Biology Practice Test 4|50 Questions with Verified Answers,100% CORRECT, Exams of Nursing

Download Biology Practice Test 4|50 Questions with Verified Answers,100% CORRECT and more Exams Nursing in PDF only on Docsity! Biology Practice Test 4|50 Questions with Verified Answers 1) Which of the following is the best modern definition of evolution? A) descent with modification B) change in the number of genes in a population over time C) survival of the fittest D) inheritance of acquired characters - CORRECT ANSWER A 2) Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true? A) Each bird evolved a deeper, stronger beak as the drought persisted. B) Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted. C) Each bird that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation. D) The frequency of the strong-beak alleles increased in each bird as the drought persisted. - CORRECT ANSWER B 3) Genetic variation _____. A) is created by the direct action of natural selection B) arises in response to changes in the environment C) must be present in a population before natural selection can act upon the population D) tends to be reduced by when diploid organisms produce gametes - CORRECT ANSWER C 4) Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during the teenage years. If 9 in 10,000 newborn babies have the disease, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the Hardy-Weinberg model? A) f(A1) = 0.9997, f(A2) = 0.0003 B) f(A1) = 0.9800, f(A2) = 0.0200 C) f(A1) = 0.9700, f(A2) = 0.0300 D) f(A1) = 0.9604, f(A2) = 0.0392 - CORRECT ANSWER C 5) In the formula for determining a population's genotype frequencies, the "2" in the term 2pq is necessary because _____. A) the population is diploid B) heterozygotes can come about in two ways C) the population is doubling in number D) heterozygotes have two alleles - CORRECT ANSWER B 6) An earthquake decimates a ground-squirrel population, killing 98% of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake? A) directional selection B) disruptive selection C) a founder event D) a genetic bottleneck - CORRECT ANSWER D 7) The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid-1700s. They do not marry with members outside their own immediate community. Today, the Dunkers are genetically unique and differ in gene frequencies, at many loci, from all other populations including those in their original homeland. Which of the following likely explains the genetic uniqueness of this population? A) population bottleneck and Hardy-Weinberg equilibrium B) heterozygote advantage and stabilizing selection C) mutation and natural selection D) founder effect and genetic drift - CORRECT ANSWER D 8) Which of the following is the most predictable outcome of increased gene flow between two populations? A) lower average fitness in both populations B) higher average fitness in both populations C) increased genetic difference between the two populations D) decreased genetic difference between the two populations - CORRECT ANSWER D 9) Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing _____. C) Base pairings create unequal spacing between the two DNA strands. D) One strand contains only purines and the other contains only pyrimidines. - CORRECT ANSWER B 18) In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation? A) Additional proofreading will occur. B) No replication fork will be formed. C) Replication will occur via RNA polymerase alone. D) Replication will require a DNA template from another source - CORRECT ANSWER B 19) In E. coli, which enzyme catalyzes the elongation of a new DNA strand in the → direction? A) primase B) DNA ligase C) DNA polymerase III D) helicase - CORRECT ANSWER C 20) A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is _____. A) UCA B) UGA C) TCA D) ACU - CORRECT ANSWER A 21) The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following? A) A gene from an organism can theoretically be expressed by any other organism. B) DNA was the first genetic material. C) The same codons in different organisms translate into different amino acids. D) Different organisms have different types of amino acids. - CORRECT ANSWER A 22) In the process of transcription, _____. A) DNA is replicated B) RNA is synthesized C) proteins are synthesized D) mRNA attaches to ribosomes - CORRECT ANSWER B 23) Codons are part of the molecular structure of _____. A) a protein B) mRNA C) tRNA D) rRNA - CORRECT ANSWER B 24) Which of the following occurs in prokaryotes but not in eukaryotes? A) post-transcriptional splicing B) concurrent transcription and translation C) translation in the absence of a ribosome D) gene regulation - CORRECT ANSWER B 25) Which of the following statements best describes the termination of transcription in prokaryotes? A) RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase. B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript. C) Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome. D) RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA. - CORRECT ANSWER B 26) Transcription in eukaryotes requires which of the following in addition to RNA polymerase? A) start and stop codons B) ribosomes and tRNA C) several transcription factors D) aminoacyl-tRNA synthetase - CORRECT ANSWER C 27) A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is _____. A) TTT B) UUA C) UUU D) AAA - CORRECT ANSWER D 28) Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the _____. A) binding of ribosomes to mRNA B) binding of the anticodon to small subunit of the ribosome C) attachment of amino acids to rRNAs D) binding of the anticodon to the codon and the attachment of amino acids to tRNAs - CORRECT ANSWER D 29) A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that _____. A) none of the proteins in the cell will contain phenylalanine B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU C) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons D) the ribosome will skip a codon every time a UUU is encountered - CORRECT ANSWER B 30) Which of the following is a protein produced by a regulatory gene? A) operon B) inducer C) promoter D) repressor - CORRECT ANSWER D 31) A lack of which molecule would result in a cell's inability to "turn off" genes? A) operon B) inducer C) promoter D) corepressor - CORRECT ANSWER D 32) Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation? B) Their DNA does not encode proteins. C) They have RNA rather than DNA. D) They do not evolve. - CORRECT ANSWER A 43) Viruses _____. A) manufacture their own ATP, proteins, and nucleic acids B) use the host cell to copy themselves and make viral proteins C) use the host cell to copy themselves and then viruses synthesize their own proteins D) metabolize food and produce their own ATP - CORRECT ANSWER B 44) What is the main structural difference between enveloped and nonenveloped viruses? A) Enveloped viruses have their genetic material enclosed by a layer made only of protein. B) Nonenveloped viruses have only a phospholipid membrane, while enveloped viruses have two membranes, the other one being a protein capsid. C) Enveloped viruses have a phospholipid membrane outside their capsid, whereas nonenveloped viruses do not have a phospholipid membrane. D) Both types of viruses have a capsid and phospholipid membrane; but in the nonenveloped virus the genetic material is between these two membranes, while in the enveloped virus the genetic material is inside both membranes. - CORRECT ANSWER C 45) The host range of a virus is determined by _____. A) the enzymes carried by the virus B) whether its nucleic acid is DNA or RNA C) the proteins in the host's cytoplasm D) the proteins on its surface and that of the host - CORRECT ANSWER D 46) In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following would you expect of the genes of a bacteriophage? A) regulation via acetylation of histones B) positive control mechanisms rather than negative C) control of more than one gene in an operon D) reliance on transcription activators - CORRECT ANSWER C 47) What is the function of reverse transcriptase in retroviruses? A) It uses viral RNA as a template for DNA synthesis. B) It converts host cell RNA into viral DNA. C) It translates viral RNA into proteins. D) It uses viral RNA as a template for making complementary RNA strands - CORRECT ANSWER A 48) HIV is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. What are the practical consequences of these findings? A) HIV can be transmitted more easily from person to person than the flu virus B) The flu virus can be transmitted more easily from person to person than HIV C) This property of HIV makes it more likely to be a pandemic than the flu virus D) Disinfecting surfaces is more important to reduce the spread of HIV than the flu - CORRECT ANSWER B 49) Why do RNA viruses appear to have higher rates of mutation? A) RNA nucleotides are more unstable than DNA nucleotides. B) Replication of their genomes does not involve proofreading. C) RNA viruses can incorporate a variety of nonstandard bases. D) RNA viruses are more sensitive to mutagens. - CORRECT ANSWER B 50) Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell? A) herpes B) HIV C) smallpox D) influenza . - CORRECT ANSWER B