BIO Unit 3

Chapter23,24,27,28,29

Alternative forms of a gene that influence the same trait and are found at the same location in homologous chromosomes are called



A. alleles.



B. phenotypes.



C. genotypes.



D. incomplete dominance.

alleles

Which of the following represents the physical characteristics of the individual?

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A. phenotype



B. genotype



C. alleles



D. dominance

phenotype

What are alleles?



A. genes for different traits, such as hair color and eye color



B. alternative forms of a gene for a single trait, such as blue eyes or brown eyes



C. the locations of genes on a chromosome



D. recessive forms of a kind of characteristic carried by genes

alternative forms of a gene for a single trait, such as blue eyes or brown eyes

The _____ indicates the gene combination of an individual.

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A. phenotype



B. loci



C. genotype



D. homozygous

genotype

Which of the following is NOT correct concerning the law of independent assortment?

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A. It is based upon the process of meiosis

B. Each pair of factors separates independently.

C. All possible combinations of factors can occur in the gametes.

D. It follows the observation that all maternal chromosomes end up in the egg.

It follows the observation that all maternal chromosomes end up in the egg.

Which is NOT true according to Mendel's law of segregation?



A. Each individual contains two alleles for each trait

B. An individual can have either both dominant alleles, both recessive alleles, or a dominant and recessive allele.

C. Alleles separate from each other during gamete formation.

D. Each gamete contains one copy of each allele.

E. Fertilization restores the presence of two alleles.

An individual can have either both dominant alleles, both recessive alleles, or a dominant and recessive allele.

Mendel's law of segregation implies that the two members of an allele pair

A. are distributed to separate gametes.

B. are distributed to the same gamete.

C. are assorted dependently.

D. are segregated pairwise.

are distributed to separate gametes.

In a Mendelian monohybrid cross involving two homozygous genotypes, the ____ generation is always completely heterozygous.



A. F1

B. F2

C. P

D. P2

F1

What will the genotypic ratio be of a monohybrid cross of two individuals who are both heterozygous for a trait?



A. 100% homozygous dominant

B. 50% homozygous dominant, 50% homozygous recessive

C. 25% homozygous dominant, 50% heterozygous, 25% homozygous recessive

D. 50% homozygous dominant, 50% heterozygous

25% homozygous dominant, 50% heterozygous, 25% homozygous recessive

A pheasant breeder starts with two birds in the P generation, one of which is AA and the other is aa. If he takes two of the birds from the F1 generation and breeds them together, what can he expect in his F2 offspring?



A. AA and Aa.

B. Aa and aa.

C. AA, Aa, and aa.

D. Aa only.

AA, Aa, and aa.

A woman who can roll her tongue (presumably dominant) is married to a man who cannot. Two of their four children can roll their tongues and two cannot. If A = roll tongue and a = cannot roll tongue, then what is the genotype of the parents?



A. woman Aa; man Aa

B. woman AA; man aa

C. woman Aa; man AA

D. woman Aa; man aa

woman Aa; man aa

Some plants fail to produce chlorophyll, due to a recessive trait. If we locate a pea plant that is heterozygous for this trait, self-pollinate it, and harvest the seeds, what are the likely phenotypes of the resulting offspring?



A. All will be green with chlorophyll since that is the dominant trait.

B. About one-half will be green and one-half white since that is the distribution of the genes in the parents.

C. About one-fourth will be white and three-fourths green since it is similar to a monohybrid cross.

D. About one-fourth will be green and three-fourths white since it is similar to a monohybrid cross.

About one-fourth will be white and three-fourths green since it is similar to a monohybrid cross.

A cross is made between two parents with genotypes AaBB and aabb. If there are 32 offspring, how many of them would be expected to exhibit both dominant characteristics?



A. 32

B. 24

C. 16

D. 8

E. 0

16

In guinea pigs, B = black, b = brown, S = short hair, s = long hair. A heterozygous black, short-haired animal reproduces with a brown, long-haired animal. What is the expected phenotypic ratio of the offspring?



A. 1 black short hair, 1 black long hair, 1 brown short hair, 1 brown long hair

B. 9 black short hair, 3 black long hair, 3 brown long hair, 1 brown short hair

C. 9 black short hair, 3 black long hair, 3 brown short hair, 1 brown long hair

D. 9 black short hair, 6 black long hair, 3 brown long hair, 1 brown short hair

1 black short hair, 1 black long hair, 1 brown short hair, 1 brown long hair

In humans, aniridia, a type of blindness, is due to a dominant allele A. Migraine headaches are due to another dominant allele M. If a man who suffers from both conditions (AaMm) marries a woman who suffers from both (AaMm), what are the chances of an offspring expressing both traits.



A. 9/16

B. 3/16

C. 1/2

D. 1/16

9/16

In which kind of cross could you expect to find ratios of 1:1:1:1 among the offspring?

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A. monohybrid cross

B. dihybrid cross

C. one-trait test cross

D. two-trait test cross

two-trait test cross

In guinea pigs, B = black, b = brown, S = short hair, s = long hair. Two heterozygous individuals reproduce. The expected results are



A. 9 black long hair, 3 black short hair, 3 brown long hair, 1 brown short hair.

B. 9 black short hair, 6 black long hair, 3 brown long hair, 1 black short hair.

C. 9 black short hair, 3 black long hair, 3 brown short hair, 1 brown long hair.

D. 9 brown short hair, 3 black long hair, 3 brown long hair, 1 black short hair.

9 black short hair, 3 black long hair, 3 brown short hair, 1 brown long hair.

What genetic disorder is associated with the lack of an enzyme necessary for the normal metabolism of the amino acid phenylalanine?

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A. phenylketonuria (PKU)

B. Huntington disease

C. sickle cell disease

D. cystic fibrosis (CF)

phenylketonuria (PKU)

Which genetic disorder is associated with an irregular shape of the red blood cells?

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A. sickle cell disease

B. Marfan syndrome

C. Huntington disease

D. cystic fibrosis (CF)

sickle cell disease

What are the chances that two individuals with wavy hair (an incomplete trait) will have a curly-haired child? Curly hair and straight hair exhibit incomplete dominance.



A. none

B. 25%

C. 50%

D. 75%

25%

The four o'clock flower is an example of incomplete dominance: R = red, r = white, and Rr = pink. If two hybrids are crossed, what are the chances that an offspring will have pink flowers?



A. 0%

B. 25%

C. 50%

D. 75%

E. 100%

50%

Traits that are controlled by several sets or pairs of alleles, such as skin color and height in humans, are the result of what form of inheritance?



A. polygenic

B. incomplete dominance

C. simple Mendelian inheritance

D. codominance

polygenic

Which of the following is an example of the blending of phenotypes?



A. codominance

B. polygenic inheritance

C. simple Mendelian inheritance

D. incomplete dominance

incomplete dominance

You have two true-breeding rose bushes, one with red flowers and one with white flowers. A cross between these two roses yields a bush with pink flowers. What condition does this demonstrate?



A. codominance

B. incomplete dominance

C. environmental effects

D. polygenetic inheritance

incomplete dominance

When two or more genes with multiple alleles affect the same trait in an additive fashion, it is termed



A. a double-trait cross.

B. codominant.

C. incomplete dominance.

D. polygenic inheritance.

polygenic inheritance

You have two true-breeding rose bushes, one with red flowers and one with white flowers. A cross between these two roses yields a bush with white flowers that have red splotches. What condition does this demonstrate?



A. codominance

B. incomplete dominance

C. environmental effects

D. polygenetic inheritance

E. monohybrid inheritance

codominance

Cold weather can change the ______ of a Himalayan rabbit.



A. genotype

B. phenotype

C. alleles

D. sex

phenotype

Hydrangeas are a flowering plant with large showy blooms. When a plant is grown in aluminum-rich soil it has blue flowers. If the same plant is transplanted into soil that is lacking aluminum, the flowers produced will be pink. This is an example of



A. codominance.

B. incomplete dominance.

C. environmental effects.

D. polygenetic inheritance.

environmental effects.

In peas, yellow is dominant over green in seeds. With which of these is it best to cross a yellow-seeded pea plant to determine whether it is homozygous or heterozygous?



A. a green-seeded plant

B. a heterozygous yellow-seeded plant

C. a pure yellow-seeded plant

D. a heterozygous yellow-seeded plant or a pure yellow-seeded plant

a green-seeded plant

In a testcross, an organism with a dominant phenotype, but unknown genotype is crossed with which of the following to establish its genotype?

 

A. homozygous dominant

B. heterozygous

C. homozygous recessive

D. heterozygous dominant

homozygous recessive

This pedigree documents an autosomal recessive trait. Remember, affected individuals are represented by filled in shapes. What is the genotype of individual 6 at generation II?



A. Homozygous Dominant

B. Homozygous Recessive

C. Heterozygous

D. There is not enough information given to tell.

Heterozygous

A man with AB blood type can have a child with type O.



A. True

B. False

False

What type of inheritance is represented by the above pedigree? Remember, affected individuals are represented by filled in shapes.



A. Autosomal Dominant



B. Autosomal Recessive

Autosomal Dominant

The location of a gene on a chromosome is called



A. a locus.

B. a linkage map.

C. a linkage group.

D. an allele.

a locus.

Considering that males can have Klinefelter (XXY) syndrome, XYY, and normal XY chromosomal combinations, and females can have Turner (XO) syndrome, poly-X (XXX, XXXX), and normal XX combinations, it is obvious that



A. maleness results from the presence of only one X chromosome.

B. maleness results from the absence of two or more X chromosomes.

C. maleness results from the minimal presence of one Y chromosome.

D. femaleness results from the presence of two or more X chromosomes.

maleness results from the minimal presence of one Y chromosome.

Genes on the ___ chromosome determine if the sex of a child will be male or female.



A. X

B. Y

C. 21st

D. 5th

Y

A normal male marries a color-blind woman. What percent of their female children will be color-blind?



A. 0%

B. 25%

C. 50%

D. 75%

E. 100%

0%

Color-blindness is inherited as an X-linked recessive trait. A male who is color-blind marries a heterozygous woman. What percent of their total children will be color-blind?



A. 0%

B. 25%

C. 50%

D. 75%

E. 100%

50%

A color-blind (recessive trait) woman will pass the allele to 



A. her sons only.

B. all her children.

C. her daughters only.

D. none of her children.

E. her husband.

all her children.

If a woman is a carrier for the color-blind recessive allele and her husband has normal vision, what are their chances that a son will be color-blind?



A. None, because the father is normal.

B. 50%, since the mother is only a carrier.

C. 100% because the mother has the gene.

D. 25% because the mother is a hybrid.

E. None since the son will also be just a carrier.

50%, since the mother is only a carrier.

. Which of the following sex-linked diseases is characterized by the absence of a clotting factor?



A. hemophilia

B. color-blindness

C. Duchenne muscular dystrophy

D. None of the answer choices is true.

hemophilia

Which refers to the loss of a complete chromosome?



A. inversion

B. translocation

C. deletion

D. monosomy

monosomy

Generally, it is not possible to determine whether nondisjunction failed to occur in oogenesis or spermatogenesis. However, it is possible to assert that _____ resulted in nondisjunction in ____.



A. XXY; oogenesis

B. XYY; spermatogenesis

C. XXX; oogenesis

D. XXY; spermatogenesis

XYY; spermatogenesis

When homologous chromosomes fail to separate during meiosis, this is termed



A. linked genes.

B. nondisjunction.

C. crossover.

D. monosomy.

nondisjunction.

An individual who has an XXY combination of sex chromosomes is said to have _____ syndrome.



 



A. Klinefelter

B. Turner

C. Down

D. cri du chat

Klinefelter

A person with an XO genotype is classified as having



A. Down syndrome.

B. Turner syndrome.

C. Klinefelter syndrome.

D. a poly-X state.

Turner syndrome.

Which refers to the loss of a portion of a chromosome?



A. inversion

B. translocation

C. deletion

D. duplication

deletion

Which refers to the movement of a piece of one chromosome to another nonhomologous chromosome?



A. inversion

B. translocation

C. deletion

D. duplication

translocation

If a chromosomal segment appears more than once in the same chromosome, it is termed a(n)



A. translocation.

B. duplication

C. deletion.

D. inversion.

duplication

Which refers to the addition of a repeat segment of a chromosome?



A. inversion

B. translocation

C. deletion

D. duplication

duplication

If a chromosomal segment is turned around 180°, the chromosomal mutation is termed a(n)

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A. translocation.

B. duplication.

C. deletion.

D. inversion.

inversion.

Fruit flies of the species *Drosophila melanogaster* are an important model organism for eukaryotic genetics. The genes for olive body color and purple eye color are on the same chromosome. Consider an organism with the chromosomes in the diagram above. What process is capable of producing a gamete with the alleles "pO"? 



A. Crossing Over

B. Mitosis

C. Independent Assortment

D. Nondisjunction

Crossing Over

Consider the above diagram. The eggs and the resulting gametes would be the result of nondisjunction in 



A. Meiosis I.

B. Meiosis II.

Meiosis I.

All cases of Down syndrome are caused by trisomy of chromosome 21.



A. True

B. False

False

The above pedigree pertains to colorblindess. What is the genotype of the individual indicated by the asterisk?



A. XB Xb

B. XB XB

C. Xb Xb

D. XB Y

XB Xb

According to Lamarck, which variable would have the greatest influence on the evolution of an organism?



A. the environment

B. the genetics of the individual

C. Both the environment and genetics are equally responsible for the evolution of an organism.

D. Neither the environment nor the genetics of an organism play a role in its evolution.

the environment

Lamarck's proposal of the inheritance of acquired characteristics included the idea that



A. the continual stretching of giraffe's necks to reach leaves led to longer necks in offspring.

B. local catastrophes cause mass extinctions of species.

C. species are fixed and unchanging over time.

D. organisms are acted on by the environment.

the continual stretching of giraffe's necks to reach leaves led to longer necks in offspring.

When he arrived at the Galápagos Islands, Darwin did not observe the amazing tool-using "woodpecker finch" that can modify twigs to pry out grubs. Because there are no true woodpeckers on the Galápagos Islands, this behavior allows this finch to exploit an untapped food source. However, not all members of this species exhibit this behavior, which is probably learned from watching other finches. Therefore, which of the following is NOT true?



A. Young isolated at hatching will not know how to do this.

B. It is probably not "hardwired" in the brain as a behavior passed on genetically.

C. There must be a great advantage to reaching this food source for this learned behavior to be repeated by most descendants each generation.

D. This "learned" behavior will not lead to evolutionary change in the woodpecker population.

This "learned" behavior will not lead to evolutionary change in the woodpecker population.

Which piece of evidence did Darwin observe during his 5-year journey aboard the HMS Beagle?



A. A South American species of finch is most likely the ancestor of the Galápagos Island finches.

B. Species do not change over time.

C. All species share the same basic genetic and molecular makeup.

D. The earth is approximately 4.6 billion years old.

A South American species of finch is most likely the ancestor of the Galápagos Island finches.

What evidence would NOT be studied by a biogeographer?



A. continental drift or the movement of tectonic plates over time

B. ocean currents and wind patterns

C. ranges of animals and ability to migrate

D. the genetic makeup of organisms that evolved in separate but similar conditions

the genetic makeup of organisms that evolved in separate but similar conditions

Which evidence for evolution uses impressions of plants and animals pressed into sedimentary rock?



A. fossil record



B. biogeography



C. comparative embryology



D. comparative biochemistry

fossil record

Anatomical features that are fully developed and functional in one group of organisms but reduced and functionless in a similar group are termed

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A. vestigial.

B. homologous.

C. analogous.

D. sympatric.

vestigial

Which of these conditions is NOT among the requirements of the Hardy-Weinberg equilibrium?



A. no net mutations

B. no net migration of alleles into or out of the population

C. small population with genetic drift

D. no selection of one genotype over another

small population with genetic drift

If the Hardy-Weinberg equilibrium is met, what is the net effect?

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A. evolution leading to a population better adapted to an unchanging environment

B. evolution leading to a population better adapted to a changing environment

C. very slow and continuous evolution with no increased adaptation

D. no evolution because the alleles in the population remain the same

no evolution because the alleles in the population remain the same

Which statement is NOT true about the founder effect?



A. It is a form of genetic drift.

B. It produces a high frequency of some rare alleles in a small isolated population.

C. Founding members contain a tiny fraction of the alleles found in the original population.

D. The founder effect occurs when a population is subjected to near extinction and then recovers, so that only a few alleles are left in survivors.

The founder effect occurs when a population is subjected to near extinction and then recovers, so that only a few alleles are left in survivors.

When only a few individuals survive unfavorable times, thereby losing the majority of genotypes in the next generation, it is called



A. natural selection.

B. a bottleneck effect.

C. a founder effect.

D. industrial mechanism.

a bottleneck effect

Which of the following is true about genetic drift?



A. It may lead to an allele becoming fixed in a population when its alternative allele is lost from the population.

B. It increases the number of heterozygotes in a population.

C. It increases the level of rare alleles in a population.

D. It reduces the chances of mutation in a population.

It may lead to an allele becoming fixed in a population when its alternative allele is lost from the population

A random alteration in the sequence of DNA nucleotides that provides a new variant of the gene is



A. gene mutation.

B. gene frequency.

C. disruption.

D. allele frequency.

gene mutation

Movement of alleles between populations such as by the migration of breeding individuals is called



A. genetic drift.

B. gene flow.

C. nonrandom mating.

D. natural selection.

gene flow

Which of the following conditions does NOT contribute to evolution?



A. mutations

B. gene flow

C. genetic drift

D. unchanging environmental conditions

unchanging environmental conditions

Inbreeding within a population is an example of



A. genetic drift.

B. gene flow.

C. nonrandom mating.

D. natural selection.

nonrandom mating.

Disruptive selection is described in the text with the case of British land snails. In the grassy fields, the light-banded snails escape bird predators. In the darker forest, the dark snails survive and the light-banded snails are eaten. As long as the snails continue to cruise across the British landscape mating at the same season and having access to each other, why doesn't this "disruptive selection" eventually lead to two separate species?



A. There is no reproductive isolation to prevent gene flow.

B. They are already two separate species and the intermediate forms are hybrids.

C. The color forms are probably not genetically determined.

D. There must be some unknown factor producing an equal stabilizing selection "to hold the species together."

E. This will result in the formation of two species if given long enough time.

There is no reproductive isolation to prevent gene flow.

Which type of natural selection occurs when an intermediate phenotype is favored?



A. disruptive selection

B. directional selection

C. stabilizing selection

D. genetic drift selection

E. adaptive radiation

stabilizing selection

Which type of natural selection increases the frequency of one extreme phenotype?



A. directional

B. stabilizing

C. disruptive

D. nonrandom

directional

The model of speciation that requires some time with geographic barriers between two populations, allowing evolution of reproductive isolation, is



A. allopatric speciation.

B. phyletic gradualism.

C. sympatric speciation.

D. punctuated equilibrium.

E. prezygotic isolation.

allopatric speciation.

During sympatric speciation



A. evolution ceases for a time.

B. wide phenotype differences disappear between subpopulations.

C. reproductive isolation between certain subpopulations occurs.

D. a geographic separation occurs between certain subpopulations.

E. mutations begin to appear, making the subpopulations distinctly different

reproductive isolation between certain subpopulations occurs.

During allopatric speciation

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A. gene flow continues between subpopulations.

B. reproduction between all subpopulations is impossible.

C. a geographic separation occurs between subpopulations.

D. wide phenotype differences appear between subpopulations.

E. subpopulations are still able to interbreed.

a geographic separation occurs between subpopulations.

Which of the following species are most closely related?



A. human and green monkey

B. gibbon and capuchin

C. green monkey and capuchin

D. galago and green monkey

human and green monkey

Which of the following species are most closely related?



A. chimpanzee and rhesus monkey

B. gibbon and capuchin

C. rhesus monkey and capuchin

D. galago and green monkey

chimpanzee and rhesus monkey

Which of the following species are most closely related?



A. gibbon and green monkey

B. gibbon and capuchin

C. green monkey and capuchin

D. galago and capuchin

gibbon and green monkey

The fin of a tuna and the flipper of a dolphin are



A. analogous structures.

B. homologous structures.

C. homogeneous structures.

D. reciprocal structures.

analogous structures.

Lizards on a small island are more likely to have to mate with close relatives. The form of microevolution is



A. the founder effect.

B. mutation.

C. gene flow.

D. natural selection.

the founder effect.

Cheetahs are very genetically similar, meaning there is not a lot of genetic diversity in their gene pool. It appears that at least 2 times in the last 10,000 years cheetah populations crashed to very low numbers. The present day low genetic diversity is due to _____________.



A. the bottleneck effect.

B. the founder effect.

C. natural selection.

D. non-disjunction.

the bottleneck effect.

A population of mice live in a grassy area near a stream. Some individuals have alleles that give them white fir while others have alleles for brown fur. A family of hawks move in and nest nearby. The hawks catch the white mice at a higher rate because those mice do not blend in to the surroundings so well. This changes the genetic makeup of the population and a higher percentage of the next generation of mice have brown fur. This is an example of _______.



A. Natural Selection

B. Genetic Drift

C. Mutation

D. Gene Flow

Natural selection

A population of mice live in a grassy area near a stream. Some individuals have alleles that give them white fir while other have alleles for brown fur. One day the stream floods killing a higher percentage of mice with the brown alleles basically at random. This changes the genetic makeup of the population and a higher percentage of the next generation of mice have white fur. This is an example of



A. Natural Selection

B. Genetic Drift

C. Mutation

D. Gene Flow

Genetic Drift

A population of mice live in a grassy area near a stream. Some individuals have alleles that give them white fir while others have alleles for brown fur. One day a mouse is born in which an allele for brown fur has change and causes the mouse to be tan. This is an example of

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A. Natural Selection

B. Genetic Drift

C. Mutation

D. Gene Flow

Mutation

. In Arkansas, the gray tree frog breeds in March, while the closely related species Harpers frog breeds at the end of May. This is an example of a ___________________ isolating mechanism.

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A. habitat

B. temporal

C. behavioral

D. mechanical

E. post zygotic

temporal

Two species of peas are visited by the same species of bee. Each species of pea has its stamens positioned to place pollen on different parts of the bee's body. Upon visiting other flowers, the pollen from the bee can only get on the female parts of the same species. This is an example of a ___________________ isolating mechanism.



A. habitat

B. temporal

C. behavioral

D. mechanical

E. post zygotic

mechanical

. In peacock spiders, a male displays before a female. If the male is of the wrong species then the female will reject him because he does not do the correct courtship display or have the correct color patterns. This is an example of a ___________________ isolating mechanism.



A. habitat

B. temporal

C. behavioral

D. mechanical

E. post zygotic

behavioral

Red-legged frogs and Bullfrogs can interbreed in the lab. However, Red-legged frogs only breed in fast-moving streams and Bullfrogs only breed in ponds. This is an example of a _______________ isolating mechanism.



A. habitat

B. temporal

C. behavioral

D. mechanical

E. post zygotic

habitat

Microbiology is the study of microbes. These include all but which of the following?



A. Archaea

B. Bacteria

C. viruses

D. plants

plants

What general feature is necessary to consider an organism a microbe?



A. small enough that a microscope is required to see them

B. heterotrophic

C. sexual reproduction

D. use aerobic respiration for metabolism

small enough that a microscope is required to see them

Miller's laboratory experiments showed that



A. it is possible to form protocells.

B. the primitive gases can react together to produce small organic molecules.

C. atmospheric pressure is required for life to begin.

D. the earth is approximately 4.5 billion years old.

the primitive gases can react together to produce small organic molecules.

Which of the following kinds of molecules is thought to have been absent from the primitive reducing atmosphere?



A. water vapor (H2O)

B. methane (CH4)

C. hydrogen (H2)

D. oxygen (O2)

oxygen (O2)

Considering the various theories, the energy used in forming organic molecules in the primitive atmosphere could have come from all EXCEPT

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A. lightning.

B. ultraviolet radiation.

C. heat from volcanoes.

D. sound.

sound.

What is the evolutionary relationship among archaea, bacteria, and eukarya?



A. Since archaea are the most primitive, archaean ancestors gave rise to bacteria that in turn gave rise to eukaryotes.

B. All three domains are equally distant from the most primitive common ancestor, a protocell.

C. Archaea and eukarya share nucleic acid similarities, so eukarya split off from archaea.

D. Bacterial ancestors gave rise to both archaea and to eukaryotes as two separate side branches.

Archaea and eukarya share nucleic acid similarities, so eukarya split off from archaea.

A new classification by domains separates prokaryotes into



A. Bacteria and Cyanobacteria.

B. photosynthetic bacteria and chemosynthetic bacteria.

C. Archaea and Bacteria.

D. autotrophs and heterotrophs.

Archaea and Bacteria.

One bacterial cell passes DNA to a second cell through a sex pilus in the process of



A. transformation.

B. transduction.

C. conjugation.

D. replication.

conjugation.

Bacterial cells pick up free pieces of DNA from the medium pieces that were released from dead bacteria in a process called



A. transformation.

B. transduction.

C. conjugation.

D. replication.

transformation.

Which of these is a correct description of a form of horizontal gene transfer in bacteria?



A. Crossing-over occurs between paired chromosomes in meiosis.

B. Conjugation occurs when a cell passes DNA to another cell by means of a sex pilus.

C. Transformation occurs when a bacteriophage carries a bit of DNA from a previous host cell to a new host cell.

D. Transduction occurs when a live bacterium picks up DNA from dead bacteria that have shed it into the environment of the living cell.

Conjugation occurs when a cell passes DNA to another cell by means of a sex pilus.