Studied by 9 peopleIf a cell with genome of 20 pairs of chromosomes undergoes normal mitosis, how many cells result, and how many chromosomes are in each of the resulting cells?
A. Two cells, each with 20 chromosomes
B. Two cells, each with 40 chromosomes
C. Four cells, each with 10 chromosomes
D. Four cells, each with 20 chromosomes
E. Four cells, each with 40 chromosomes
B
If a cell with genome of 20 pairs of chromosomes undergoes normal meiosis, how many cells result, and how many chromosomes are in each of the resulting cells?
A. Two cells, each with 20 chromosomes
B. Two cells, each with 40 chromosomes
C. Four cells, each with 10 chromosomes
D. Four cells, each with 20 chromosomes
E. Four cells, each with 40 chromosomes
D
In cats, the allele for short hair (H) is dominant over the allele for long hair (h). A female cat shows the short hair trait, but in previous litters she produced some long-hair offspring. If this short-hair female is now mated with a long-hair male, what fraction of their offspring is expected to have long hair?
A. 0 (none)
B. 1/4
C. 1/2
D. 3/4
E.1 (all)
C
Sickle-cell anemia is inherited as a simple recessive traits. Heterozygote carriers do not have sickle-cell anemia. Neither John nor Maria have the disease sickle cell anemia, but since it occurs in their families they have been tested and know they both are heterozygous carriers of the recessive sickle-cell allele. Draw the Punnett square and answer:
What proportion of their offspring are expected to have sickle cell anemia?
A. 0 (none)
B. 1/4
C. 1/2
D. 3/4
E. 1 (all)
B
Sickle-cell anemia is inherited as a simple recessive traits. Heterozygote carriers do not have sickle-cell anemia. Neither John nor Maria have the disease sickle cell anemia, but since it occurs in their families they have been tested and know they both are heterozygous carriers of the recessive sickle-cell allele. \n Draw the Punnett square (same as Q4) and answer
What proportion of their offspring are expected to be heterozygous carriers of the sickle-cell trait?
A. 0 (none)
B. 1/4
C. 1/2
D. 3/4
E. 1 (all)
C
Flower color alleles in snapdragons show incomplete dominance. When red-flowering snapdragons are crossed with white-flowering snapdragons, all the offspring are heterozygous and have pink flowers. When two pink snapdragons are crossed, what proportion of their offspring would be expected to be pink?
A. 0 (none)
B. 0.25
C. 0.50
D. 0.75
E. 1.0 (all)
C
In a certain species, 2n = 60. If one diploid cell in this species undergoes meiosis, the products will be
A. 2 cells, each with 30 chromosomes
B. 2 cells, each with 60 chromosomes
C. 4 cells, each with 30 chromosomes
D. 4 cells, each with 60 chromosomes
C
Which of the following is true about the two members of a homologous pair of chromosomes?
A. they are identical DNA molecules
B. they form the two sides of one double helix
C. they separate from one another during meiosis II.
D. they contain the same gene loci in the same order
E. two of these are true.
D
For a certain mouse trait, allele D is dominant over allele d. A mouse with genotype DD is mated with a mouse with genotype dd. Of their offspring ___ are expected to show trait d, and ___ are expected to be heterozygous carriers of the d trait.
A. 50%, 50%
B. 0%, 50%
C. 0%, 100%
D. 50%, 100%
C
When a chestnut-colored horse is mated with a cream-colored horse, all the offspring are palomino (incomplete dominance). When two palomino horses are mated, what proportion of their offspring would be expected to be palomino?
A. 0 (none)
B. 0.25
C. 0.50
D. 0.75
E. 1.0 (all)
C
In mice, short hair trait is completely dominant, and long hair is a simple recessive trait. If a short-hair individual is mated with a long-hair individual and both long-hair and short-hair offspring result, then just from looking at the offspring you learn that:
A. the short-hair individual was homozygous
B. the short-hair individual was heterozygous
C. the long-hair individual was heterozygous.
D. more offspring are required in order to decide.
B
Which statement about an individual that is homozygous for a specific allele is NOT true?
A. Each of its body cells possesses two copies of that allele
B. Each of the gametes it produces contains one copy of that allele.
C. Both of its parents had to be homozygous for that allele.
D. It will pass that allele to all offspring.
C
Phenylketonuria (PKU) is a treatable metabolic disease inherited as a simple recessive trait. Jack and his wife Brittany do not have PKU, but both have a member of their extended family with PKU. When they have the genetic test, they both learn they are carriers of the PKU allele. (a) What is the probability their first child will be born with PKU, and then (b) what is the probability that if they have two children, both children will have PKU?
A. 1/2; 1/2
B. 1/2; 1/4
C. 1/2; 1/8
D. 1/4; 1/8
E. 1/4; 1/16
F. 1/8; 1/16
E
Classical albinism results from a particular recessive allele. Which of the following are the expected phenotypes of offspring from an albino woman and a normally pigmented man who has an albino father?
A. 3/4 normal 1/4 albino
B. 3/4 albino 1/4 normal
C. 1/2 normal 1/2 albino
D. all normal
E. all albino
C
A woman of blood type B marries a man with blood type A. Both of them have a parent with type O blood. From the information given, determine the genotypes of the couple, draw a Punnett square, and answer what blood types (phenotypes) are possible in their children?
A. Only blood types A or B
B. Blood types A or B or O
C. Blood types A or B or AB
D. Blood types A or B or AB or O
D
If an infant born to a mother with blood type O is also type O, possible types for the father are:
A. AB
B O or A
C. A or B
D. O only
E. O, A, or B
E
A woman with blood type A gave birth to a child with blood type AB. It is uncertain which of three men is the father of the child. Person X has blood type A, person Y has blood type O, and person Z, has blood type B.
Can one or more of these men (X, Y, Z) be eliminated as the father of the child based on ABO blood group data?
A. only Person X can be eliminated
B. only Person Y can be eliminated
C. only Person Z can be eliminated
D. Persons X and Y can be eliminated
E. Persons X and Z can be eliminated
F. Persons Y and Z can be eliminated
D
A woman is heterozygous for the recessive X-linked gene for hemophilia. Her husband is not affected by hemophilia. What are the parent genotypes (with X and Y chromosomes) Draw the Punnett Square for this mating. What proportion of their sons will have hemophilia?
A. 0 (none)
B. 1/4
C. 1/2
D 3/4
E. 1 (all)
C
Very few protein-coding genes are on the Y chromosomes. Y-linked genes include the sry gene that expresses the testis-differentiation protein. A male with this gene will
A. usually pass it to his sons, but about 10% of the time also to a daughter
B. only pass the gene to his sons
C. only pass the gene to his daughters
D. only pass the gene to his grandsons, not sons
E. pass the gene to all of his children if the mother is a carrier.
B
Identical twin girls (same genotype) could express an X-linked trait differently in different cells if
A. they experienced different new mutations in their X chromosomes
B. the trait was sometimes dominant and sometimes recessive
C. the cells had different X chromosomes inactivated
D. some cells were homozygous and others heterozygous for the trait
C
Hemochromatosis is an inherited disease caused by a recessive allele (not sex-linked). If a woman and her husband, who are both heterozygous carriers, have three children, what is the probability that all three children are of normal phenotype (do not have hemochromatosis).
A. 0
B. 1/16
C. 1/4
D. 27/64
E. 3/4
F. 1
D
In the Hardy-Weinberg equations, which term gives the recessive allele frequency? [notation: ^2 = squared]
A. p
B. q
C. 2pq
D. p^2
E. q^2
B
In the Hardy-Weinberg equations, which of these three terms gives the homozygous recessive genotype frequency? [notation: ^2 = squared]
A. q
B. 2pq
C. q^2
C
A gene in humans has two alleles, M and N, that are co-dominant and code for slightly different red blood cell surface proteins. If the frequency of allele M is 0.2, according to the Hardy-Weinberg equation, the frequency of the genotype MN in the population should be what?
A. 0.16
B. 0.20
C. 0.32
D. 0.40
E. 0.80
C
[from text, ch 21] A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2? \n
A. 0.70
B. 0.49
C. 0.42
D. 0.21
C
In a population of mice in Hardy-Weinberg equilibrium, 4% (= 0.04) of individuals are albino (show the recessive a trait); the rest show the dominant agouti (A). What is the frequency of agouti A allele?
A. 0.04
B. 0.20
C. 0.40
D. 0.80
E. 0.96
D
In a population of fish, the frequency of the dominant allele A at a locus is 0.8. If the population has 500 individuals, what is the expected number of A alleles in the gene pool? [Think first – how many total alleles are in this gene pool?]
A. 320
B. 400
C. 480
D. 640
E. 800
E
In a beetle population in Hardy-Weinberg equilibrium there is a gene locus with a dominant allele B and a recessive allele b. 84% of the individuals in the population show the dominant trait in their phenotype (complete dominance, not sex-linked). In a sample of 100 individuals from this population, about how many individuals would be homozygous for the dominant allele? [Think first- what percent of individuals show the recessive trait in their phenotype? What is their genotype?]
A. 16
B. 25
C. 36
D. 50
E. 84
C
The ultimate (original) origin of genetic variation is
A. genetic drift
B. natural selection
C. mutation
D. founder effect
E. non-random mating
C
If the frequency of alleles in a gene pool is 90% A and 10% a, what is the frequency of individuals with the genotype AA?
A. 0.90
B. 0.81
C. 0.50
D. 0.09
E. 0.01
B
Black fur in mice (B) is dominant to brown fur (b). In a population of 100 mice, the frequency of the dominant allele is 0.6. How many mice in the population, randomly picked, are expected to have brown fur?
A. 16
B. 36
C. 40
D. 48
E. 50
A
A small group of birds left their original large mainland population and started a new population isolated on an island. Several generations later, a particular color pattern is much more common in the island birds than in the mainland population, most likely due to which?
A. the founder effect
B. heterozygote advantage
C. mutation
D. nonrandom mating
E. gene flow
A
There is a large population of organisms. Ten females and two males wander off and join another large population. This is an example of:
A. gene flow
B. genetic drift
C. sexual selection
D. artificial selection
E. non-random mating
A
The ultimate origin of genetic variation is:
A. genetic drift
B. random mutation
C. natural selection
D. a founder effect
E. non-random mating
B
Which one of the following conditions would PREVENT the opportunity for evolution by natural selection? That is, under this condition, evolution by natural selection could not occur.
A. All members of the population are genetically identical
B. The environment often changes conditions.
C. Some individuals have a much higher reproductive fitness than others
A
Natural selection changes allele frequencies because some ___ survive and reproduce better than others. [from text end of chapter 21]
A. alleles
B. gene loci
C. species
D. individuals
D
Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating which of these? [from text end of chapter 21]
A. the bottleneck effect
B. disruptive selection
C. frequency-dependent selection
D. stabilizing selection
D
Evolution is best defined as which of the following?
A. a change in population size for a species
B. a change in living conditions for an organism
C. a change in genetic composition of a population from one day to the next day
D. a change in genetic composition of a population from generation to generation
D
What are adaptations?
A. inherited characteristics of organisms that enhance their survival and reproduction in specific environments
B. acquired characteristics of organisms that enhance their survival and reproduction in specific environments
C. processes that allow individuals with certain inherited traits to survive and reproduce
D. patterns seen in fossils documenting the origins of other new groups of organisms
A
In areas of Africa in which malaria is prevalent, many human populations exist in which the allele that produces sickle-cell disease and the allele for normal red blood cells occur at constant frequencies, despite the fact that sickle-cell anemia disease frequently causes death at an early age. This is an example of
A. the founder effect
B. heterozygote advantage
C. mutation
D. nonrandom mating
E. gene flow
B
Which form of speciation always involves a geographic barrier that initially separates two subsets of a single population?
A. allopatric
B. sympatric
C. reduced hybrid fertility
D. habitat isolation.
A
A genetic analysis of a certain species found that all individuals were homozygous at many gene loci, even for genes that were not at all important to survival, so any variation there would have been neutral (zero selection). The most likely explanation is a history of
A. large population size
B. high rates of mutation
C. genetic bottleneck
D. extensive gene flow with other populations
C
In evolution, which driving factor most consistently requires a small population as a precondition for its occurrence?
A. mutation
B. nonrandom mating
C. genetic drift
D. natural selection
C
Which is true of natural selection?
A. Natural selection is a random process
B. Natural selection creates beneficial mutations
C. The only way to eliminate harmful mutations is through natural selection.
D. Mutations occur at random; natural selection can preserve and distribute beneficial mutations
D
Which of the following is most likely to produce an African butterfly species in the wild whose members all have one common color pattern?
A. artificial selection
B. directional selection
C. sexual selection
D. disruptive selection
B
Which of the following is LEAST likely to help maintain genetic variation in a population over time?
A. Directional selection
B. Heterozygote advantage
C. Varying environments
D. Sexual recombination
A
According to the biological species definition, two populations of individuals are considered members of the same species if they
A. resemble each other in color patterns
B. can potentially interbreed
C. overlap in their geographic range and habitat
D. share the same morphological traits
B
Species-specific courtship behaviors serve as which type of reproductive isolating mechanism?
A. habitat isolation
B. behavioral isolation
C. mechanical isolation
D. gametic isolation
B
Which mechanism would reverse or stop the process of speciation?
A. increased gene flow
B. gene pools of the two species becoming increasingly different
C. increased ability of females to discriminate mates
D. decreased production of hybrids
A
Note
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