biology 9
A monohybrid cross is a breeding experiment in which the parental varieties differ in only one character. a breeding experiment in which the parental varieties have only one trait in common. a breeding experiment in which the parental varieties have only one prominent trait. the second generation of a self-fertilized plant.
a
A single allele that controls more than one character is said to be _____. pleiotropic linked polygenic autotrophic
a
A testcross is a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest. a mating between two individuals heterozygous for the trait of interest. a mating between two individuals of unknown genotype. a mating between an individual of unknown genotype and an individual heterozygous for the trait of interest.
a
A woman and her male partner have normal color vision. However, her father and her first son are colorblind. What is her genotype? Use C as the gene for colorblindness. XCXc XCXC XCY XcXc
a
According to scientists, about what percentage of men currently living in Central Asia may be descended from the Mongolian ruler Genghis Khan? 8% 4% 25% 40%
a
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. incompletely dominant dominant recessive codominant
a
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? 25% 75% 20% 50%
a
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? pleiotropy polygenic inheritance incomplete dominance codominance
a
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? Dd and Dd dd and dd Dd and DD DD and dd
a
Given the sex determination system in bees, we can expect that bees will produce eggs by meiosis, whereas male bees will produce sperm by mitosis. female bees will produce eggs by mitosis, whereas male bees will produce sperm by meiosis. male and female bees will produce sperm and eggs by meiosis. male and female bees will produce sperm and eggs by mitosis.
a
In Morgan's testcross of a gray-bodied, long-winged heterozygous female Drosophila with a homozygous recessive black-bodied, vestigial-winged male, the following offspring were obtained: 965 gray body, long wing; 944 black body, vestigial wing; 206 gray body, vestigial wing; 185 black body, long wing. Focusing only on the recombinant classes (gray body, vestigial wing and black body, long wing), the numbers of offspring of each type are similar (206 and 185). What accounts for the similar number of offspring of each recombinant phenotype? Crossing over between chromosomes is reciprocal, so whenever a recombinant chromosome of one type is produced, there's a recombinant of the opposite type that is also produced. Because the genes for body color and wing size are linked, they are always inherited together. Segregation occurs reciprocally, so there are always equal numbers of each type of chromosome combination. Independent assortment of chromosomes occurs reciprocally, so there are always equal numbers of each type of chromosome combination.
a
Linked genes generally do not follow the laws of independent assortment. reflect a pattern of codominance. show pleiotropy. show incomplete dominance.
a
Many genetic disorders can be detected before birth. Procedures include _____, which is noninvasive, or _____, which allows the chromosomes of the fetus to be examined. Alternatively, maternal blood samples can be taken and tested for _____. ultrasound imaging ... chorionic villus sampling ... AFP amniocentesis ... AFP ... chorionic villus sampling amniocentesis ... ultrasound imaging ... chorionic villus sampling ultrasound imaging ... AFP ... amniocentesis
a
Research since Mendel's time has established that the law of segregation of genes during gamete formation applies to all sexually reproducing organisms. applies to all forms of life. is invalid. applies to all asexually reproducing organisms.
a
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? 1/16 1/256 1/32 1/64
a
The chromosome theory of inheritance states that the behavior of chromosomes during meiosis and fertilization accounts for patterns of inheritance. humans have 46 chromosomes. the behavior of chromosomes during mitosis accounts for inheritance patterns. chromosomes that exhibit mutations are the source of genetic variation.
a
The individual features of all organisms are the result of The individual features of all organisms are the result of genetics and the environment. the environment. genetics. the environment and individual needs.
a
Two parents of mixed ethnicity have twins, one of which is born white and one of which is born black. This is because of _____. the polygenic nature of skin color genes the inheritance of two linked skin color genes the pleiotropic effects of skin color genes exposure to sunlight
a
What is meant by the statement that "male bees are fatherless"? Male bees develop from unfertilized eggs. The queen bee's mate dies before the male eggs hatch. Male bees don't play a role in the rearing of bee young. Male bees are produced by budding.
a
Which of the following kinds of data could be used to map the relative position of three genes on a chromosome? the frequencies with which the corresponding traits occur together in offspring the frequencies with which the genes exhibit incomplete dominance over each other the frequencies with which the genes are inherited from the mother and from the father the frequencies of mutations in the genes
a
A large and increasing number of genetic tests are available to prospective parents and children. Even as these testing methods become more and more sophisticated, what is one thing technology will never solve? the ability to test cells taken from embryos before implantation into the uterus the ability to prescribe the correct course of action based on test results the ability to test embryos before the fourth week of pregnancy the ability to test fetuses before the tenth week of pregnancy
b
A person with AB blood illustrates the principle of polygenic inheritance. codominance. incomplete dominance. pleiotropy.
b
A woman who is a carrier of hemophilia marries a man affected with hemophilia. What percentage of their sons and daughters is expected to have hemophilia? 0% of sons and 50% of daughters 50% of sons and 50% of daughters 100% of sons and 50% of daughters 50% of sons and 0% of daughters
b
Any gene located on a sex chromosome is called a recessive gene. is called a sex-linked gene. will exhibit pleiotropy. will exhibit codominance.
b
Because it is passed essentially intact from father to son, Y chromosome research has been particularly useful in improving our understanding of __________. pleiotropy recent human evolution X-linked human diseases chromosome disorders
b
Flower color in snapdragons is an example of incomplete dominance. If a red-flowered plant is crossed with a white-flowered plant, the F1 generation has pink flowers. If a pink-flowered plant is crossed with another pink-flowered plant, the expected progeny plants will be __________. 100% red 25% red, 50% pink, and 25% white 50% pink and 50% red 100% pink
b
Human genetic disorders _____. are almost always life-threatening are most often recessive are most often dominant are almost never observed in modern societies
b
If A is dominant to a and B is dominant to b, what is the expected phenotypic ratio of the cross AaBb × AaBb? 1:1:1:1 9:3:3:1 16:0:0:0 8:4:2:2
b
If each parent can produce 100 genetically distinct gametes, how many genetically distinct offspring can two parents produce? 1,000 10,000 100 200
b
If one parent is blood type AB and the other is type O, what fraction of their offspring are expected to have blood type A? O 0.5 0.75 1.0
b
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 the same alleles that control coat color can also cause PRA. the alleles for color and vision segregate independently during gamete formation. the alleles for color and vision segregate dependently during gamete formation. both of the parents are homozygous for both traits.
b
In a monohybrid cross, F2 refers to __________. the original mating pair the second filial generation, or the "grandchildren" of the original mating pair the 1st filial generation the grandparents of the 1st generation
b
John and Jane are planning a family, but each has a brother who has sickle-cell disease, so they are concerned that their children may develop sickle-cell disease. Neither John, Jane, nor their respective parents have the disease. They consult a genetic counselor who tells them that __________. there is no chance that any of their children will have sickle-cell disease it's possible that none of their children will have the disease, but blood tests on them both will be required to make sure all of their children will have sickle-cell disease one of four of their children can be expected to have sickle-cell disease
b
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? 25% 0% 100% 75%
b
Most people afflicted with recessive disorders are born to parents who were subjected to some environmental toxin that caused the disease in their children. not affected at all by the disease. slightly affected by the disease, showing some but not all of the symptoms. both affected by the disease.
b
The existence of rare XY individuals who are phenotypically normal women was instrumental in learning about human sex determination. Maleness is determined by the SRY gene found on the Y chromosome. How is it possible to be an XY woman? A portion of the Y chromosome containing SRY is duplicated. The SRY locus of the Y chromosome is deleted. The SRY locus of the Y chromosome has translocated (moved) to an autosome (a chromosome other than a sex chromosome). The SRY locus changed position on the Y chromosome
b
The expression of both alleles for a trait in a heterozygous individual illustrates pleiotropy. codominance. polygenic inheritance. incomplete dominance.
b
The mechanism that "breaks" the linkage between linked genes is codominance. crossing over. independent assortment. pleiotropy.
b
The phenotypic ratio resulting from a dihybrid cross of two heterozygote individuals showing independent assortment is expected to be 3:1 9:3:3:1 1:2:1 9:1:1:3
b
The sex chromosome complement of a normal human female is XO. XX. XY. YY.
b
Two individuals decide to have children. The expected blood group genotypes are 50% of blood type A, and 25% each of blood types AB and B. What genotypes are the parents? IB i x IA IB IA i x IA IB IA i x ii IA i x IB i
b
Which of the following statements best represents the theory of pangenesis developed by Hippocrates? Heritable traits are influenced by the environment and the behaviors of the parents. Pregnancy is a spontaneous event, and the characteristics of the offspring are determined by the gods. 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. Offspring inherit the traits of either the mother or the father, but not both.
b
Which of the following statements is false? Which of the following statements is false? ABO blood groups can provide evidence of paternity. Incomplete dominance supports the blending hypothesis. The four blood types result from various combinations of the three different ABO alleles. The impact of a single gene on more than one character is called pleiotropy.
b
Which of the following statements regarding cross-breeding and hybridization is false? The offspring of two different varieties are called hybrids. The hybrid offspring of a cross are the P1 generation. The hybrid offspring of an F1 cross are the F2 generation. The parental plants of a cross are the P generation.
b
Which of the following statements regarding cross-breeding and hybridization is false? The offspring of two different varieties are called hybrids. The hybrid offspring of a cross are the P1 generation. The hybrid offspring of an F1 cross are the F2 generation. The parental plants of a cross are the P generation.
b
Which of the following statements regarding sickle-cell disease is false? Persons who are heterozygous for sickle-cell disease are also resistant to malaria. Sickle-cell disease causes white blood cells to be sickle-shaped. All of the symptoms of sickle-cell disease result from the actions of just one allele. About one in 10 African Americans is a carrier of sickle-cell disease.
b
You cross two fruit trees. One tree produces lemons with spiky leaves. The other produces limes with smooth leaves. Your F1 generation produces lemons with smooth leaves and spiky leaves. What are the genotypes of the parents? L = lemons; l = limes; S = smooth leaf; s = spiky leaf. LLSs and LLss LLss and llSs LlSs and LlSs Llss and llSs
b
As shown in the figure below, at what point in meiosis do the chromosomes segregate from one another? metaphase I interphase anaphase I prophase I
c
Crossing over ________ genes into assortments of ________ not found in the parents. recombines unlinked; genes combines unlinked; alleles recombines linked; alleles combines linked; genes
c
If independent assortment did not occur, which of the following would be true? Meiosis II would not be required to produce gametes, as meiosis I would be sufficient. A dihybrid cross of heterozygous individuals would yield four different phenotypes. Genes for two different traits would be inherited together as a pair. Each sperm and egg would carry more than one allele for a specific gene.
c
Imagine you're counseling a couple who have undergone carrier screening for Tay-Sachs disease. The man is a carrier, and the woman does not carry the Tay-Sachs allele. How should you advise them? They should be informed that if they conceive a child, the child will have Tay-Sachs disease. They should be informed that if they have a child, there is a 25% chance that the child will have Tay-Sachs disease. They should be informed that if they have a child, the child will not have Tay-Sachs disease but will have a 50% chance of being a carrier of the Tay-Sachs allele. They should be informed that if they have a child, there is a 50% chance that the child will have Tay-Sachs disease.
c
In a particular species of mammal, black hair (B) is dominant to green hair (b), and red eyes (R) are dominant to white eyes (r). When a BbRr individual is mated with a bbrr individual, offspring are produced in a ratio of 5 black hair and red eyes : 5 green hair and white eyes : 1 black hair and white eyes : 1 green hair and red eyes. Which of these explanations accounts for this ratio? The expected results did not take genetic recombination into account. The genes for hair color and the genes for eye color are carried on different chromosomes. The genes for hair color and eye color are linked. Green-haired individuals have a higher prenatal mortality than black-haired individuals.
c
In breeding pure-breeding large and small strains of mice, you cross individuals of each strain and note that their offspring are intermediate in size. Two models (explanations) to account for this result are (1) that body size in these strains is due to one gene with alleles that show incomplete dominance and (2) that body size is a polygenic trait. How could you distinguish between these models? Body size is known to be an incompletely dominant trait. Intercross the F1 and see if there is a range of sizes in the F2 (consistent with the incomplete dominance model) or if the F2 contains two size classes (consistent with the polygenic model). Intercross the F1 and see if the F2 contains three size classes (consistent with the incomplete dominance model) or if there is a range of sizes (consistent with the polygenic model). Intercross the F1 and see if there is a range of sizes in the F2 (consistent with the incomplete dominance model) or if the F2 contains only three size classes (consistent with the polygenic model).
c
Mendel's law of independent assortment states that chromosomes sort independently of each other during mitosis and meiosis. independent sorting of genes produces polyploid plants under some circumstances. each pair of alleles segregates independently of the other pairs of alleles during gamete formation. genes are sorted concurrently during gamete formation.
c
Sex-linked conditions are more common in men than in women because the genes associated with the sex-linked conditions are linked to the Y chromosome, which determines maleness. the sex chromosomes are more active in men than in women. men need to inherit only one copy of the recessive allele for the condition to be fully expressed. men acquire two copies of the defective gene during fertilization.
c
Suppose we have a pea plant with purple flowers, determined by the dominant allele P. How might you determine whether the plant is homozygous (PP) or heterozygous (Pp)? Cross the plant with a true-breeding purple plant. Examine the plant's chromosomes with a microscope. Perform a testcross: Cross the plant with a white one, which must be homozygous recessive (pp). Perform a testcross: Cross the plant with one with green seeds, which must be homozygous recessive (yy).
c
The alleles of a gene are found at ________ chromosomes. different loci on nonhomologous the same locus on nonhomologous the same locus on homologous different loci on homologous
c
The chromosome theory of inheritance is based upon which of the following sets of observations? Genes assort together; chromosomes come in pairs. Genes remain associated with one another; so do chromosomes. Genes segregate; chromosomes come in pairs. Genes occur as singular entities; chromosomes come in pairs.
c
Two identical twins are raised in different environments. They possess _____ genotypes and _____ phenotypes. contrasting ... identical identical ... dissimilar identical ... variable identical ... identical
c
Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as hybrids. monohybrid crosses. true-breeding. the F2 generation.
c
What is the normal complement of sex chromosomes in a human male? two X chromosomes and one Y chromosome one Y chromosome one X chromosome and one Y chromosome two Y chromosomes
c
Which of the following is an example of incomplete dominance in humans? ABO blood groups albinism hypercholesterolemia skin color
c
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? pleiotropy codominance polygenic inheritance incomplete dominance
c
Which plants in this figure must all be heterozygous? purple-flowered plants in the F2 generation purple-flowered plants in the P generation purple-flowered plants in the F1 generation white-flowered plants in the P generation
c
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? X−Z−Y Z−X−Y X−Y−Z Y−Z−X
c
Use the Punnett square from the introduction and the ones you drew for Part A to select the three statements that are true about the inheritance of this form of deafness. The child of a Dd father and Dd mother has a 50% chance of having hearing. If the first two children from Dd parents are deaf, there is no risk that their next child will also be deaf. If a deaf man and a hearing woman have a deaf child, the mother's genotype must be Dd. If a deaf child is born to hearing parents, both parents must be Dd. The child of a deaf man and a DD hearing woman will definitely have hearing.
c, d, e
A carrier of a genetic disorder who does not show symptoms is most likely to be ________ to transmit it to offspring. heterozygous for the trait and unable homozygous for the trait and able homozygous for the trait and unable heterozygous for the trait and able
d
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? The gene for color vision is incompletely dominant to the gene for sex determination. The gene for color vision is codominant with the gene for sex determination. The gene for color vision is found on the Y chromosome. The gene for color vision is found on the X chromosome.
d
According to this figure, heterozygotes for this form of hypercholesterolemia suffer from the disease because they According to this figure, heterozygotes for this form of hypercholesterolemia suffer from the disease because they produce an abnormally shaped LDL receptor. don't produce any LDL receptors. produce too many LDL receptors. don't produce enough LDL receptors.
d
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? 3 black-eyed:1 orange-eyed 1 black-eyed:3 orange-eyed 1 black-eyed:0 orange-eyed 0 black-eyed:1 orange-eyed
d
DdEe pea plants can produce _____ type(s) of gametes, but a ddee plant can produce _____ type(s) of gametes. two ... one one ... two four ... two four ... one
d
Female inheritance patterns cannot be analyzed by simply studying the X chromosome because the X chromosome is too large to analyze effectively. one X chromosome is deactivated in females. the X chromosome sometimes exchanges genetic information with the Y chromosome. the X chromosome is obtained from both father and mother.
d
For most sexually reproducing organisms, Mendel's laws For most sexually reproducing organisms, Mendel's laws can predict whether offspring will be male or female with 100% accuracy. explain the biological mechanisms behind why certain genes are dominant or recessive. help us understand the global geographic patterns of genetic disease. cannot strictly account for the patterns of inheritance of many traits.
d
Genes located close together on the same chromosomes are referred to as ________ genes and generally ________. codependent; do not sort independently during meiosis linked; sort independently during meiosis homologous; are inherited together linked; do not sort independently during meiosis
d
Hemophilia appears rarely in females. This is because _____. it only affects females with two X chromosomes the female must possess the hemophilia gene on one X chromosome it only affects males because they only have one X chromosome the female must possess the hemophilia gene on both X chromosomes
d
High levels of LDL cholesterol in the bloodstream can be the result of familial hypercholesterolemia, an inherited condition that displays incomplete dominance. In a family with a severely affected father and an unaffected mother, what percentage of their children are expected to have higher than normal blood cholesterol? High levels of LDL cholesterol in the bloodstream can be the result of familial hypercholesterolemia, an inherited condition that displays incomplete dominance. In a family with a severely affected father and an unaffected mother, what percentage of their children are expected to have higher than normal blood cholesterol? 0% 25% 50% 100%
d
How many sex chromosomes are in a human gamete? two three four one
d
If the two characteristics that Mendel looked at in his dihybrid cross of smooth yellow peas with wrinkled green peas had been controlled by genes that were located close together on the same chromosome, then the F2 generation _____. would have contained only individuals that were heterozygous for both genes would have contained four phenotypes in a 9:3:3:1 ratio would have contained no individuals that were heterozygous for both genes would have deviated from the 9:3:3:1 phenotypic ratio that is predicted by the law of independent assortment
d
Imagine that a deaf male has a child with a hearing female. You know that the male must have the genotype dd, but the female could be either Dd or DD. If the couple's first child has hearing, can you determine the mother's genotype? (Hint: Draw Punnett squares for the two possible crosses.) Her genotype must be DD. Her genotype must be Dd. Her genotype must be dd. Her genotype cannot be determined.
d
In people with sickle-cell disease, red blood cells break down, clump, and clog blood vessels. Blood vessels and broken cells accumulate in the spleen. Among other symptoms, this leads to physical weakness, heart failure, pain, and brain damage. Such a suite of symptoms can be explained by __________. a bacterial infection interacting with the sickle-cell allele side effects of the drugs used to treat sickle-cell disease the polygenic nature of sickle-cell disease the pleiotropic effects of the sickle-cell allele
d
Linked genes are inherited together. This is because linked genes _____. Linked genes are inherited together. This is because linked genes _____. govern traits that have nothing to do with one another have the same alleles residing on them govern traits (such as hair texture and hair color) that are functionally related are on the same chromosome
d
Mendel conducted his most memorable experiments on roses. guinea pigs. fruit flies. peas.
d
Most genetic disorders of humans are caused by a mutation that occurs in the egg, sperm, or zygote. dominant alleles. multiple alleles. recessive alleles.
d
Our understanding of the role played by genes in many human characteristics is advancing rapidly in, for example, body size, performance on IQ tests, and personality traits. In this new genetic era, the role of the environment __________. is important only in influencing personality traits is always far more important than genes in the development of complex human traits can largely be discounted in the development of complex human traits is to work with genes in complex and often unknown ways in the development of these traits
d
Previously, it was thought that the blending hypothesis explained inheritance. The blending hypothesis maintained that __________. mutation is the major source of new gene combinations many genes are lost in their transmission to offspring, but the remaining genes gradually reproduce the lost genes the characters governed by genes in the egg are different from the characters governed by genes in the sperm after a mating, genes of the two parents are mixed in the offspring and lose their individual identities
d
Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female fruit fly because the male chromosome is more susceptible to mutations. males are haploid. the male chromosome is more fragile than the female chromosome. the male's phenotype results entirely from his single X-linked gene.
d
Sickle-cell disease is an example of codominance and multiple alleles. multiple alleles and pleiotropy. multiple alleles, pleiotropy, and blended inheritance. codominance and pleiotropy.
d
Snapdragons show incomplete dominance in their flowers. A pink snapdragon is crossed with a red snapdragon. What color(s) are the offspring? 100% pink 100% red 50% red, 50% white 50% red, 50% pink
d
Sturtevant's genetic mapping _____. orders genes on a chromosome based on their location with respect to a stained band can be constructed only for sex chromosomes orders genes on a chromosome based on recombination frequencies
d
Tay-Sachs disease runs in Rebecca's family. On a family pedigree, she saw a shaded circle. This represented _____. a male carrier a male with Tay-Sachs a female carrier a female with Tay-Sachs
d
The Y chromosomes of mammals contain genes that code for _____. blood-clotting factor, among many other characters both eye pigment and blood-clotting factor, among many other characters eye pigment, among many other characters "maleness" and a few other characteristics
d
The cross-fertilization of two different, but true-breeding, varieties of pea plants will _____. yield the P generation be lethal produce an F2 generation result in hybrid plants
d
The crossover percentage between two different genes is _____. dependent on whether dominant or recessive alleles are carried by the two genes dependent on the sex of the parent greater as the distance between the two genes decreases greater as the distance between the two genes increases
d
The inheritance of height and weight can best be described as __________. being caused by microorganisms the results of a bad lifestyle Mendelian (dominant-recessive) inheritance polygenic and multifactorial
d
We can better understand our ancestry by analyzing the __________ in males. X chromosome gene for SRY gene for colorblindness Y chromosome
d
When applied to Mendel's experiments, the term true-breeding means a self-fertilization of two plants that produces _____. offspring with only dominant traits offspring with only recessive traits offspring with blended traits offspring identical to the parent
d
Which of the following statements best explains why dominant alleles that cause lethal disorders are less common than recessive alleles that cause lethal disorders? Unlike lethal disorders caused by recessive alleles, lethal disorders caused by dominant alleles usually cause the death of the embryo. The presence of a lethal dominant allele causes sterility. Lethal disorders caused by dominant alleles are usually more severe than lethal disorders caused by recessive alleles. 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.
d
Which of the following statements regarding genotypes and phenotypes is false? The genetic makeup of an organism constitutes its genotype. The expressed physical traits of an organism are called its phenotype. Alleles are alternate forms of a gene. An organism with two different alleles for a single trait is said to be homozygous for that trait.
d
Which of the following statements regarding hypotheses about inheritance is false? The theory of pangenesis incorrectly suggests that reproductive cells receive particles from somatic cells. The blending hypothesis does not explain how traits that disappear in one generation can reappear in later generations. Contrary to the theory of pangenesis, somatic cells do not influence eggs or sperm. The blending hypothesis suggests that all of the traits of the offspring come from either the mother or the father.
d
You conduct a dihybrid cross. A ________ ratio would make you suspect that the genes are linked. You conduct a dihybrid cross. A ________ ratio would make you suspect that the genes are linked. 3:1 9:3:3:1 1:1:1:1 12:1:1:4
d
Mendel worked _____. on the Human Genome Project with fruit flies on gene mapping on problems involving characters that were inherited together more often than expected by chance in a monastery
e