320 Created by Master Student Biology Practice Test #9 1 / 40 A somatic cell of the common octopus (Octopus vulgaris) has 56 chromosomes. What number of chromosomes will an octopus gamete contain? 14 28 56 112 168 A somatic cell is diploid. If the organism's diploid chromosome number is 56, then the haploid gamete will possess half of this number of chromosomes, which is 2 2 / 40 As a reaction proceeds, reactants form a transition state, which then forms the products. An enzyme affects the energy of the products only reactants only transition state only products and reactants transition state and products An enzyme speeds up the rate of a reaction by lowering the activation energy, making the transition state less stable. It does not affect the energy of the products or the reactants. 3 / 40 An organism that demonstrates radial symmetry and an exoskeleton would be classified into which phylum? Arthropoda Cnidaria Echinodermata Mollusca Porifera The phyla Mollusca and Arthropoda do not exhibit radial symmetry; they are bilaterally symmetrical. Phylum Porifera demonstrates an asymmetrical body plan. Phylum Cnidaria does exhibit radial symmetry; however, this group lacks any skeletal form, leaving the only possible correct answer to be Echinodermata. 4 / 40 Which of the following indicates that animals have internal biological clocks? A mouse kept in constant darkness shows a daily rhythm of activity. A rooster crows whenever the sun rises in both winter and summer. An owl kept in constant light drifts away from a 24-hour cycle. Some species of birds can sense fluctuations in the Earth's magnetic field. A squirrel whose night and day are artificially reversed soon adapts to its new schedule. A If an organism's environment remains absolutely constant, and that organism still exhibits regular rhythms of activity, there must be some internal "clock" that keeps it on schedule (C and E are wrong). Roosters vary the time of their crow as the sun varies the time it rises (B is wrong). The magnetic field has nothing to do with internal clocks (D is wrong). 5 / 40 Tissue that conducts sugars downward from the leaves Xylem Phloem Cambium Bark Pith Phloem is the plant vascular tissue responsible for conducting water and dissolved sugars throughout the plant, downward from the leaves. It is always exterior to xylem, from which it is separated by the vascular cambium. 6 / 40 This is required for speciation to occur. Founder effect Heterozygote advantage Population bottleneck Random mating Reproductive isolation Speciation requires that two populations be reproductively isolated from each other, allowing natural selection to act independently on each. 7 / 40 An organism produces many offspring each reproductive season, only a few of which survive. The survivorship curve for this organism can BEST be described as closely matching curve 1 closely matching curve 2 closely matching curve 3 fitting between curves 1 and 2 fitting between curves 2 and 3 A type III survivorship curve indicates an organism that produces many offspring, many of which do not survive over time. A type II curve represents organisms that produce several offspring, a decent proportion of which survive over time. A type I curve represents an organism that produces very few offspring, most of which survive over time. 8 / 40 Crabs and lobsters are both members of the suborder Pleocyemata. Both possess a tail; however, in the crab, this structure is very small and not used. This structure can be considered an example of all of the following EXCEPT convergent evolution vestigial structure divergent evolution genetic fitness homologous structure Convergent evolution occurs when two unrelated species over time adapt the same structure. This is the reverse of what has occurred with tails in lobsters and crabs. An unused evolutionary relic can be termed a vestigial structure and also a homologous structure. This is an example of divergent evolution, where close relatives have begun to adapt differently from one another. 9 / 40 Human immunodeficiency virus (HIV) is a retrovirus that integrates its own DNA into a host cell's genome using DNA polymerase helicase primase ligase reverse transcriptase Reverse transcriptase is an enzyme used to transcribe RNA sequences to DNA sequences. Its function is the reverse of the transcriptase that produces mRNA from DNA. 10 / 40 The steps of protein synthesis and modification take place in several different locations throughout the cell. What is the proper order of these locations, from start to finish? I. Ribosome II. Nucleus III. Golgi apparatus IV. Endoplasmic reticulum I, II, III, IV II, I, IV, III III, II, IV, I II, I, III, IV IV, III, II, I 0 11 / 40 Geese recognize a ticking clock as "mother" if exposed to it during a critical period shortly after hatching Reasoning/insight Imprinting Classical conditioning Habituation Instinct B Some animals do not have an instinctive sense for who their mother is and will bond with any object they are exposed to during a certain time period after their birth. The object "imprints" on their minds, and thereafter, even if exposed to their real mother, they will still treat the object as Mom. 12 / 40 Which structure releases hormones that signal the tissue lining the uterus to thicken? Corpus luteum Developing follicle Fallopian tube Hypothalamus Pituitary The corpus luteum, which forms after an egg is released from a follicle in the ovary, secretes estrogen and progesterone. These hormones cause the uterine lining to thicken. If a fertilized egg does not implant, the corpus luteum shrivels and the uterine lining is shed. 13 / 40 Which of the following characteristics of an allele is required for it to increase in a population through natural selection? Individuals with the allele are better able to find food. Individuals with the allele are better able to resist disease. Individuals with the allele have an increased ability to find and retain mates. Individuals with the allele produce more offspring that reach adulthood. Individuals with the allele have a longer lifespan than those without it. In order for an allele to be acted on by natural selection, it must result in an increase in fitness. Fitness is defined as the ability to pass traits on to offspring. Therefore, individuals that produce the greatest number of offspring that grow to become fertile adults have the greatest fitness. 14 / 40 Which biome contains maples, squirrels, and black bears? Tundra Tropical rain forest Temperate grasslands Taiga Deciduous forest E Maples are deciduous trees (they lose their leaves); this is the best tip-off for choice E. You should be able to eliminate choice A (tundra has only small shrubby plants) and choice D (taiga is coniferous forest) easily. Tropical rain forest (choice B) and temperate grasslands (choice C) do not have black bears. 15 / 40 Which describes the cause of eutrophication in lakes? A lack of oxygen A lack of sunlight A lack of nutrients An excess of oxygen An excess of nutrients Eutrophication, or the growth of algae, is caused by an excess of dissolved nutrients. The source of these nutrients is often agricultural or residential runoff. 16 / 40 Which of these form the basis of natural selection? I. Random mating II. Limited environmental resources III. Stable genotype frequencies over time I only II only III only I and II II and III 0 17 / 40 A population of birds lives in an area with many insects upon which it feeds. The insects live inside trees, burrowing into the bark. Over many hundreds of years, the average beak size in the bird population has increased. This is due to increased fitness of the birds, leading to speciation decreased fitness of the insects, allowing the birds to catch them more easily increased fitness of large-beaked birds, leading to evolution decreased fitness of small-beaked birds, leading to speciation random mutation and genetic recombination C A change in a population that occurs over a long period of time is evolution. This alone is a good tip-off that choice C, the only choice that mentions evolution, is correct. Speciation has not occurred, only a change in the characteristic of the birds, thus choices A and D can be eliminated. Any change in the fitness of the insects would change the characteristics of the insect population, not the bird population (B is wrong), and random mutation would not produce a specific, directed effect (E is wrong). Birds with large beaks had greater fitness because they could more easily obtain food, thus they had an advantage over birds with smaller beaks, which died out as time passed. 18 / 40 Which of these mutations in a gene will MOST LIKELY result in a shortened protein with a long sequence of substituted amino acids? Missense substitution of one nucleotide Insertion of two nucleotides Deletion of three nucleotides Silent substitution of four nucleotides Nonsense substitution of five nucleotides The insertion of two nucleotides will shift the reading frame of all the codons "downstream" of the mutation, resulting in a series of mis-sense codons and eventually a nonsense (stop) codon. 19 / 40 A barren, rocky community near a lake has virtually no vegetation or animal life. After a period of approximately 75 years, the community boasts a wide variety of flora and fauna, including deciduous trees, deer, and raccoon. Usually the first organisms to colonize rocky areas are lichen. These are known as the primary community starter community colony organisms pioneer organisms settler organisms D The first organisms to colonize a barren area are known as the pioneer organisms. 20 / 40 Which of these does NOT secrete any digestive enzyme? Salivary glands Liver Pancreas Small intestine Stomach The liver secretes lipase, which emulsifies fats and allows them to be digested by pancreatic lipase. However, the liver does not produce digestive enzymes. 21 / 40 At some point in their development, chordates possess all of the following EXCEPT a dorsal hollow nerve cord a notochord gill slits postanal tail an exoskeleton E Remember your LEAST/EXCEPT/NOT technique. There are four features present in all chordates-dorsal nerve cords (choice A), notochords (choice B), gill slits (choice C), and postanal tails (choice D). Note that some of these features may be found only in embryonic or larval stages. The "wrong" answer is choice E-not all chordates (for example, sea squirts and lancelets) have a bony endoskeleton. 22 / 40 Biome characterized by great diversity of flora and fauna and high levels of precipitation Tundra Taiga Tropical rain forest Deciduous forest Desert C These are the characteristics of tropical rain forest. 23 / 40 In a tropical food web, 800,000 kJ of energy are produced by autotrophic species. Approximately how much energy will exist at the level of secondary consumers? 80 kJ 800 kJ 8,000 kJ 80,000 kJ 800,000 kJ In a trophic pyramid, primary producers form the base, creating all the energy that will travel up through the pyramid. Just above the producers are primary consumers, which are herbivores that obtain all their energy directly from producers. To obtain that energy also requires energy, and so the amount of energy created by producers is not the same amount that moves up. Approximately 10% of energy is lost for every move up the pyramid, so in this example for the 800,000 kJ of energy produced, only 80,000 kJ will be present for primary consumers, the next level. Secondary consumers are the next level up, feeding on primary consumers, so another 10% of that level's energy will be lost, putting 8,000 kJ at this trophic level. 24 / 40 This nucleic acid carries genetic information to the site of translation. DNA mRNA rRNA snRNA tRNA The nucleic acid in mRNA carries genetic information from the nucleus to the ribosomes in the cytoplasm, where it is translated into a polypeptide. 25 / 40 A unicellular organism contains a Golgi body and ribosomes but lacks a cell wall. It is heterotrophic, ingesting food via phagocytosis. What kingdom does this organism belong to? Animalia Eubacteria Fungi Protista Archaea Protists include unicellular, eukaryotic organisms that digest food inside the cell. (Fungi, in contrast, carry out extracellular digestion.) 26 / 40 During mitosis, a checkpoint ensures that all chromosomal kinetochore proteins, present at the centromere of each sister chromatid, are attached to spindle fibers. Kinetochore proteins that are unattached produce a signal that prevents mitosis from proceeding to the next stage. This checkpoint occurs at the transition from anaphase to telophase prophase to metaphase metaphase to telophase prophase to anaphase metaphase to anaphase Sister chromatids line up at the metaphase plate, and spindle fibers attach to kinetochore proteins at the centromeres. All sister chromatids must be present and attached to spindle fibers in order to prevent nondisjunction during anaphase. An unattached kinetochore protein generates a signal that prevents the transition from metaphase to anaphase. 27 / 40 What is the role of mRNA in protein synthesis? To make up the structure of the ribosome To carry amino acids to the ribosome To catalyze bonds between nucleotides To serve as a template for the synthesis of DNA To carry information determining amino acid sequence During transcription, an mRNA transcript is copied from a DNA template. This transcript transports genetic information out of the nucleus. 28 / 40 Which of these releases carbon dioxide? I. Lactic acid fermentation II. Alcohol fermentation III. Aerobic respiration IV. Photosynthesis I and II I and III II and III II and IV III and IV 0 29 / 40 Transports amino acids during protein synthesis DNA tRNA mRNA rRNA RNA polymerase B You should again be able to eliminate choices E and A, as above. The type of RNA that carries amino acids is tRNA. Remember t for "transport." 30 / 40 A researcher has a black guinea pig and wishes to determine if it carries a recessive allele for white hair. Both of the guinea pig's parents are black. Which of the following would be the best method for the researcher to use? Mate the guinea pig with a white guinea pig and look for white offspring Observe the chromosomes of a hair cell from a black hair See if the guinea pig has any white siblings Mate the guinea pig with another black guinea pig and look for white offspring Look for white hairs on the guinea pig C Whenever you're trying to determine the genotype of an organism that has a dominant phenotype, the best thing to do is something called a test cross. A test cross is a mating between the organism with the unknown genotype and an organism with the recessive phenotype. (Organisms that display the recessive phenotype MUST have the homozygous recessive genotype; the genotype of this organism is known.) Then, you just look at the offspring produced. If the organism with the unknown genotype were homozygous dominant, all the offspring would have the dominant phenotype. If, however, the organism with the unknown genotype were heterozygous, half the offspring would have the dominant phenotype and half would have the recessive phenotype. Look at the two possible Punnett squares: 31 / 40 In the Oparin-Haldane experiment, the artificial atmosphere they created contained which of the following? I. Hydrogen gas II. Oxygen gas III. Reducing gases I only II only I and II I and III II and III 0 32 / 40 This organ secretes a hormone that causes the liver to break down glycogen. Thyroid Pancreas Parathyroid Adrenal medulla Anterior pituitary The pancreas secretes glucagon in response to low blood glucose levels. This causes the liver to release glucose into the bloodstream. 33 / 40 Edward's syndrome is the result of an additional 18th chromosome present in a fertilized embryo. Which of the following events could lead to the presence of this additional chromosome in a zygote? Crossing over in meiosis I Nondisjunction in meiosis II A deletion during meiosis II A deletion during meiosis I Replication error in meiosis II Nondisjunction occurs when two homologous chromosomes or chromatids fail to segregate; if this were to occur in meiosis I or II, the resulting zygote could have three copies of a chromosome. 34 / 40 A genetic mutation results in a DNA sequence that continues to synthesize the same protein, at the same rate as a nonmutated sequence. This mutation would be BEST classified as a deletion insertion missense mutation nonsense mutation silent mutation A silent mutation is not phenotypically visible because the protein product remains unchanged. 35 / 40 Semelparous species produce a large number of offspring once in their life spans. Iteroparous species produce a small number of offspring repeatedly throughout their lives. Which ecological condition will most likely select for a semelparous strategy? A surplus of nutrients or food sources A lack of competition from other species The availability of multiple ecological niches Persistent limiting factors in the environment A lack of consistency of environmental conditions A lack of consistency in environmental conditions will favor semelparity. The offspring's genetic variation ensures that at least some will survive the changing conditions. 36 / 40 The loop of Henle is a structure within the urinary tract responsible for reabsorbing water. Compared to a terrestrial species, how might this structure appear in a freshwater aquatic species? Absent Longer Shorter Withered Thinner Freshwater aquatic animals require less ability to reabsorb water than do terrestrial or saltwater species, which require a greater capacity for water reabsorption and thus a longer loop of Henle. 37 / 40 How do enzymes help to carry out biochemical reactions? By decreasing the energy of the reactants By increasing the activation energy of the reaction By decreasing the activation energy of the reaction By increasing the energy of the products of the reaction By decreasing the energy of the products of the reaction Enzymes decrease the activation energy required for a chemical reaction to take place, allowing a reaction to proceed without a large energy input and thereby greatly increasing the reaction rate. 38 / 40 What is the role of mRNA in protein synthesis? To make up the structure of the ribosome To carry amino acids to the ribosome To catalyze bonds between nucleotides To serve as a template for the synthesis of DNA To carry information determining amino acid sequence During transcription, an mRNA transcript is copied from a DNA template. This transcript transports genetic information out of the nucleus. 39 / 40 Pepsinogen is secreted by the cells lining the stomach. In a low-pH solution, it is converted to an active enzyme, called pepsin. The purpose of producing pepsinogen instead of pepsin is to preserve the active site protect the secreting cells raise the pH of the liquid inside the stomach ensure that the enzyme is active when food is present prevent the enzyme from breaking down carbohydrate Pepsin is an enzyme that digests protein in the stomach. It is produced by cells as an inactive precursor to avoid damaging the proteins within the cells. 40 / 40 A human hereditary disorder that is present only in males is most likely maternally inherited a Y-linked trait an autosomal recessive trait an X-linked recessive trait an X-linked dominant trait A disorder that is only found in males must be Y linked. An X-linked trait would occur in a small proportion of females. Your score is The average score is 63% LinkedIn Facebook Twitter VKontakte 0% Restart quiz Previous Quiz Next Quiz
