BIO 110 Exam 4

In unicorns, three alleles at a gene determine the condition of the horn. The allele for a twisted horn, HT, and the allele for a long horn, HL, are codominant; both are completely dominant to the hornless allele, h. The frequency of hornless individuals in the population is 16%, and the frequency of the allele for twisted horns is 0.1. What is the frequency of the long horn allele?

.50 (50%)

What is the frequency of the A1A2 genotype in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?

0.4

Human blood types are, in part, determined by the ABO system. The allele frequency for blood type IA is 0.3, and IB is 0.1. What is the frequency of the allele that codes for no carbohydrate (type O) and is designated i?

0.6

In a population of heffalumps, there is a single gene that controls the presence of hair. The H allele, which is a complete dominant, makes a heffalump hairy, whereas the h allele codes for the absence of hair. If 36% of the heffalump population is hairless, what is the frequency of the h allele?

0.60

In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population?

0.80

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with AA genotype?

0.81

Here are four individual strands of DNA: 1- 5'AATTCCGGCCTAACTT3' 2- 5'AAGTTAGGCCGGAATT3' 3- 5'TTAAGGCCGGATTGAA3' 4- 5'TTCAATCCGGCCTTAA3' Which strands would pair with one another?

1 and 2, 3 and 4

Below are four DNA sequences. Which pair(s) encodes alleles of the same gene? 1-attcgctaacgca 2-accggcaacattc 3-attccctaactca 4-acccgcatcattc

1 and 3, 2 and 4

In unicorns, three alleles at a gene determine the condition of the horn. The allele for a twisted horn, HT, and the allele for a long horn, HL, are codominant; both are completely dominant to the hornless allele, h. The frequency of hornless individuals in the population is 16%, and the frequency of the allele for twisted horns is 0.1. What frequency of individuals in the population have horns that are long and twisted?

10%

An example of a prezygotic reproductive barrier between species is __________________________.

gametic incompatibility

The ease with which humans travel across the globe is likely to increase _____.

gene flow

All the genes in a population are that population's _____.

gene pool

A bottleneck event can lead to ________.

genetic drift

Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans.

genetic drift

The difference in allele frequencies of retinitis pigmentosa between the two populations was likely due to __________________.

genetic drift brought on by a founder event

You are working at a fossil dig and find skeletons of two marine reptiles that you hypothesize were the same species. In arriving at this conclusion, you used which of the following concepts to define a species?

morphological species concept

Which of the following evolutionary forces could create new genetic information in a population?

mutation

Natural selection ultimately depends on favorable what?

mutations

A new disease wiped out the majority of a population. The only individuals that survived were homozygous for a recessive allele that encodes for a form of an enzyme that is unaffected by the disease toxin. (The converse is true for the dominant allele that encodes for a form of the enzyme that is affected by the toxin.) This is an example of ___________________.

natural selection

Which of the following conditions would favor a stable allele frequency for a particular gene in a population?

random mating

According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.

sexual reproduction

What mode of natural selection acts to cull out (remove) individuals that deviate in both directions from the mean in a normal population?

stabilizing selection

In Puerto Rico, Eleutherodacytlus locustus and Eleutherodactylus eneidae live in the same geographic area, El Yunque, and have somewhat similar mating calls. However, males of E. locustus call early in the evening, while males of E. eneidae don't begin to call until after midnight, peaking at about 3 a.m. This might be an example of what type of reproductive isolation?

temporal

Two species of orchids flower at different times of the year but live in the same location. As a consequence, they rarely produce hybrid offspring. This is an example of ____________ reproductive isolation.

temporal

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus

the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change.

An example of directional selection would be ___________________.

the disappearance of seals with thick fur and the increase in seals with thin fur as ocean waters warm

Genetic drift is a process based on _____.

the role of chance

DNA strands are called antiparallel because of _______________.

the two strands having opposite polarities

A mutation occurs when _____.

there is a change in the DNA sequence of a gene

The process of DNA replication is semiconservative. This means that a replicated chromosome is composed of:

two DNA molecules (sister chromatids), each with one newly synthesized strand of DNA and one parental (templatE. strand of DNA.

In eukaryotes, transcription takes place in the ______________________________.

Nucleus

Transfer RNA (tRNA) functions in ___________________.

Polypeptide elongation

There are numerous instances where environmental conditions profoundly affect phenotypes. Which of the following is probably NOT an example of the environment causing differences on the same genotype?

Populations of the milk snake (Lampropeltis triangulum) in the southeastern United States have a banded pattern consisting of alternating red, black, and yellow bands, which mimics a poisonous snake (the eastern coral snake. in the same geographical area. Populations of the milk snake in the northeastern United States (including Centre County) have a blotched pattern, which blends in easily with dead leaves.

Which of the following evolutionary forces consistently results in adaptive changes in allele frequencies?

Selection

Which of the following must exist in a population before natural selection can act upon that population?

Sexual reproduction and genetic variation among individuals

Natural selection is often described as the "survival of the fittest." Why is this description misleading?

This description implies that the individuals who live the longest will be the most fit.

True or false? The Hardy-Weinberg model makes the following assumptions: no selection at the gene in question; no genetic drift; no gene flow; no mutation; random mating.

True

Examples of stabilizing selection are most likely seen in which environment?

a deep ocean floor with constant conditions

An example of diversifying selection is ________________.

a population of plants that have both short and tall individuals, with few intermediate height plants, over many generations

An example of stabilizing selection is ________________.

a population of worms in which most individuals are intermediate in length over many generations.

Which of the following is an example of assortative mating?

a tell female chooses a tall male as a mate

An adaptation is _____.

a trait that gives an organism a reproductive advantage in the current environment

An example of sexual selection is ___________________________.

aggressive behavior seen only in males

The genotype is to an individual as the _____________ is/are to the population.

allele frequency

A group of lizards inhabit a prairie in North Dakota. A highway was constructed through the prairie forty years ago, creating northern and southern populations of the lizards. A group of students from North Dakota State University has created tunnels under the highway to connect the two populations; however, it does not appear that individuals from the two populations are successfully interbreeding. This is an example of __________________________.

allopatric speciation

You are studying a population of 20 panda bears. This population would _____________________.

be subject to genetic drift and evolutionary change

A male killdeer (a bird that lives in meadows and fields in Pennsylvania. emits a loud screech to attract the attention of a female killdeer, which will then choose whether or not to mate with the male. This behavior does not appeal to burrowing owl females, who have no interest in the male killdeer. This screeching behavior is an example of ____________________.

behavioral isolation

Wolves and coyotes have been known to produce fertile hybrid offspring in the wild. This makes them the same species according to the _____________________________.

biological species concept

According to the morphological species concept, two organisms are different species if they __________________________________.

display measurable anatomical differences

Which of the following is an example of the founder effect?

A group of 15 male and female birds from one species are stranded on an island.

What is not a part of the Hardy-Weinberg principle?

The genotype frequencies in the offspring generation must add up to two.

In the mid-1970's the population of Tristan du Cunha was about 250, and four individuals were affected with retinitis pigmentosa. This disease is inherited in an autosomal recessive manner. At that time, what was the approximate frequency of the allele in the population?

12%

Human blood types are, in part, determined by the ABO system. The allele frequency for blood type IA is 0.3, and IB is 0.1. What is the frequency of B-type individuals in a population?

13%

The incidence of retinitis pigmentosa in Britain is about 1:2500. What is the approximate allele frequency in Britain's population?

2%

In human gamete production there is an average of _____ crossover events per chromosome pair.

2-3

You are working for the Peace Corps in New Guinea and notice that about 4% of individuals have a debilitating disease. After doing a pedigree analysis, you determine it is an autosomal trait that shows a recessive expression pattern. What is the frequency of the deleterious (harmful) allele in the population?

20%

The following is a strand of mRNA: 5'AUUCGGCAUUCC 3' Which of the following DNA strands is its template? 1- 5'TAAGCCGTAAGG 3' 2- 5'GGAAUGCCGAAU 3' 3- 5'GGAATGCCGAAT 3' 4- 5'AUUCGGCAUUCC 3'

3

For the mRNA sequence 3' UAC 5', what is the appropriate tRNA anticodon?

3' GUA 5'

A DNA sequence reads 3' AGGCTTA 5'. Therefore, the complementary DNA strand must read _______________.'

3' TAAGCCT 5'

The following enzymes are involved in DNA replication on the lagging strand: 1-ligase 2-primase 3-helicase 4-polymerase In order for normal DNA replication to occur, these enzymes must work in the following order:

3,2,4,1

In the last question, you calculated the frequency of the deleterious allele in the population. How many individuals in the village would be carriers for this disease?

32%

The following is an mRNA sequence: 5'-AAUCCAUUU-3' Which of the following sets of anticodons would associate during translation? 1- 5'-TTAGGTAAA-3' 2- 5'-UUAGGUAAA-3' 3- 5'-AAATGGATT-3' 4- 5'-AAAUGGAUU-3'

4

You sample a population of butterflies and find that 56% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population?

Allele frequency cannot be determined from this information.

All of the following are directly required for protein synthesis EXCEPT __________________. DNA polymerase tRNA ribosomes RNA polymerase

DNA Polymerase

Which of the following mutations would likely be most dangerous to a cell? Deletion of three nucleotides Deletion of one nucleotide Substitution of one nucleotide for another

Deletion of one nucleotide

What are the basic components of the Hardy-Weinberg model?

Frequencies of two alleles in a gene pool before and after many random matings

Which of these statements about natural selection is false?

Natural selection, over time, can produce a perfect organism.

What genotype frequencies are expected under Hardy-Weinberg equilibrium for a population with allele frequencies of p = 0.8 and q = 0.2 for a particular gene?

The expected genotype frequencies are 0.64, 0.32, and 0.04 for A1A1, A1A2 , and A2A2 , respectively.

What is the frequency of the A1 allele in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?

The frequency of the A1 allele is 0.3.

Which of the following individuals would be most fit?

The individual who produces the most offspring

DNA is a self-replicating molecule. What accounts for this important property of DNA?

The nitrogenous bases of the double helix are paired in specific combinations: A with T and G with C.

A group of small fish live in a lake with a uniformly light-brown sandy bottom. Most of the fish are light brown, but about 10% are mottled. This fish species is often prey for large birds that live on the shore. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction of what will happen to this fish population?

The proportion of mottled fish will increase over time.

If an allele arises in a population of plants that results in taller plants, what effect might this have on plants that do not have this allele?

The shorter plants would receive less light, and therefore less energy.

The principles of heredity, first discovered by Mendel, are important to understanding Darwin's theory of the evolution of life by means of natural selection because they show that ________________.

genetic variation is preserved between generations

In eukaryotes, DNA replication takes place:

in the nucleus during interphase.

Sympatric speciation occurs when _______________________________________.

individuals live in the same area

A mutation in the DNA sequence of a gene that codes for a protein:

is only heritable if it occurs in a gamete producing cell

Lagging strand replication is made possible by the presence of ________________.

ligases

All of the following take place in the nucleus of a eukaryotic cell except ______________. -tRNA synthesis -linkage of an amino acid to its appropriate tRNA molecule -DNA replication -mRNA synthesis

linkage of an amino acid to its appropriate tRNA molecule

Homologous pairs of chromosomes are lined up independently of other such pairs during _____.

metaphase I

Which of the following is NOT a condition necessary to maintain Hardy-Weinberg equilibrium (genetic stability)?

no genetic variation among individuals

Crossing over, resulting in an increase in genetic variation, occurs between _____

nonsister chromatids of homologous chromosomes

The genetic code is said to be "redundant" because _____________________________________.

one amino acid can have more than one codon

Captive coyotes and domestic dogs are capable of mating and producing viable offspring. In their natural habitats, however, domestic dogs and coyotes have overlapping ranges but hybrids are rare; when seen, they often have health problems. The most likely reproductive barrier is _______________________________________.

postzygotic isolation

A gene pool consists of all of the alleles _____________________.

present in population at a given point in time