Biology Exam 2 - Practice Test

Front 1

1) The genetic makeup of an individual is the:
A) genotype.
B) sex cells.
C) gene pool.
D) phenotype.
E) mutation

Back 1

genotype.

Front 2

2) Modern geologists estimate that the age of Earth is about:
A) 4.5 trillion years.
B) 450,000 years.
C) 4.5 billion years.
D) 4.5 million years.
E) 4,500 years.

Back 2

4.5 billion years.

Front 3

3) Which of the following can evolve?
A) individuals
B) populations
C) communities
D) genes

Back 3

populations

Front 4

4) Inheritable mutations in the genes of an individual arise due to:
A) random chance.
B) vigorous exercise or effort.
C) environmental change.
D) artificial selection.
E) other species in the environment.

Back 4

random chance.

Front 5

5) Populations that were once considered separate species are sometimes reassigned to the same species because:
A) they have evolved to look the same.
B) they have evolved to look different from each other.
C) it was discovered that they can produce viable and fertile offspring.
D) they are no longer capable of interbreeding.
E) they have been found to be genetically identical.

Back 5

it was discovered that they can produce viable and fertile offspring.

Front 6

6) Which of the following is found in RNA but NOT in DNA?
A) thymine
B) phosphate groups
C) deoxyribose
D) uracil
E) adenine

Back 6

uracil

Front 7

7) All of the following may be found in a DNA nucleotide EXCEPT:
A) adenine.
B) phospholipid.
C) thymine.
D) deoxyribose.

Back 7

phospholipid.

Front 8

8) A population is defined as:
A) all individuals of the same species located throughout the world
B) all individuals of all species located in a given country.
C) all individuals of the same species located in a given geographic region.
D) those individuals of the same species that have an identical genetic makeup.
E) all individuals of all species located throughout the world.

Back 8

all individuals of the same species located in a given geographic region.

Front 9

9) The process by which allele frequencies are altered in a population due to chance is called:
A) assortative evolution.
B) random evolution.
C) genetic drift.
D) random mutation.
E) fitness.

Back 9

genetic drift.

Front 10

10) In DNA, phosphate binds to:
A) deoxyribose.
B) adenine.
C) ribose.
D) other phosphate molecules.

Back 10

deoxyribose.

Front 11

11) What type of allele produces its effects in only homozygous individuals?
A) diploid
B) dominant
C) recessive
D) haploid

Back 11

recessive

Front 12

12) Which of the following statements about mutations is TRUE?
A) Mutations are caused by natural selection.
B) Mutations are almost always better for the organism.
C) Mutations occur at random and are by chance.
D) Mutations have no effect on the survival and reproduction of an organism.
E) Mutations almost always leave the organism worse off than before.

Back 12

Mutations occur at random and are by chance.

Front 13

13) Semiconservative DNA replication means that:
A) only half of the DNA is replicated.
B) each new DNA molecule has half the DNA from the old one.
C) the old DNA is completely broken down.
D) A pairs with T and G pairs with C.
E) the old DNA remains completely intact.

Back 13

each new DNA molecule has half the DNA from the old one.

Front 14

14) One theory holds that the first self-replicating molecules were:
A) DNA.
B) amino acids.
C) lipids.
D) carbohydrates.
E) RNA.

Back 14

RNA.

Front 15

15) In DNA, phosphate groups bond to:
A) adenine.
B) other phosphate groups.
C) ribose.
D) pyrimidine bases.
E) deoxyribose.

Back 15

deoxyribose.

Front 16

16) What compounds were used in Miller and Urey's experiment to simulate the atmosphere of early Earth?
A) ammonia, hydrogen, and carbon dioxide
B) water, ammonia, hydrogen, and methane
C) water, oxygen, hydrogen, and methane
D) water, oxygen, ammonia, and methane
E) oxygen, ammonia, hydrogen, and methane

Back 16

water, ammonia, hydrogen, and methane

Front 17

17) Gregor Mendel concluded that each pea has two units for each trait, and each gamete contains one unit. Mendel's "units" are now called:
A) transcription factors.
B) alleles.
C) characters.
D) genes.

Back 17

genes.

Front 18

18) Mutations:
A) limit the potential for evolution.
B) arise due to environmental pressures.
C) are caused by natural selection.
D) can be helpful, neutral, or harmful to individuals.

Back 18

can be helpful, neutral, or harmful to individuals.

Front 19

19) The first multicellular eukaryotic fossils were:
A) cyanobacteria.
B) amphibians.
C) reptiles.
D) fungi.
E) algae.

Back 19

algae.

Front 20

20) If the quantities of the four bases in a DNA molecule are measured, we find that:
A) A = G and C = T.
B) A = C and G = T.
C) T = A and C = G.
D) no two bases are equal in amount.
E) all bases are equal in amount.

Back 20

T = A and C = G.

Front 21

21) All of the following are found in DNA EXCEPT:
A) thymine.
B) a phospholipid group.
C) a phosphate group.
D) deoxyribose.
E) guanine.

Back 21

a phospholipid group.

Front 22

22) Evolution can be defined as:
A) an individual changing into another species.
B) one species diverging into two species.
C) a change in the phenotype of an individual over his or her lifetime.
D) a change in the genetic makeup of an organism over time.
E) a change in the genetic makeup of a population over time.

Back 22

a change in the genetic makeup of a population over time.

Front 23

23) According to the law of segregation, in an organism with the genotype Aa:
A) all the gametes have gene a.
B) 1/4 of the gametes have A and 3/4 have a.
C) half the gametes have A and half have a.
D) all the gametes have gene A.
E) 3/4 of the gametes have A and 1/4 have a.

Back 23

half the gametes have A and half have a.

Front 24

24) One species of fish feeds in the muddy bottom of a lake. A second species eats insects that land on the water surface. This is an example of:
A) geographic isolation.
B) ecological isolation.
C) behavioral isolation.
D) mechanical incompatibility.
E) temporal isolation.

Back 24

ecological isolation.

Front 25

25) Who wrote On the Origin of Species by Means of Natural Selection?
A) Darwin
B) Mendel
C) Lamarck
D) Malthus
E) Smith

Back 25

Darwin

Front 26

26) Shrews have been documented to travel across frozen lakes and establish populations on previously uninhabited islands. This is an example of:
A) genetic drift.
B) the founder effect.
C) a population bottleneck.
D) assortative mating.
E) coevolution.

Back 26

the founder effect.

Front 27

27) In many species of fireflies, males flash light from their abdomens to attract females. Each species has a different flashing pattern. This is an example of:
A) temporal isolation.
B) ecological isolation.
C) geographic isolation.
D) behavioral isolation
E) mechanical incompatibility.

Back 27

behavioral isolation

Front 28

28) Multicellularity enables organisms to:
A) be photosynthetic.
B) reproduce more efficiently.
C) be big.
D) be fast.
E) undergo aerobic respiration.

Back 28

be big.

Front 29

29) The first terrestrial animals were probably:
A) amphibians.
B) dinosaurs.
C) reptiles.
D) arthropods.
E) mammals.

Back 29

arthropods.

Front 30

30) What is the total number of different possible combinations of bases in a codon?
A) 3
B) 4
C) 64
D) 20

Back 30

64

Front 31

31) The physical manifestation of an organism's genes is its:
A) phenotype.
B) environment.
C) genetic code.
D) number of chromosomes.
E) genotype.

Back 31

phenotype.

Front 32

32) Darwin realized that most species produce many more offspring than is necessary to maintain a constant population. The "excess" individuals in a population:
A) migrate to another location.
B) mutate and are able to adapt to new environments.
C) die before they can reproduce.
D) evolve to become new species.

Back 32

die before they can reproduce.

Front 33

33) Imagine that one of the original four mice that escape from a research lab is blind due to a genetic defect. If the mice breed and most of the mice born in subsequent generations are blind from birth, this is most likely a case of:
A) natural selection.
B) artificial selection.
C) the founder effect.
D) selective mutation.
E) an equilibrium population.

Back 33

the founder effect.

Front 34

34) Two populations of flowers look identical but are pollinated by different pollinators?one by a night-flying hummingbird moth, the other by honeybees. These two flowers represent:
A) identical gene pools.
B) the same species using different pollinators.
C) groups within the same species.
D) identical evolutionary paths.
E) different species.

Back 34

different species.

Front 35

35) If we cross two pea plants, each heterozygous for yellow seed color genes, the expected ratio of yellow:green among the offspring will be:
A) 100% green.
B) 25% yellow:75% green.
C) 75% yellow:25% green.
D) 100% yellow.
E) 50% yellow:50% green.

Back 35

75% yellow:25% green.

Front 36

36) Fossils include rocks and sediments that:
A) bear the impressions or shapes of preserved organisms.
B) have been shaped by people to resemble plants or animals.
C) have been shaped by wind and water to resemble lifelike forms.
D) all of the above.

Back 36

bear the impressions or shapes of preserved organisms.

Front 37

37) Habitat loss, natural catastrophes, and/or excessive harvesting of a species often result in:
A) increased gene flow.
B) increased mutation rates.
C) increased fitness of individuals.
D) artificial selection.
E) population bottlenecks.

Back 37

population bottlenecks.

Front 38

38) Which of the following is the correct sequence of stages in mitotic cell division?
A) anaphase-telophase-prophase-metaphase
B) telophase-anaphase-prophase-metaphase
C) prophase-metaphase-anaphase-telophase
D) metaphase-prophase-anaphase-telophase

Back 38

prophase-metaphase-anaphase-telophase

Front 39

39) The modern-day group of vertebrates that bridges the evolutionary gap between land-dwelling and water-dwelling organisms is:
A) reptiles.
B) whales and dolphins.
C) amphibians.
D) aquatic birds.
E) fish.

Back 39

amphibians.

Front 40

40) RNA molecules that function as enzymes:
A) form primitive cells.
B) degrade proteins.
C) are called ribozymes.
D) developed from protein-based enzymes.
E) duplicate lipid molecules.

Back 40

are called ribozymes.

Front 41

41) What is the relationship among DNA, a gene, and a chromosome?
A) A chromosome contains hundreds of genes, which are composed of DNA.
B) A chromosome contains hundreds of genes, which are composed of protein.
C) A gene contains hundreds of chromosomes, which are composed of protein.
D) A gene contains hundreds of chromosomes, which are composed of DNA.
E) A gene is composed of DNA, but it has no relationship to a chromosome.

Back 41

A chromosome contains hundreds of genes, which are composed of DNA.

Front 42

42) How many bases are in a codon?
A) 64
B) 3
C) 20
D) 4

Back 42

3

Front 43

43) Mutations are important because they:
A) usually provide an individual with increased reproductive rates.
B) provide variation that can result in evolutionary change.
C) are always beneficial in the individuals affected by them.
D) occur in response to environmental demands.

Back 43

provide variation that can result in evolutionary change.

Front 44

44) Each of your body cells:
A) is genetically identical to all others.
B) changes genetically as you grow and develop.
C) contains unique genetic information.
D) contains only the genetic information needed for that type of cell.

Back 44

is genetically identical to all others.

Front 45

45) The genetic code is:
A) used during the translation of DNA to mRNA.
B) read in sets of three bases called codons.
C) different in different organisms.
E) 46)

Back 45

read in sets of three bases called codons.

Front 46

46) If, in a heterozygous individual, only one allele is expressed in the phenotype, that allele is:
A) recessive.
B) normal.
C) potent.
D) dominant.
E) haploid.

Back 46

dominant.

Front 47

47) Probably the greatest advantage for the original multicellular organisms was their ability to:
A) use more oxygen.
B) photosynthesize.
C) increase their metabolism.
D) increase their food intake.
E) avoid predators.

Back 47

avoid predators.

Front 48

48) What is the ratio of phenotypes in the offspring produced by the cross Aa x Aa? Assume complete dominance for the trait.
A) 25% dominant:75% recessive
B) 100% recessive
C) 100% dominance
D) 50% dominant:50% recessive
E) 75% dominant:25% recessive

Back 48

75% dominant:25% recessive

Front 49

49) The sequence of nitrogen-containing bases on one strand of DNA most directly determines the sequence of:
A) bases in a protein molecule.
B) fatty acids in a fat molecule.
C) amino acids in a protein molecule.
D) sugars in a polysaccharide molecule.

Back 49

amino acids in a protein molecule.

Front 50

50) If the early Earth's atmosphere contained little or no O2, then where did most of the O2 in our modern atmosphere come from?
A) respiration
B) the oxidation of metals
C) the splitting of water vapor by sunlight
D) the breakdown of carbon dioxide
E) photosynthesis

Back 50

photosynthesis

Front 51

51) Which of the following is MOST likely to experience genetic drift?
A) a population of bears that is growing by thousands of individuals each year
B) a population of endangered birds that includes only five individuals
C) a plant species that has spread to many different habitats all around the world
D) a population of common rodents that includes millions of individuals
E) a species of insect that occurs all across North America

Back 51

a population of endangered birds that includes only five individuals

Front 52

52) If the sequence of bases in a section of DNA is TAGGCTAA, what is the corresponding sequence of bases in mRNA?
A) ATCCGATT
B) AUCCGAUU
C) AATCGGAT
D) TAGGCTAA
E) CGAAUCGG

Back 52

AUCCGAUU

Front 53

53) In the context of evolution, equilibrium means:
A) no individuals move into or out of the population.
B) no change in population size.
C) equal numbers of males and females.
D) equal numbers of all alleles.
E) no change in allele frequency.

Back 53

no change in allele frequency.

Front 54

54) By the early 1950s, many biologists realized that the key to understanding inheritance lay in the structure of:
A) enzymes.
B) chromosomes.
C) protein.
D) ribosomes.
E) DNA.

Back 54

DNA.

Front 55

55) The Kaibab squirrel lives on the north side of the Grand Canyon, and the Abert squirrel lives on the south side. Even though these two populations are only miles apart, their gene pools are kept isolated by:
A) temporal isolation.
B) mechanical incompatibility.
C) geographic isolation.
D) hybrid infertility.
E) ecological isolation.

Back 55

geographic isolation.

Front 56

56) When a cell divides via asexual reproduction:
A) each daughter cell receives a nearly perfect copy of the parent cell's genetic information.
B) each daughter cell receives the same amount of genetic information that was in the parent cell, but it has been altered.
C) the genetic information is randomly parceled out to the daughter cells.
D) each daughter cell receives exactly half the genetic information in the parent cell.

Back 56

each daughter cell receives a nearly perfect copy of the parent cell's genetic information.

Front 57

57) A change in the genetic makeup of a population is called:
A) evolution.
B) natural selection.
C) uniformitarianism.
D) artificial selection.

Back 57

evolution.

Front 58

58) The first multicellular terrestrial organisms were:
A) amphibians.
B) insects.
C) plants.
D) reptiles.
E) fungi.

Back 58

plants.

Front 59

59) Genetic inheritance is based on the "blueprint" of:
A) mRNA.
B) DNA.
C) enzymes.
D) proteins.

Back 59

DNA.

Front 60

60) The interaction of genes and environment produces a specific:
A) gene pool.
B) phenotype.
C) allele.
D) population.
E) genotype.

Back 60

phenotype.

Front 61

61) Natural selection is BEST described as:
A) the ability to generate new traits that better suit the species.
B) increasing the perfection of a species.
C) causing the death of a significant proportion of the population.
D) driving the species toward an eventual endpoint in which the species possesses the best possible adaptations for that particular environment.
E) working on the existing variation of traits to favor those better suited to the organism's environment.

Back 61

working on the existing variation of traits to favor those better suited to the organism's environment.

Front 62

62) During which phase of mitosis do the centromeres line up along the cell equator?
A) prophase
B) anaphase
C) telophase
D) metaphase

Back 62

metaphase

Front 63

63) Genetic variations in natural populations develop due to:
A) individual activities.
B) changes in diet.
C) environmental catastrophies.
D) random mutations of the DNA.
E) changes in the environment.

Back 63

random mutations of the DNA.

Front 64

64) Codominance occurs when:
A) offspring exhibit several different phenotypic expressions of a single trait.
B) expression of two different alleles alternates from one generation to the next.
C) both of the alleles in a heterozygote are expressed phenotypically in an individual.
D) a heterozygote expresses an intermediate phenotype.

Back 64

both of the alleles in a heterozygote are expressed phenotypically in an individual.

Front 65

65) Which of the following is the correct structure of a nucleotide?
A) phospholipid-base-sugar
B) base-sugar-base
C) phosphate-sugar-phosphate
D) phosphate-sugar-base

Back 65

phosphate-sugar-base

Front 66

66) The nitrogenous base uracil pairs with:
A) cytosine.
B) thymine.
C) uracil.
D) adenine.
E) guanine.

Back 66

adenine.

Front 67

67) Some RNA molecules have been discovered that can:
A) act as enzymes.
B) duplicate lipid molecules.
C) convert organic molecules to protocells.
D) degrade proteins.
E) form primitive cells.

Back 67

act as enzymes.

Front 68

68) The gene pool for a particular gene is made up of:
A) the sum of all the heterozygous individuals in the population.
B) the sum of all the homozygous individuals in the population.
C) all the alleles for a certain trait in a given individual.
D) all the genes that occur in the population.
E) all the genes for a certain trait that occur in the population.

Back 68

all the genes that occur in the population.

Front 69

69) For the DNA sequence G-C-C-T-A-T in one polynucleotide chain, the sequence found in the other polynucleotide chain must be:
A) G-C-C-A-T-A.
B) C-G-G-A-U-A.
C) G-C-C-T-A-T.
D) A-T-T-C-G-C.
E) C-G-G-A-T-A.

Back 69

C-G-G-A-T-A.

Front 70

70) DNA possesses:
A) C, T, A, and G bases.
B) A, U, G, and C bases.
C) both U and T bases.
D) only C and T bases.
E) only A and G bases.

Back 70

C, T, A, and G bases.

Front 71

71) The most common cause of extinction is:
A) limited species range.
B) habitat change.
C) interactions with other species.
D) overspecialization.
E) asteroid impacts.

Back 71

habitat change.

Front 72

72) In an equilibrium population:
A) natural selection occurs.
B) rates of gene flow are constant.
C) mutation rates do not change.
D) population size cannot change.
E) allele frequencies do not change.

Back 72

allele frequencies do not change.

Front 73

73) The two polynucleotide chains in a DNA molecule are attached to each other by:
A) peptide bonds between amino acids.
B) covalent bonds between phosphates and sugars.
C) ionic bonds between "R" groups in amino acids.
D) hydrogen bonds between bases.
E) covalent bonds between carbon atoms.

Back 73

hydrogen bonds between bases.

Front 74

74) During cell division, all of the following typically occur EXCEPT:
A) the hereditary information is identical in both parent and daughter cells.
B) each daughter contains half of the cytoplasm from the parent cell.
C) each daughter cell receives half of the hereditary information in the parent cell.
D) two daughter cells are produced from one parent cell.

Back 74

each daughter cell receives half of the hereditary information in the parent cell.

Front 75

75) The scientists usually given credit for disproving the theory of spontaneous generation of bacteria are:
A) Cech and Altman.
B) Oparin and Haldane.
C) Tyndall and Pasteur.
D) Miller and Urey.
E) Luis and Walter Alvarez.

Back 75

Tyndall and Pasteur.

Front 76

76) When the two gametes that fuse to form a zygote contain different alleles of a given gene, the offspring is:
A) haploid.
B) a new species.
C) homozygous.
D) heterozygous.
E) abnormal.

Back 76

heterozygous.

Front 77

77) Before the modern era of science, organisms were assigned to species on the basis of:
A) geographic location.
B) the existence of fossils of earlier forms.
C) behavioral similarities.
D) similarities in appearance.
E) their capability of interbreeding.

Back 77

similarities in appearance.

Front 78

78) Which of the following can cause evolutionary change in a small population?
A) lack of mutations
B) homozygous individuals
C) genetic drift
D) lack of gene flow
E) all recessive alleles

Back 78

genetic drift

Front 79

79) Two different species of pine release their pollen at different times. This is an example of:
A) behavioral isolation.
B) mechanical incompatibility.
C) geographic isolation.
D) ecological isolation.
E) temporal isolation.

Back 79

temporal isolation.

Front 80

80) Complementary base pairs are held together by:
A) hydrogen bonds.
B) covalent bonds.
C) peptide bonds.
D) ionic bonds.
E) disulfide bonds.

Back 80

hydrogen bonds.

Front 81

81) The process of copying genetic information from DNA to RNA is called:
A) replication.
B) transformation.
C) transcription.
D) translation.

Back 81

transcription.

Front 82

82) The oldest fossil organisms presently known have been dated at approximately how many years old?
A) 4.5 billion
B) 1.7 billion
C) more than 4.5 billion
D) less than 1.7 billion
E) 3.5 billion

Back 82

3.5 billion

Front 83

83) Both DNA and RNA:
A) are single-stranded molecules.
B) cannot be present in a cell simultaneously.
C) contain phosphate groups.
D) contain the same four types of nitrogen-containing bases.
E) have the same five-carbon sugars.

Back 83

contain phosphate groups.

Front 84

84) Fruit fly species all look similar to one another. If you have a male and a female fruit fly, how can you prove that they are the same species, according to the biological species concept?
A) If they mate successfully and their offspring are fertile, they are the same species.
B) Examine them closely with a low-power microscope, comparing their physical characteristics to published species key lists of characteristics.
C) Determine the base sequence of the DNA of their chromosomes.
D) If they can asexually reproduce and their offspring can also successfully asexually reproduce, they are the same species.
E) If they mate when they are put together, they are the same species.

Back 84

If they mate successfully and their offspring are fertile, they are the same species.

Front 85

85) All of the following statements about genotypes and phenotypes are true EXCEPT:
A) individuals with the same phenotype might have different genotypes.
B) matings between individuals with dominant phenotypes cannot produce offspring with recessive phenotypes.
C) individuals with the same genotype might have different phenotypes.
D) matings between individuals with recessive phenotypes usually do not produce offspring with dominant phenotypes.

Back 85

matings between individuals with dominant phenotypes cannot produce offspring with recessive phenotypes.

Front 86

86) When alleles move into different gametes, this demonstrates:
A) fertilization.
B) independent assortment.
C) dominance.
D) segregation.
E) crossing over.

Back 86

segregation.

Front 87

87) Which of the following statements about stem cells is TRUE?
A) They are able to differentiate into a variety of cell types.
B) They are "perpetual" parent cells that never produce daughter cells.
C) They are found only in embryos and in the bone marrow of adults.
D) They are found only in embryos.
E) They are permanently differentiated and cannot further divide.

Back 87

They are able to differentiate into a variety of cell types.

Front 88

88) The biological concept of species requires that:
A) individuals are able to reproduce outside the group.
B) geographic isolation occurs.
C) organisms are morphologically similar.
D) organisms reproduce sexually.
E) only asexual reproduction occurs.

Back 88

organisms reproduce sexually.

Front 89

89) Which organism is least likely to survive to reproduce?
A) a shrub that produces a toxin in its flower buds that repels deer
B) a plant that has a sweet flavor before it flowers
C) a dark-furred rodent that comes out only at night
D) a flower that produces a scent that attracts bees
E) a seahorse that mimics the weeds in which it lives

Back 89

a plant that has a sweet flavor before it flowers

Front 90

90) In a typical human body cell, how many chromosomes are there?
A) 23
B) 2
C) 1
D) 46

Back 90

46

Front 91

91) Which of the following is noted when comparing DNA and RNA?
A) Thymine pairs with different bases in DNA and RNA.
B) Only DNA has a backbone made up of sugars and phosphates.
C) Adenine pairs with different bases in DNA and RNA.
D) Hydrogen bonding is important only in DNA.
E) No sugar is present in either molecule.

Back 91

Adenine pairs with different bases in DNA and RNA.

Front 92

92) Which is the correct series of events in the evolution of life on Earth?
A) aerobic metabolism photosynthesis O2
B) photosynthesis O2 aerobic metabolism
C) O2 aerobic metabolism photosynthesis
D) O2 photosynthesis aerobic metabolism

Back 92

photosynthesis O2 aerobic metabolism

Front 93

93) According to the law of segregation:
A) pairs of alleles fuse during the formation of gametes.
B) pairs of alleles separate during the formation of gametes.
C) each individual carries a single copy of each "factor."
D) there is an independent assortment of nonhomologous chromosomes during meiosis.
E) the sex chromosomes of males and females differ.

Back 93

pairs of alleles separate during the formation of gametes.

Front 94

94) The earliest fossil organisms resemble modern:
A) eukaryotes.
B) protists.
C) protocells.
D) green algae.
E) prokaryotes.

Back 94

prokaryotes.

Front 95

95) How many consecutive mRNA bases are needed to specify an amino acid?
A) 3
B) 64
C) 20
D) 4

Back 95

3