Deck 11: The Eukaryotic Chromosome

Question 1

Microevolution is defined as

A) a process that includes new species formation.
B) changes in the frequency of alleles within a population.
C) evolution of microorganisms.
D) interactions between species.
E) All of the choices are correct.

Answer 1

B

Question 2

Population genetics provides answers for all of the following questions except which one?

A) What is the frequency of genetic disease in a population?
B) What fraction of the phenotypic variation in a trait is the result of genetic variation?
C) What alleles are most likely to mutate?
D) Given certain quantifiable variables,how long is a disease likely to persist?
E) How rapidly can a disease gain a foothold in a population?

Answer 2

C

Question 3

The genotypic frequency of inheriting autosomal recessive condition phenylketonuria is 1 in 3,600 people.The frequency of the normal allele is

A) 0.0167.
B) 0.9833.
C) 0.0328.
D) 0.00286.
E) 3,599.

Answer 3

B

Question 4

In humans,brachydactyly is a dominant condition;6,400 people in a population of 10,000 show the disease (1,600 are BB,4,800 are Bb)and 3,600 are normal phenotypes (bb).The frequency of the b allele is

A) 0.6.
B) 0.4.
C) 0.36.
D) 0.48.
E) 0.16.

Question 5

Which of the following is true of fitness?

A) it is defined by an individual's ability to reproduce.
B) it is defined by changes in population size.
C) it always increases over time.
D) it always decreases over time.
E) it always the same for a given genotype.

Question 6

The frequency of the Hemoglobin A allele is 0.9.The heterozygote with the recessive allele,s,shows resistance to the malarial parasite.What is the frequency of the heterozygote for the pair As?

A) 0.81
B) 0.1
C) 0.01
D) 0.18
E) 0.09

Question 7

The proportion of individuals in a population that are of a particular genotype is the

A) phenotype frequency.
B) genotype frequency.
C) allele frequency.
D) population frequency.
E) gametic frequency.

Question 8

A disease that has been studied in great detail for heterozygote advantage is

A) brachydactyly.
B) sickle-cell disease.
C) insulin-dependent diabetes.
D) albinism.
E) tuberculosis.

Question 9

Unpredictable,chance fluctuation in allele frequency that has a neutral effect on fitness is called

A) founder effect.
B) selection.
C) genetic drift.
D) mutation.
E) inbreeding.

Question 10

The process in which rare alleles increase in frequency in a new population is known as

A) gene flow.
B) genetic drift.
C) founder effect.
D) inbreeding.
E) selection.

Question 11

Which of the following is not one of the assumptions of the Hardy-Weinberg law?

A) The population is very large.
B) Non-random mating occurs within the population.
C) Mutations in the alleles do not occur.
D) No migration occurs into or out of the population.
E) The ability of all genotypes for survival and reproduction is the same.

Question 12

The proportion of individuals in a population that are of a particular phenotype is the

A) phenotype frequency.
B) genotype frequency.
C) allele frequency.
D) population frequency.
E) gametic frequency.

Question 13

If a population exhibits a relative fitness of the wild-type (AA)genotype of 0.8,and that of the heterozygote (Aa)of 1.0,then the relative advantage in fitness of the heterozygotes would be

A) 0.8.
B) 0.08.
C) 0.16.
D) 0.28.
E) 1.25.

Question 14

Which of the following is not true of individuals within a population?

A) they can interbreed.
B) they reside in the same area.
C) they inhabit the same space at the same time.
D) they are all of the same species.
E) they all have the same genotype.

Question 15

The sum total of all alleles carried in all members of a population is called its

A) gene pool.
B) genome.
C) ploidy.
D) polygenic sum.
E) polymorphism.

Question 16

Frequency of disease alleles is influenced by

A) heterozygote advantage.
B) mutation.
C) time of onset of disease.
D) selection.
E) All of the choices are correct.

Question 17

The heterozygote genotype frequency term for a gene with two alternate alleles A (frequency p)and a (frequency q)in the Hardy-Weinberg equation is

A) p².
B) q².
C) 2pq.
D) (p + q)².
E) p + q.

Question 18

Hardy-Weinberg equilibrium in populations is defined as conditions that produce

A) only heterozygotes.
B) many lethal alleles.
C) genetic drift.
D) unchanging allele frequencies from generation to generation.
E) purifying selection.

Question 19

Many human recessive genetic diseases are maintained despite continuing selection against them because

A) heterozygotes have a higher fitness than either homozygote.
B) the recessive alleles mutate to dominant type.
C) there is no inheritance for the recessive allele.
D) the dominant allele frequency remains the same over generations.
E) None of the choices are correct.

Question 20

Which of the following conditions is generally not true about natural populations?

A) Size is not always very large.
B) Individuals do not mate at random.
C) New mutations do occur.
D) There is migration in and out of the population.
E) Different genotypes have the same fitness.

Question 21

A number of interacting genes produce quantitative inheritance.The transmission of these genes can be seen in the phenotypical pattern of

A) discontinuous distribution of discrete phenotypes.
B) continuous variation in phenotypic expression.
C) strict dominance and recessiveness.
D) a small number of discrete phenotypic classes.
E) only discontinuous distribution of discrete phenotypes and continuous variation in phenotypic expression.

Question 22

The total phenotype variance (V_P)is

A) the sum of genetic variance (V_G)and environmental variance (V_E).
B) the difference between V_G and V_E.
C) not dependent on V_G.
D) not dependent on V_E.
E) always constant.

Question 23

Continuous traits are

A) due to sex-linked genes only.
B) due to autosomal genes only.
C) qualitative in nature.
D) quantifiable in measurements.
E) the result of test-crosses only.

Question 24

Diseases persist because

A) diseased individuals are not prevented from reproducing.
B) mutation balances selection.
C) the alleles become dominant.
D) diseases do not affect fitness.
E) only a small fraction of the population is ever diseased.

Question 25

Brown insects living in a dark background survived in a ratio of 90/120,while the same insects in a lighter background survived in a ratio of 30/120.The ratio of relative fitness of the insects in dark backgrounds to lighter backgrounds is given as

A) 1 : 0.333.
B) 0.40 : 0.60.
C) 90 : 120.
D) 1 : 0.
E) 0.60 : 0.40.

Question 26

The response to selection,R,is equal to

A) the heritability (h²)of a trait.
B) the strength (S)of selection.
C) the difference between h² and S.
D) S/h².
E) h²S.

Question 27

When a trait has a large heritability,it is primarily genetically determined,and thus it is not affected by the environment.

Question 28

If the relative fitness of genotypes MM,MN,and NN are 0.8,1.0,and 0.2 respectively,the expected equilibrium frequency of N is

A) 0.8
B) 1.0
C) 0.2
D) 1.25
E) 4.0

Question 29

Multifactorial inheritance is observed in phenotypes that show typically

A) only one discrete type.
B) two extremes.
C) continuous variation.
D) a higher mutation rate.
E) All of the choices are correct.

Question 30

The loss of allelic variation due to an event that decreases the size of the entire population is called

A) gene flow.
B) genetic drift.
C) founder effect.
D) population bottleneck.
E) selection.

Question 31

The total genetic relatedness of two siblings is

A) 2.0
B) 1.0
C) 0.5
D) 0.2
E) None of the choices are correct.

Question 32

What is the role of neutral genetic drift in future evolution of humans?

A) Significant,due to increased migration.
B) Significant,due to decreased mutation from environmental toxins.
C) Almost none,due to increased migration.
D) Almost none,due to assortative mating.
E) Almost none,because of the large population size.

Question 33

Which of the following is not true about monozygotic twins?

A) They share all alleles at all loci.
B) They have a genetic relatedness of 0.5.
C) They have a genetic relatedness of 1.0.
D) They come from the joining of a single egg with a single sperm cell.
E) They are the result of a split of the zygote after fertilization.

Question 34

Twins from two individual zygotes (dizygotic twins)

A) are related genetically the same as monozygotic twins.
B) share 0% genetic similarities.
C) are similar in 100% of genetic sequences.
D) are related genetically the same as non-twin siblings.
E) are similar to the parents.

Question 35

Multifactorial traits

A) are affected by both genetic and environmental factors.
B) are continuous.
C) vary over a continuous range of measurements.
D) are affected by environmental factors such as penetrance and expressivity.
E) All of the choices are correct.

Question 36

Which of the following is true of a trait with high narrow-sense heritability?

A) it is resistant to natural selection but not artificial selection
B) it has high epistatic variation
C) it has high dominance variation
D) it has large potential for evolution via selection
E) it is resistant to artificial selection but not natural selection

Question 37

Which of the following does not contribute to the antibiotic resistance of bacterial pathogens?

A) Patient's noncompliance with drug treatments.
B) Strong selection imposed by antibiotic increases the rate of evolution in each generation.
C) Plasmids provide a means for the genetic exchange of resistance genes.
D) Antibiotic treatment is stopped prematurely.
E) Hardy-Weinberg equilibrium.

Question 38

A cross between a tall and a short bean plant produced intermediate height in the F₁ generation.When the F₁ plants were crossed with plants of the original parental heights,plants with a range of heights in between the extremes were produced.The mode of inheritance is described as

A) multifactorial.
B) independent assortment.
C) incomplete dominance.
D) codominance.
E) segregation.

Question 39

The frequencies of ABO blood groups in a certain population are: A = 0.22,B = 0.44,AB = 0.18,and O = 0.16.The frequency of the O allele in the population is

A) 0.469
B) 0.663
C) 0.424
D) 1.0
E) 0.4

Question 40

Heritability is defined as

A) V_G.
B) V_P.
C) V_E.
D) V_G/V_P.
E) V_P/V_G.

Question 41

Complex traits that are multifactorial are continuous.They are also called quantitative traits because they vary over a continuous range of measurement.

Question 42

Genetic drift has a predictable effect on evolution that scientists can easily calculate.

Question 43

Derivation of the Hardy-Weinberg law depend on five assumptions regarding the nature of the population in question,including that there is no migration into or out of the population.

Question 44

The evolution of drug resistance in bacteria results from several factors,including short generation time;large populations,which ensure incidence of mutations;strong selection by drugs;and the variety of ways by which bacteria can acquire new genetic diversity.

Question 45

Fitness is the term that population geneticists use to describe an individual's relative ability to survive and transmit genes to the next generation.

Question 46

How does the founder effect dictate the genetic composition of the new population?

Question 47

Heterozygous advantage is sometimes responsible for the retention of recessive genes that would otherwise reduce fitness.

Question 48

What is migration? How does it affect Hardy-Weinberg equilibrium?

Question 49

The definition of allele frequency is proportion of gene copies in a whole population that are of a specific allele type;the total number of gene copies is equal to two times the number of individuals in the population.

Question 50

Heritability is the proportion of total phenotypic variance due to genetic variance.

Question 51

One way scientists attempt to control confounding factors due to environmental variability is through cross-fostering.

Question 52

State the relationship of genetic variance (V_G)and phenotypic variance (V_P)to heritability.

Question 53

The founder effect may lead to a higher incidence of certain alleles than seen in large diverse populations.

Question 54

What are the components of phenotypic variance?

Question 55

The binomial Hardy-Weinberg equation is represented by p² + p²q² + q² = 1.

Question 56

A population that achieves genotype frequencies of p²,2pq,and q² in just one generation and remains at these frequencies is said to be in Hardy-Weinberg equilibrium.

Question 57

Selection for resistance in the presence of pesticides is the only factor that influences the rate of resistance among pest populations.

Question 58

Explain why a population carries more genetic diversity than does an individual.

Question 59

What is selection? How does it alter allele frequencies?

Question 60

What is genetic drift? Is it dependent on the size of the population?

Question 61

What is the difference between natural and artificial selection?

Question 62

What is the difference between phenotype frequency,genotype frequency,and allele frequency?

Question 63

You have discovered a small population of a unique vole species in a single high-mountain valley.Humans decimated the population outside this valley in the last centuries to use their fur in slippers.A genotypic analysis of the remaining voles shows a high incidence of recessive lethal alleles at three loci.You have been given a grant to begin a captive breeding program with a subset of the population,in hopes that more voles can be produced and released into the wild.Explain your strategies for this project.

Question 64

List five forces that change the frequency of an allele in a population and discuss why the elimination of a deleterious recessive allele is nearly impossible.

Question 65

Derivation of the Hardy-Weinberg law depends on what five assumptions?

Question 66

How can a value of 1.0 for H² be interpreted?

Question 67

Define a population.

Question 68

How would studies on monozygotic and dizygotic twins help in the understanding of the genetic basis of behavior in humans?