominant or recessive. D. cannot strictly account for the patterns of inheritance of many traits.

All the offspring of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is ________ to the allele for white flowers. A. codominant B. dominant C. recessive D. incompletely dominant

Imagine that beak color in a finch species is controlled by a single gene. You mate a finch homozygous for orange (pigmented) beak with a finch homozygous for ivory (unpigmented) beak and get numerous offspring, all of which have a pale, ivory-orange beak. This pattern of color expression is most likely to be an example of A. codominance. B. pleiotropy. C. incomplete dominance. D. polygenic inheritance.

Which of the following is an example of incomplete dominance in humans? A. hypercholesterolemia B. ABO blood groups C. albinism D. skin color

According to this figure, heterozygotes for this form of hypercholesterolemia suffer from the disease because they A. don't produce enough LDL receptors. B. don't produce any LDL receptors. C. produce too many LDL receptors. D. produce an abnormally shaped LDL receptor.

The expression of both alleles for a trait in a heterozygous individual illustrates A. codominance. B. polygenic inheritance. C. incomplete dominance. D. pleiotropy.

A person with AB blood illustrates the principle of A. pleiotropy. B. codominance. C. incomplete dominance. D. polygenic inheritance.

Justin has type A blood and his wife Brittany has type B blood. Justin's parents both have type AB blood, and Brittany's parents also both have type AB blood. What are the chances that Justin and Brittany's son Theodore has type A blood? A. 75% B. 25% C. 100% D. 0%

A man and his wife are having trouble having a baby. Using modern technologies, the woman's eggs are removed, fertilized with her husband's sperm, and implanted into her uterus. The procedure is successful, and the woman gives birth to a healthy baby boy. After a while, though, they discover that their son is colorblind and has blood type O. The woman claims that the child can't be theirs since she has blood type A and her husband has type B. Also, neither parent is colorblind, although one grandparent (the woman's father) is also colorblind. As a genetic counselor, you would explain to the parents that A. each parent could have contributed one recessive allele, resulting in type O blood. B. the eggs must have been accidentally switched, since the baby's blood type has to match one of his parents. C. the eggs must have been accidentally switched, since a type A parent and a type B parent can have any type children except O. D. it is possible for the baby to have type O blood, since type O is inherited through a dominant allele.

Which of the following statements is false? A. The four blood types result from various combinations of the three different ABO alleles. B. The impact of a single gene on more than one character is called pleiotropy. C. ABO blood groups can provide evidence of paternity. D. Incomplete dominance supports the blending hypothesis.

Which of the following statements regarding sickle-cell disease is false? A. All of the symptoms of sickle-cell disease result from the actions of just one allele. B. Sickle-cell disease causes white blood cells to be sickle-shaped. C. Persons who are heterozygous for sickle-cell disease are also resistant to malaria. D. About one in 10 African Americans is a carrier of sickle-cell disease.

Sickle-cell disease is an example of A. codominance and pleiotropy. B. codominance and multiple alleles. C. multiple alleles, pleiotropy, and blended inheritance. D. multiple alleles and pleiotropy.

Which of the following terms refers to a situation where a single phenotypic character is determined by the additive effects of two or more genes? A. polygenic inheritance B. codominance C. pleiotropy D. incomplete dominance

Which of the following is essentially the opposite of pleiotropy? A. polygenic inheritance B. codominance C. multiple alleles D. incomplete dominance

Blood samples are taken from the heel of newborn babies to test for a mutation in the PKU gene, which, if left untreated and in severe cases, can lead to mental retardation, reduced skin pigmentation, and seizures. Which concept is being illustrated by this example? A. codominance B. polygenic inheritance C. incomplete dominance D. pleiotropy

The individual features of all organisms are the result of A. the environment. B. genetics. C. the environment and individual needs. D. genetics and the environment.

The chromosome theory of inheritance states that A. the behavior of chromosomes during meiosis and fertilization accounts for patterns of inheritance. B. chromosomes that exhibit mutations are the source of genetic variation. C. humans have 46 chromosomes. D. the behavior of chromosomes during mitosis accounts for inheritance patterns.

If independent assortment did not occur, which of the following would be true? A. Genes for two different traits would be inherited together as a pair. B. Each sperm and egg would carry more than one allele for a specific gene. C. A dihybrid cross of heterozygous individuals would yield four different phenotypes. D. Meiosis II would not be required to produce gametes, as meiosis I would be sufficient.

Genes located close together on the same chromosomes are referred to as ________ genes and generally ________. A. homologous; are inherited together B. linked; do not sort independently during meiosis C. codependent; do not sort independently during meiosis D. linked; sort independently during meiosis

Linked genes generally A. show incomplete dominance. B. show pleiotropy. C. do not follow the laws of independent assortment. D. reflect a pattern of codominance.

You conduct a dihybrid cross. A ________ ratio would make you suspect that the genes are linked. A. 3:1 B. 12:1:1:4 C. 9:3:3:1 D. 1:1:1:1

Crossing over ________ genes into assortments of ________ not found in the parents. A. combines linked; genes B. recombines linked; alleles C. recombines unlinked; genes D. combines unlinked; alleles

The mechanism that "breaks" the linkage between linked genes is A. pleiotropy. B. crossing over. C. codominance. D. independent assortment.

Which of the following kinds of data could be used to map the relative position of three genes on a chromosome? A. the frequencies with which the genes are inherited from the mother and from the father B. the frequencies with which the genes exhibit incomplete dominance over each other C. the frequencies with which the corresponding traits occur together in offspring D. the frequencies of mutations in the genes

You are trying to determine the linkage map of a series of genes, X, Y, and Z, from Caenorhabditis elegans, a nematode worm commonly used in scientific research. From doing several crossover experiments, you know that the recombination frequency between X and Y is 11.5%, between Y and Z is 13%, and between X and Z is 25%. What is a possible sequence of these genes? A. X−Y−Z B. X−Z−Y C. Y−Z−X D. Z−X−Y

What is the normal complement of sex chromosomes in a human male? A. two X chromosomes and one Y chromosome B. one Y chromosome C. one X chromosome and one Y chromosome D. two Y chromosomes

The sex chromosome complement of a normal human female is A. XX B. XO C. YY D. XY

How many sex chromosomes are in a human gamete? A. three B. two C. four D. one

How is sex determined in most ants and bees? A. by the number of chromosomes B. by the Z-W system C. by the X-Y system D. by the size of the sex chromosome

Given the sex determination system in bees, we can expect that A. male and female bees will produce sperm and eggs by meiosis. B. male and female bees will produce sperm and eggs by mitosis. C. female bees will produce eggs by meiosis, whereas male bees will produce sperm by mitosis. D. female bees will produce eggs by mitosis, whereas male bees will produce sperm by meiosis.

What is meant by the statement that "male bees are fatherless"? A. Male bees develop from unfertilized eggs. B. Male bees are produced by budding. C. The queen bee's mate dies before the male eggs hatch. D. Male bees don't play a role in the rearing of bee young.

Any gene located on a sex chromosome A. will exhibit codominance. B. will exhibit pleiotropy. C. is called a recessive gene. D. is called a sex-linked gene.

Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female fruit fly because A. the male chromosome is more fragile than the female chromosome. B. the male's phenotype results entirely from his single X-linked gene. C. males are haploid. D. the male chromosome is more susceptible to mutations.

A colorblind woman marries a man who is not colorblind. All of their sons, but none of their daughters, are colorblind. Which of the following statements correctly explains these results? A. The gene for color vision is incompletely dominant to the gene for sex determination. B. The gene for color vision is found on the Y chromosome. C. The gene for color vision is found on the X chromosome. D. The gene for color vision is codominant with the gene for sex determination.

Sex-linked conditions are more common in men than in women because A. the genes associated with the sex-linked conditions are linked to the Y chromosome, which determines maleness. B. the sex chromosomes are more active in men than in women. C. men acquire two copies of the defective gene during fertilization. D. men need to inherit only one copy of the recessive allele for the condition to be fully expressed.

A man and his wife are having trouble having a baby. Using modern technologies, the woman's eggs are removed, fertilized with her husband's sperm, and implanted into her uterus. The procedure is successful, and the woman gives birth to a healthy baby boy. After a while, though, they discover that their son is colorblind and has blood type O. The woman claims that the child can't be theirs since she has blood type A and her husband has type B. Also, neither parent is colorblind, although one grandparent (the woman's father) is also colorblind. In regard to the baby's colorblindness, a sex-linked recessive trait, you explain that A. since colorblindness is sex-linked, a son can inherit colorblindness if his mother has the recessive colorblindness allele. B. the baby's father must have a recessive allele for colorblindness. C. the eggs must have been accidentally switched, since males inherit sex-linked traits only from their fathers. D. colorblindness often appears randomly, even if neither parent is colorblind.

According to scientists, about what percentage of men currently living in Central Asia may be descended from the Mongolian ruler Genghis Khan? A. 8% B. 25% C. 4% D. 40%

Female inheritance patterns cannot be analyzed by simply studying the X chromosome because A. the X chromosome is too large to analyze effectively. B. the X chromosome is obtained from both father and mother. C. one X chromosome is deactivated in females. D. the X chromosome sometimes exchanges genetic information with the Y chromosome.