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75 Cards in this Set

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A couple who are both carriers for the gene for cystic fibrosis have two children who have cystic fibrosis. What is the probability that their next child will have cystic fibrsosis?
25
A couple who are both carriers for the gene for cystic fibrosis have two children who have cystic fibrosis. What is the probability that their next child will be phenotypicall normal?
75
What is a genetic cross called between an individual of unknown genotype and a homozygous recessive?
a test cross
In cross a homozygous recessive with a heterozygote, what is the chance of getting an offspring with the homozyous recessive phenotype?
50
In snapdragons, heterozygotes have pink flowers, whereas two homozygotes have red flowers or white flowers. When plants with red flowers and are crossed with plants with white flowers, what proportion of the offspring will have pink flowers?
100
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) is dominant to long tails (t). What proportion of the progeny of the cross BbTt x BBtt will ahve black fur and long tails?
8/16
What was the most significant conclusion that Gregor Mendel drem from his research?
Traits are inherited in discrete units, one from each parent.
A couple has three children, all of whom have brown eyes and blond hair. Both parents are homozygous for brown eyes (BB), but one is a blond (rr) and the other is a redhead (Rr). What is the probability that their next child will be a brown-eyed redhead?
1/2
A woman and her husband both show the normal phenotype for pigmentation, but both had on eparent who was an albino. Albinism is an autosomal recessive trait. What is the probability that their first child will be an albino?
25
A woman and her husband both show the normal phenotype for pigmentation, but both had on eparent who was an albino. Albinism is an autosomal recessive trait. If their first two children have normal pigmentation, what is the chance that their third whild will be an albio?
25
A woman and her husband both show the normal phenotype for pigmentation, but both had on eparent who was an albino. Albinism is an autosomal recessive trait. What is the chance that their fourth child will have a homozygous genotype?
50
The fact that all seven of the garden pea traits studied by Mendel obeyed the principle of independent assortment meants that the
seven pairs of alleles determining these traits behave as if they are on different chromosomes.
The ability of a gene to have multiple phenotype effects
pleiotropy
One example is the ABO blood group system.
multiple alleles
The phenotype of the heterozygote differs from the phenotype of both homozygotes.
incomplete dominance
The probability that four coins will come up heads when flipped simultaneously is
1/16
Effects of this recessive single gene can be completely overcome by regulating the diet of the affected individual.
phenylketonuria
This is caused by a dominant single gene defect that generally does not appear until the individual is 30-40 years of age.
Huntington's disease
Individuals with this disorder are unable to metabolize gangliosides, which affects proper brain development. Affected individuals die in early infancy.
Tay-Sachs disease
Substitution of the "wrong" amino acid in the hemoglobin protein results in this disorder.
sickle-cell disease
Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. A man and woman, both normally pigmented, have an albino child together. For this trait, what is the genotype of the albino child?
homozygous recessive
Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. A man and woman, both normally pigmented, have an albino child together. The couple decides to have a second child. What is the probability that the child will be albino?
1/4
Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. A man and woman, both normally pigmented, have an albino child together. The mother is now pregnant for a third time, and her doctor tells her she is carrying fraternal twins. What is the probability that both children will have normal pigmentation?
9/16
Recipes are instructions on how to prepare food, just like genes are instructions the cell uses to make proteins. Using this analogy, a cookbook is analogous to
a chromosome
Remember how you used to make up teams in gym class? The class would line up and count off by twos. All the students who were "ones" would be on one team and the "twos" would be the other team. This is analogous to Mendel's concept of
segregation
When does a synaptomeal complex form?
during prophase I of meiosis
The phases of meiosis that cause the most variation in the four resulting daughter cells are
prophase I and anaphase I
If the liver cells of an animal have 24 chromosomes, the sperm cells would have how many chromosomes?
12
Which of the following events occurs during prophase I of meiosis?
synapsis and crossing over
Which of the following is true of a species that has a chromosome number of 2n = 16
A gamete from this species has 8 chromosomes
At which stage of mitosis are chromosomes photographed in the preparation of a karyotype?
metaphase
Which of the following is FALSE in comparing prophase I of meiosis and prophase of mitosis?
Tetrads form in both
In a given organism, how do cells at the completion of meiosis compare with cells that are just about to begin meiosis?
They have half the number of chromosomes and 1/4th the amount of DNA.
What is a karyotype?
a method of organizing the homologous chromosomes of a cell in relation to their number, size, and type
Which diagram represents late prophase I of meiosis?
B or IV
At the completion of which stage will chromosomes have the least amount of DNA per nucleus?
E or V
Crossing over occurs during which phase od meiosis?
prophase I
Tetrads of chromosomes are aligned at the center of the cell; independent assortment soon follows.
E or II
Synapsis of homologous pairs occurs; crossing over may occur.
B or I
Nuclear envelopes may form; no replication of chromosomes takes place.
D or V
Centromeres of sister chromatids uncouple and chromatids separate.
D or VIII
Which of the life cycles is typical for animals?
D or I only
Which of the life cycles is typical for plants and some algae?
E or I and III
Which of the life cycles is typical for many funti and some protists?
D or II only
Which life cycle would generate the greatest genetic diversity and why?
They would all generate equivalent genetic diversity.
The word homologous literally means same location. How does this relate to homologous chromosomes?
Both B and C are correct (B: The bands resulting from staining are found in the same location, C: The chromosomes have the same genes in the same location.)
Which of the following terms belongs with the words synapsis, tetrads, and chiasmata?
Crossing over
In animals, meosis results in gametes, and fertilization results in
zygotes
The X and the Y chromosomes are called sex chromosomes beacuse
genes located on the chromosomes play a role in determining the sex of the individual.
In animals, somatic cells result from mitosis and ______ result from meiosis.
gametes
In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A lethal recessive allele that causes death of the embyro occurs on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male heterozygous for the letal allele and a normal female?
2:1 male fo female
Which of the folowing statements is TRUE regarding genomic imprinting?
It explains cases where the gender of the parent from whom al allele is inherited affects the expression of that allele.
If inheritance of a human trait is sex-linked (on the X chromosome) and recessive, any of the following could result EXCEPT that
the trait could be more common in females than males
The following is a list of chromosomal alterations. Which one of these would automatically cause two of the others?
nonreciprocal translocation
What does independent assortment refer to?
the separation of allels in anaphase I
A Barr body is normally found in the nuclues of which kind of human cell?
somatic cells of a female only
The particular position of a gene on a chromosome is known as a(n)
locus
The frequency of crossing over between any two linked genes is
proportional to the distance between them
A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color-blind marries a color-blind male. What is the probability that this couple's son will be color-blind?
50
A man who carries an X-linked allele will pass it on to
all of his daughters
An achondroplastic dwarf man with normal vision marries a color-blind woman of normal neight. The man's father was six feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. How many of ther female children might be expected to be color-blinded dwarfs?
none
An achondroplastic dwarf man with normal vision marries a color-blind woman of normal neight. The man's father was six feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. How many of ther male children would be color-blind and normal height?
half
An achondroplastic dwarf man with normal vision marries a color-blind woman of normal neight. The man's father was six feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. They have a daughter who is a dwarf with normal color vision. What is the probability that she is heterozygous for both genes?
1.00
What is the genotype of individual III-2?
E or cY
What is the genotype of individual I-2?
B or Cc
In the pedigree in Figure 15.1, what is the probability that individual III-1 is heterozygous?
A or .50
In the pedigree in Figure 15.1, what is the probability that individual III-3 is homozygous?
A or 0
Individual III-1 could be homozygous or heterozygous. When she has children, which of the following possible fathers would be most informative of her genotype?
a color-blind man
In this pedigree, several of the characteristics of sex-linked recessive traits are apparent. Which one is NOT demonstrated in this pedigreeg?
The occurence of the trait skips generations.
There is good evidence for linkage when
genes do not segregate independently during meiosis
The sequence of genes on the chromosome of a certain common fly is THMORGAN. You find a population of this fly at the top of a mountain. When you cross it with normal flies, the number of offspring is reduced. In studying its chromosomes, you find that it has a sequence of genes of TGMOHAN. Which of the following best explains this?
two inverstions occured
The sequence of genes on the chromosome of a certain common fly is THMORGAN. You find a population of this fly at the top of a mountain. When you cross it with normal flies, the number of offspring is reduced. In studying its chromosomes, you find that it has a sequence of genes of TGMOHAN. You find a second population that you believe is intermediate between the two. What should its sequence of genes be?
Either B or C (B: TGROMHAN, C: THROMAGAN)
A cassetee tape or compact disk contains a series of distinct pieces of electrical or physical information that are interpreted by a tape player or compact disk player, resulting in music. If the information that produces a song is analogous to a gene, and the tape or compact disk is analogous to a chromosome, then the linkage of genes is analogous to
the sequence of songs on the tape or disk
The following is a map of four genes on a chromosome:
B or (A and G)
In the following list, which term is LEAST related to the others?
triploid