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Which of the following statements dogs is false?

all dogs are descended from wolves

Which of the following statements best represents the theory of pangenesis developed by hippocrates?

Partivces called pangenes, which originate in each part of an organism's body, collect in the sperm or eggs and a passed on to the next generation

Which of the following statements regarding hypotheses about inheritance is false?

the blending hypothesis suggests that all of the offspring come either the mother or the father

Mendel conducted his most memorable experiments on

peas.

Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as

Tru-breeding

Which of the following statements regarding cross-breeding and hybridization is false?

The hybrid offspring of a cross are the P1 generation

A monohybrid cross is

a breeding experiment in which the parental varieties differ in only one character

Which of the following statements regarding genotypes and phenotypes is false?

An allele that is fully expressed is referred to as a recessive

Research since Mendel's time has established that the law of the segregation of genes during gametes formation

Applies to all sexually reproducing organisms

All the offsprings of a cross between a black-eyed mendelien and an orange-eyed memdelien have black eyes. What's the expected pheontypic ratio of a cross between two oranges-eyed mendeliens?

0 black-eyed :1 orange -eyed

The alleles of a gene are found at _____chromosomes

The same locus on homologous

The phenotypic ration resulting from a dihybrid cross showing independent assortment is expected to be

9:3:3:1

Mendel's law of independent assortment states that

each pair of alleles segregates independently of the other pairs of alleles during gamete formation

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 alleles for color and vision segregate independently during gamete formation

A testcross is

a mating between an individual of unknown genotype and an individual heterozyous recessive for the trait of interest

Using a six sided die, what is the probability of rolling either a 5 or a 6?

1/6 +1/6 =1/3

Assumimg that the probability of having a female child is 50% and the probability of having a male cjild is also 50 what is the probability that a couple's first-born-child will be female and that their second child will be male?

25%

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 able

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 alleles at this locus, associated with normal hearing is D. Dr. Smith's parents could have which of the following genotypes?

Dd and Dd

Most genetic disorders of humans are caused by

recessive alleles

The vast majority of people afflicted with recessive disorders are born to parents who were

not affected at all by the disease

WHich of the following statements best explains why dominant alleles that cause lethal disorders are less common than recessive alleles that cause lethal disorders

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

Aminocentesis and chronic villus sampling allow for _____and_____ of the fetus so that it can be tested for abnormalities

Karyotyping ... Biochemical testing

Which of the following statements regaridng prenatal testing is false?

Chorionic viilus sampling is typically performed later in the pregnancy than amniocentesis

Which of the following statements regarding genetic testing is false?

Most human genetic diseases are treatable id caught early.

For most sexually reproducing organisms, Mendel's Lawa

Cannot strictly account for most patterns of inheritance.

Which of the following statements is false?

incomplete dominance supports the blending hypothesis

all the offspring of a cross between a red-flowered plant and a white -flowered plant have pink flowers. This means that the alleles for red flowers is_______to be the alleles for white flowers

incomplete dominance

Imagine that beak color is 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

incomplete dominance

Which of the following is an example of incomplete donminance in humans?

hypercholesterolemia

the expression of both alleles for a trait in a heterozygous individual illustrates

codominance

A person with AB blood illustrates the principle of

codominance

Which of the following statements regarding sickle-cell disease is false?

Sickle-cell disease causes white blood cells to be sickle-shaped

Sickle-cell disease is an example of

codominace and pleiotropy

Which of the following terms refers to a situation where a single phenotypic character is determined by the a effects of two or more genes?

polygenic inheritance

The individual features of all organisms are the result of

genetics and the environment.

The chromosome theory of inheritance states that

the behavior of chromosomes during meiosis and fertilization accounts for patterns of inheritance.

Genes located close together on the same chromosomes are referred to as___genes and generally___

liked....do not sort independently during meiosis

Linked genes generally

do not follow the laws of independent assortment

You conduct a dihybrid cross and then testcross the generation.A ___ratio would make you suspect that the genes are limked

7:7:1:1

Crossing over___genes into assortments of __not found in the parents

recombines linked ...alleles

The mechanism that "breaks" the linkage between linked genes is

crossing over

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?

What is the normal complement of sex chromosomes in a human male?

one X chromosome and one Y chromosome

The sex chromosome complement of a normal human male is

XY

How many sex chromosomes are in a human gamete?

one

How is sex determined in most ants and bees?

by the number of chromosomes

Given the sex determination system in bees, we can expect that

Females bees will produce eggs by meiosis, while male bees will produce sperm by mitosis

What is meant by the statement that "male bees are fatherless"?

Male bees develop from unfertilized eggs

Any gene located in a sex chromosome

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

the male's phenotype results entirely from single Xlinked gene.

A color blind woman marries a man who is not color blind. All of thier sons, nut none of their daughter, are color-blind. Which of the following statement correctly explains results?

The gene for color version is linked to the X chromosome

Sex-linked conditions are more common in men then in women because

Men need to inherit only one copy of the recessive allele for the condition to be fully expressed.

According to scientists, about what percentage of men currently living in Central Asia may be descended from Monogolian ruler Genghis Khan>

8%

Female inheritance patterns cannot be analyzed by simply studying the X chromosome because

the X Chromosomes is obtained from both father and mother

character

a heritable feature

trait

a distinguishing characteristic or quality

true-breeding

plants that produce offspring of the same variety when they self pollinate

hybridization

the mating, or crossing, of two varieties

P generation

The first set of parents crossed in which their genotype is the basis for predicting the genotype of their offspring, which in turn, may be crossed

F1 generation

the generation resulting immediately from a cross of the first set of parents

F2 generation

The second filial generation, which is comprised of offspring(s) resulting from a cross of the members of F1 generation.

alleles

alternate versions of a gene

dominant allele

in a heterozygote, the allele that is fully expressed in the phenotype

recessive allele

in a heterozygote, the allele that is completely masked in the phenotype

law of segregation

Mendel's fist law, stating that allele pairs separate during gamete formation, and then randomly reform as pairs during the fusion of gametes at fertilization

punnett square

a diagram used in the study of inheritance to show the results of random fertilization

homozygous

having two identical alleles for a certain trait

heterozygous

having two different alleles for a given genetic character

phenotype

the physical and physiological traits of an organism

genotype

the genetic makeup of an organism

testcross

breeding of an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. the ration of phenotypes in the offspring determines the unknown genotype

monohybrid

an organism that is heterozygous with respect to a singke gene of interest. results from a cross between parents homozygous for different alleles.

dihybrid

an organism that is heterzygous with respect to two genes of interest. results from a cross between parents double homozygous for different alleles

law of independent assortment

Mendel's second law stating that each allele pair segregates independently during gamete formation; applies when genes for two characteristics are located on different pairs of homologous chromosomes

incomplete dominance

a type of inheritance in which F1 hybrids have an appearance that is intermediate between the phenotypes of the parental varieties

complete dominance

a type of inheritance in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable

codominance

a phenotypic situation in which the two alleles affect the phenotype in separate, distinguishable ways

pleiotropy

the ability of a single gene to have multiple effects

epistasis

a phenomenon in which one gene alters the expression if another gene that is independently inherited

quantitative character

a heritable feature in a population that varies continuously as a result of environmental influences and the additive effect of two or more genes

polygenic inheritance

an additive effect of two or more gene loci on a single phenotypic character

norm of reaction

the range of phenotypic probabilities for a single genotype, as influenced by the environment

multifactorial

a type of phenotypic character influenced by the genetic and environmental factors

pedigree

a family tree describing the occurrence of heritable characters in parents and offspring across as many generations as possible

cystic fibrosis

a genetic disorder that occurs in people with two copies of a certain recessive allele; characterized by an excessive secretion of mucus and consequent vulnerability to infection; fatal if untreated

tay-sachs disease

a human genetic disease caused by a dysfunctional enzyme that fails to break down brain lipids of a certain class; seizures, blindness, and degeneration of motor and mental performance usually become manifest in a few months after birth

sickle-cell disease

a human genetic disease of red blood cells caused by the substitution of a single amino acid in the hemoglobin protein; it is the most common inherited disease among African Americans

huntington's disease

a human genetic disease caused by a dominant allele; characterized by uncontrollable body movements and the degeneration of the nervous system; usually fatal 10-20 years after the onset of symptoms

amniocentesis

a technique for determining genetic abnormalities in a fetus by the presence of certain chemicals or defective fetal cells in the amniotic fluid,obtained by aspiration from a needle inserted into the uterus

chorionic villus sampling (CVS)

a form of prenatal diagnosis to determine genetic abnormalities in the fetus. It entails getting a sample of the placental tissue and testing it.

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