Mastering bio exam 2

What did researchers discover about the genetic mutation causing lactase persistence? A. The mutation affects different genes in European and African populations. B. It is found in a regulatory region (a "switch") upstream of the lactase gene. C. It is found in the coding region of the lactase gene on chromosome 2. D. It is the same mutation in European and African populations.

B

When should a lactase supplement be taken in order to be most effective, and why? A. taking it anytime is effective, because lactase works while in the bloodstream B. at the same time the dairy product is consumed, so that the lactase will be in contact with the lactose C. after the dairy product is consumed, since it takes a while for the lactase to start working D. before the diary product is consumed, so the lactase has time to spread in the small intestine

B

Which assumption must be met for a population to be in Hardy-Weinberg equilibrium for a specific gene? A. Mating must be nonrandom with respect to the gene. B. No genetic drift can affect allele frequencies for the gene. C. The number of immigrants must equal the number of organisms emigrating. D. Natural selection must favor one phenotype.

B

Which discovery supports the hypothesis that evolution of the lactase-persistence trait was driven by the use of milk in pastoralist cultures? A. The lactase gene is present in both humans and domesticated animals. B. Ancient pots used to hold milk are about the same age as the lactase-persistence mutations. C. People who are lactase persistent have a mutation in the switch region of the lactase gene. D. Scientists have discovered different mutations for lactase persistence in different cultures.

B

If a person has two normal copies of the hemoglobin allele, which statements are true? Select all that apply. A. The person is heterozygous at the hemoglobin locus. B. The person is homozygous at the hemoglobin locus. C. The person is protected against malaria. D. The person is susceptible to malaria.

B and D

A particular diploid plant species has 48 chromosomes, or two sets. A mutation occurs and gametes with 48 chromosomes are produced. If self-fertilization occurs, the zygote will have _____ set(s) of chromosomes. A. 1 B. 2 C. 3 D. 4 E. 5

D

Genes contain the information for making what classes of proteins? A. Enzymes B. Structural proteins C. Membrane proteins D. All proteins

D

In 1949, Dr. Tony Allison observed a high frequency of Kenyans carrying the sickle cell allele in coastal areas and near Lake Victoria, but a lower frequency in the highlands. What did he hypothesize? A. He hypothesized that malaria is a genetic disease. B. He hypothesized that malaria causes sickle cell disease. C. He hypothesized that sickle cell disease was an environmental, not a genetic disease. D. He hypothesized that there was a connection between malaria and sickle cell disease.

D

Mutant tetraploid plants _____. A. are usually sickly B. are able to interbreed with their parents C. have an odd number of chromosomes D. are unable to interbreed with a diploid plant E. are unable to self-fertilize

D

Compare sickle cell disease and malaria. A. Sickle cell disease and malaria are both potentially lethal diseases. B. Sickle cell disease and malaria are both genetic diseases. C. Sickle cell disease and malaria are both infectious diseases. D. Sickle cell disease and malaria are both inherited diseases.

A

How do autopolyploidy and allopolyploidy differ? A. The chromosomes of an autopolyploid individual come from the same species, while an allopolyploid individual has sets of chromosomes from different species. B. Autopolyploidy is a mechanism of speciation in plants, while allopolyploidy is a mechanism of speciation in animals. C. Autopolyploidy is sympatric, while allopolyploidy is allopatric. D. Only autopolyploidy involves an increase in chromosome sets.

A

Humans are diploid and have 46 chromosomes (or two sets). How many sets of chromosomes are found in each human gamete? A. 1 B. 2 C. 3 D. 4 E. 5

A

Predict what will happen to the frequency of the sickle cell allele in areas where malaria has been eradicated. A. The sickle cell allele will increase in frequency. B. The sickle cell allele will decrease in frequency. C. The sickle cell allele frequency will not be affected.

B

In some populations, 1 in 500 people have sickle cell disease. What reason does the film give for why a potentially deadly, inherited disease is found at such high frequencies? A. Individuals with one sickle cell allele are protected from malaria and do not have sickle cell disease, thus keeping the allele in the population. B. Sickle cell alleles are new mutations and not enough time has gone by for these alleles to be eliminated from the population by natural selection. C. Individuals with two sickle cell alleles have an evolutionary advantage because they do not get sickle cell disease or get infected with malaria. D. Individuals with two normal hemoglobin alleles get both sickle cell disease and are susceptible to malaria, so these alleles are eliminated from the population.

A

Suppose that a mutation for lactase-persistence occurred in each of the populations described below. In which populations would the mutation be more likely to increase in frequency over time because of natural selection? A. a population that raises wheat and sheep B. a population that raises rice and tilapia fish C. a population that raises potatoes and chickens D. a population that raises corn and beans

A

What is a gene pool? A. a hypothetical collection of all the possible alleles in a population B. a puddle of water that contains gametes in it C. a collection of all the genes that occur in an individual D. a hypothetical collection of all the genes that occur in a habitat

A

Which is the first step in allopatric speciation? A. Physical isolation of two populations B. Loss of genetic variation due to genetic drift C. Differential natural selection in different environments D. Genetic divergence due to mutation

A

Which mechanism of reproductive isolation causes postzygotic isolation? A. Hybrid sterility B. Temporal isolation C. Habitat isolation D. Mechanical isolation

A

Which statement about inbreeding is correct? A. Inbreeding increases the rate of purifying selection. B. Inbreeding changes allele frequencies in a population. C. Offspring produced by inbreeding have high fitness. D. Inbreeding increases random mating.

A

Why does natural selection not produce populations that are perfectly adapted to their environment? A. Changing environments may change the nature of adaptive traits in a population. B. Genetic drift, gene flow, and mutation are evolutionary processes that do not lead to adaptation. C. Because mutations are rare, most populations have little heritable variation. D. There has not been enough time available for natural selection to produce populations that are perfectly adapted to their environment.

A

How did Dr. Allison test his hypothesis that sickle cell disease was connected to malaria? Select all that apply. A. He evaluated blood samples for malaria parasites and the presence of sickle cells. B. He looked for the underlying genetic mechanism causing sickle cell disease. C. He expanded his study area beyond Kenya to the rest of East Africa to see if malaria and sickle disease were connected. D. He studied the way that the malaria parasite interacts with sickle cells.

A and C

The enzyme lactase breaks the sugar lactose into which compound(s)? Select all that apply. A. galactose B. sucrose C. glucose D. fructose

A and C

In which country would you most likely find a higher incidence of lactase persistence? A. in a country in southern Africa where people historically have not consumed many dairy products B. in a Scandinavian country where people historically raised dairy cattle and made cheese C. in an Asian country where people historically did not raise cattle D. all of the above areas should have an equal incidence of lactase persistence

B

How could milk-drinking have provided strong favorable selection for lactase persistence? Select all that apply. A. Milk is protein and fat-rich and therefore could have been an important, high-quality food source. B. Milk was safer to drink than water and reduced exposure to pathogens. C. Milk may have been a critical food source during times of famine.

All

How does the term "lactase persistent" relate to the term "lactose tolerant"? A. A lactase-persistent person is lactose intolerant. B. A lactase-persistent person is lactose tolerant. C. Lactose tolerance has nothing to do with lactase-persistence.

B

Humans are diploid and have 46 chromosomes. How many chromosomes are found in each human gamete? A. 12 B. 23 C. 36 D. 45 E. 92

B

In the Hershey-Chase experiment, the material that entered cells upon infection by T2 virus was labeled with which radioactive isotope? A. 3H B. 32P C. 35S D. Both 32P and 35S

B

How did the 1977 drought on Daphne Major cause evolutionary change in the medium ground finch population? A. The drought was a particularly severe environmental perturbation. B. There was not enough food to support the medium ground finch population. C. Medium ground finches with large and deep beaks had higher survival rates during the drought. D. Medium ground finches learned to eat a different kind of seed.

C

How did the sunflower species Helianthus anomalus originate? A. Allopolyploidy B. Disruptive selection C. Hybridization D. Autopolyploidy

C

How do lactase supplements help people who are lactose intolerant? A. The supplements help replace the missing calcium and vitamins that people lack when they don't consume dairy products. B. The supplements bring about genetic changes that allow lactose intolerant people to produce lactase. C. The supplements provide the enzyme that breaks down the lactose in dairy products. D. The supplements create a nauseating feeling so that people are less likely to consume dairy products.

C

Lactose intolerance in infants is more common in the population today than it was a hundred years ago. Why? A. Today there is a much higher percentage of adults who are lactose intolerant but still choose to have children. B. Children today are not as healthy as children were a few hundred years ago. C. Today there are alternatives to breast milk, such as lactose-free formula and soy milk, so lactose intolerant infants can survive. D. The large number of pollutants and toxins in the environment has led to more infants becoming lactose intolerant.

C

Most people are lactose intolerant as adults, but nearly everyone produces sufficient lactase as an infant. However, in some cases, genetic mutations can occur that make an infant lactose intolerant. From an evolutionary perspective -- over thousands of years -- why would lactose intolerance in infants be very rare in the population? A. Infants who were lactose intolerant were intolerant of all other foods as well. B. Lactose intolerant adults were not healthy enough to have children. C. Lactose intolerant infants could not digest breast milk and therefore usually died, never having the chance to pass the mutation on to their children. D. Lactose intolerance was such an embarrassing problem that many lactose intolerant parents chose not to have children, since the children might be lactose intolerant as well.

C

Select the correct statement about gene flow. A. Gene flow increases genetic diversity within a population. B. Gene flow decreases genetic diversity within a population. C. Gene flow makes allele frequencies more similar between populations. D. Gene flow leads to random changes in allele frequencies in a population.

C

Suppose that Gene BB occurs in a sea turtle gene pool where the frequency of the B1B1 allele is 0.5 and the frequency of the B2B2 allele is 0.4.What is the frequency of the B3B3 allele, assuming that there are only three alleles in the population? A. The frequency of B3=(0.4)2=0.16B3=(0.4)2=0.16. B. The frequency of B3=0.9B3=0.9 because 0.5+0.4=0.90.5+0.4=0.9. C. The frequency of B3=0.1B3=0.1 because 0.5+0.4+?=10.5+0.4+?=1. D. There is not enough information to determine the frequency of the B3B3allele.

C

Why is the enzyme lactase necessary to digest dairy products? A. Lactase converts the lipids in dairy products into carbohydrates, so that they can be used for energy and raw materials. B. Lactase converts monosaccharides like lactose into disaccharides like glucose. C. Lactase breaks down lactose into smaller molecules that can be absorbed by the cells that line the small intestine. D. Lactase converts monosaccharides like glucose into disaccharides like lactose.

C

Why should we not view lactose intolerance as a disease in adult humans? A. Humans do not normally produce the lactase enzyme at any time during their lives. B. The dietary supplement available for lactose intolerant adults causes more harm than good. C. Adult humans did not consume dairy products until fairly recently in our evolutionary history. D. The ability to produce the lactase enzyme is common in adult humans, but rare in infants.

C

How does Dr. Allison's work provide an example of natural selection in humans? Select all that apply. A. Natural selection caused the sickle cell allele to appear in east African populations. B. In areas with malaria, natural selection causes individuals to acquire the sickle cell allele as protection against malaria. C. In areas with malaria, individuals with one sickle cell allele reproduced at higher rates than those with no sickle cell alleles. D. In areas without malaria, individuals with two sickle cell alleles reproduced at lower rates than those without sickle cell disease.

C and D

Predict how prickles ("thorns") originated in roses. A. With increasing numbers of herbivores, roses needed defenses to discourage them. Prickles developed on stems to keep them away. Individuals with these prickles survived herbivore attacks and produced more offspring than other roses, increasing the frequency of the prickled roses in the population over time. B. Chemicals in the saliva of herbivores triggered hormones in the roses that stimulated cell division in the stems, leading to prickles on their surface. Individuals with these prickles survived herbivore attacks and produced more offspring than other roses, increasing the frequency of the prickled roses in the population over time. C. Some roses hybridized with a close relative that had prickles. Individuals with these prickles survived herbivore attacks and produced more offspring than other roses, increasing the frequency of the prickled roses in the population over time. D. By chance, a mutation occurred in some roses that resulted in sharp bumps on the stems. Individuals with these early prickles survived herbivore attacks and produced more offspring than roses without the mutation, increasing the frequency of the prickled roses in the population over time.

D

Which evolutionary mechanism increases genetic variation in a population? A. Founder effect B. Genetic drift C. Genetic bottleneck D. Mutation

D

Which of the situations below describes vicariance? A. American bullfrogs expand their range into British Columbia. B. Four moose are transported from New Brunswick to Newfoundland, where they establish a large population. C. A small group of finches is blown from the mainland to a recently formed volcanic island. D. The Grand Canyon forms, separating two populations of squirrels on the North Rim and the South Rim.

D

Which of these terms applies to an organism with extra sets of chromosomes? A. monosomy B. haploid C. trisomy D. polyploid E. diploid

D

Which statement shows population thinking? A. Species do not change over time. B. All species can be organized into a sequence of increasing complexity. C. A single perfect specimen can represent a species. D. Variation among individuals in a species is real and important.

D

Why do related species share homologous traits? A. Related species have independently evolved homologous traits. B. Related species are adapted to similar environments. C. Related species share homologous traits because they are found in the same geographical area. D. Related species inherited homologous traits from a common ancestor.

D

_____ is the process by which haploid gametes form a diploid zygote. A. Embryogenesis B. Meiosis C. Gastrulation D. Fertilization E. Mitosis

D

Most polyploid plants arise as a result of _____. A. self-fertilization B. a mutation of gamete formation C. meiosis D. mitosis E. hybridization

E