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Genetics Final Exam

Questions & Correct Solutions

Genetics Final Exam

Questions & Correct

Solutions(GRADED A)

Gregor Mendel was: a) an English scientist who carried out research with Charles Darwin b) a little known Central European monk c) an early 20th century Dutch biologist who carried out genetics research - ANSWER B Which of the following statements is true about Mendel? a) His discoveries concerning genetic inheritance were generally accepted by the scientific community when he published them during the mid 19th century. b) He believed that genetic traits of parents will usually blend in their children. c) His ideas about genetics apply equally to plants and animals. - ANSWER C Mendel believed that the characteristics of pea plants are determined by the: a) inheritance of units or factors from both parents b) inheritance of units or factors from one parent c) relative health of the parent plants at the time of pollination - ANSWER A An allele is: a) another word for a gene b) a homozygous genotype c) a heterozygous genotype d) one of several possible forms of a gene - ANSWER D Phenotype refers to the ______________________ of an individual. a) genetic makeup b) actual physical appearance c) recessive alleles - ANSWER B When the genotype consists of a dominant and a recessive allele, the phenotype will be like _________________ allele.

a) the dominant b) the recessive c) neither - ANSWER A Assuming that both parent plants in the diagram below are homozygous, why would all of the f generation have yellow phenotypes? Help Getting Started diagram showing the result of cross-pollination in the first 2 offspring generations--in generation f1 all are yellow peas but in generation f2 the ratio of yellow to green peas is 3 to 1 a) because the f1 genotypes are homozygous b) because yellow is dominant over green c) because both parents passed on yellow alleles - ANSWER B The idea that different pairs of alleles are passed to offspring independently is Mendel's principle of: a) unit inheritance b) segregation c) independent assortment - ANSWER C In the diagram below, what accounts for the green pea seed in the f2 generation? Help Getting Started diagram showing the result of cross-pollination in the first 2 offspring generations--in generation f1 all are yellow peas but in generation f2 the ratio of yellow to green peas is 3 to 1 a) On average, 1 out of 4 offspring of heterozygous parents will be homozygous recessive. b) The yellow allele is dominant over the green one. c) The f1 generation parents are homozygous yellow. - ANSWER A If and individual is affected by a rare recessive trait, what likely occurred for this to happen? A) Something went wrong when the egg and sperm connected B) The affected individual is the product of a consanguineous mating

C) It was already a trait in the ancestor line D) None of that person's ancestors displayed the same trait E) Both B and D - ANSWER E If an individual is affected by a rare dominant trait_________. A) The trait should also affect at least one of that person's parents, one grandparent, and so on B) It only should affect one of the parents C) It only should affect one grandparent D) It doesn't affect anyone else in the generation line - ANSWER A Which of the following describe epistasis A. Whenever two or more loci interact to create new phenotypes B. Whenever an allele at one locus masks the effects of alleles at one or more other loci C. Whenever an allele at one locus modifies the effects of alleles at one or more other loci D. All of the above - ANSWER D Pairing of homologous chromosomes occurs in _____? A. Mitosis B. Meiosis C. Both A and B D. Neither A or B - ANSWER B The process of establishing the locations of genes on chromosomes is called? A. Linkage B. Mosaic C. Recombination D. Gene mapping - ANSWER D What are bacteriophages? - ANSWER viruses that infect bacterial cells

What bases are Purines and Pyrimidines and what is the difference between the two? - ANSWER Purines: Adenine & Guanine Pyrimidines: Thymine & Cytosine & Uracil ( in RNA ) Purine: a nitrogenous base containing a double ring Pyrimidine: a nitrogenous base containing only one ring Which of the following step in DNA replication is wrong? a. Unwinding of the double helix. b. Each strand acts as a template for synthesis of new strands. c. New strands form by insertio of complementary base pairs d. Enzymes link sugar-phosphate elements of aligned nucleotides into a discontinuous new strand e. Single double helix becomes two identical daughter double helixes. - ANSWER D The idea that for any particular trait, the pair of alleles of each parent separate and only one allele from each parent passes to an offspring is Mendel's principle of: a) independent assortment b) hybridization c) segregation - ANSWER C Two identical parental generations with a yellow smooth phenotype are crossed. The offspring include the following phenotypes: yellow smooth, yellow wrinkled, green smooth, and green wrinkled. This is an example of? a. a monohybrid cross b. a pure-breeding line c. a recombinant type d. a late-onset condition e. Quadhybrid cross - ANSWER C What are the two basic rules of probability? A) The Product Rule

B) The Law of Segregation C) The Sum Rule D) Both A and B E) All of the above - ANSWER D Which explains the Law of Independent assortment? A) Mating between the F1 progeny of true-breeding parents that differed in three or more unrelated traits B) During gamete formation, different pairs of articles segregate independently of each other C) The random distribution of different genes during gamete formation D) The genetic engineering technique that modifies the DNA of germ cells that are passed on to progeny

• ANSWER B What two tools are considered to be a more efficient method of the analysis of genetic crossing that involves two or more genes? A) Punnett Square and Branched-line diagrams B) Direct calculation of probabilities and Punnett squares C) Branched-line diagrams and Direct Calculation of probabilities D) None of the above - ANSWER C What are Complementary base pairs? - ANSWER two nitrogenous bases that can pair via hydrogen bond. What does DNA polymerase do? - ANSWER catalyzes new phosphodiester bonds In what direction does DNA synthesis proceed? - ANSWER 5'-3' What does DNA polymerase III do? - ANSWER catalyzes phosphodiester bond formation between adjacent nucleotides. What is a Leading Strand? - ANSWER the stand that is synthesized continuously during replication.

What is the correct pairing of nitrogenous bases in DNA? A. A to G, T to C B. A to C, T to G C. A to T, G to C D. none of the above - ANSWER C What strand is replicated continuously during DNA replication? A. leading strand B. Okazaki fragments C. lagging strand D. continuous strand - ANSWER A Which enzyme is responsible for the addition of nucleotides when forming a new DNA strand? A. RNA Polymerase B. DNA Ligase C. DNA Polymerase I D. DNA Polymerase III - ANSWER D In the semiconservative model of DNA replication: A. one of the two "daughter" double helixes consists entirely of original DNA strands. B. one strand of each new double helix is conserved from the parent molecule and the other is newly synthesized C. both "daughter" double helixes carry blocks of original DNA interspersed with blocks of newly synthesized material. D. both "daughter" double helixes consist of entirely newly synthesized DNA. - ANSWER B What are two different types of mutations? - ANSWER Forward mutation and reverse mutation (reversion)

Which of the following is not a classification of a mutation? a. Inversion b. Deletion c. Substituion d. Elimination - ANSWER D The removal of an amino group (-NH2) from normal DNA: a. Depurination b. Translocation c. Deamination d. Elimination - ANSWER C Which of the following is NOT a DNA repair mechanism? a. Nucleotide excision repair b. Methyl-directed mismatch repair c. Amine excision repair d. Base excision repair - ANSWER C What test reveals whether two mutations are in a single gene or in different genes? a. Fluctuation test b. Complementation test c. Ames Test d. Mutagen test - ANSWER B When parts of two non-homologous chromosomes change places. a. Reciprocal translocations b. Rearrangements c. Forward mutation d. Inversion - ANSWER A

Which DNA repair mechanism corrects DNA replication errors and is known as the backup repair system? a. Nucleotide excision repair b. Base excision repair c. Methyl-directed mismatch repair d. SOS system - ANSWER C Cells can restitch the ends formed by double strand breaks using a mechanism called: a. Crossing-over b. Nonhomologous end-joining c. Substitutions d. Insertions - ANSWER B Transition Mutation is A) block of 1 or more bp lost from DNA B) purine replaced by another purine, or pyrimidine replaced by another pyrimidine C) purine replaced by a pyrimidine, or pyrimidine replaced by a purine D) block of 1 or more bp added to DNA - ANSWER B A Deletion is A) a block of 1 or more bp lost from DNA B) block of 1 or more bp added to DNA C) 180° rotation of a segment of DNA D) replacement of a base by another base - ANSWER A Which is not true of SOS in bacteria? A.Used at replication forks that stalled because of unrepaired DNA damage B.DNA polymerase uses normal polymerase

C.Adds random nucleotides opposite damaged bases D."Sloppy" DNA polymerase used instead of normal polymerase - ANSWER B Which of the following is NOT a type of mutation? A. Insertion B. Inversion C. Substitution D. Deamination - ANSWER D Which statement is true of homologous chromosomes? A. Unequal crossing over can occur between homologous chromosomes B.Pairing between homologs during meiosis can be out of register C. Unequal crossing-over results in a deletion on one homolog and a duplication on the other homolog D. All the statements above are true - ANSWER D Which are the mechanisms of Transposable element movement? A. Copy of TE is made B. No Copy of TE is made C. Both A & B D. None of the above are true - ANSWER C "Mutations can be classified into three categories, which of the following is not one of those categories?" A. Frameshift B. Sense C. Non-sense D. All of the above - ANSWER D A codon consists of:

a. A nitrogenous base, five-carbon sugar, and a phosphate group b. A chain of polypeptides c. A sequence of three nucleotides read in a defined reading frame d. DNA transcripted into RNA - ANSWER C A frame shift mutation: a. Alters the reading frame after an insertion or deletion of a nucleotide b. Alters the reading frame before an insertion or deletion of a nucleotide c. Has no affect on the reading frame d. Is also known as a missense mutation - ANSWER A Which of the following is not a way a mutation can be created? a. Nonsense b. Missense c. Frameshift d. Degeneration - ANSWER D RNA polymerase adds nucleotides in what direction? a. 3' to 5' b. 5' to 3' c. RNA polymerase doesn't add nucleotides in a sequence d. Both a and b - ANSWER B What is transcription? a. Building an RNA strand from a DNA strand b. Building an amino acid chain from reading RNA nucleotide sequences c. The first step in the PCR process d. None of the above - ANSWER A

Which of the following is not true of gene expression in eukaryotes? a. Initiator tRNA carries methionine b. Small ribosomal subunit binds first to the methylated cap at the 5' end of the mature mRNA and then scans the mRNA to find the ribosome binding site c. mRNAs have only one start site and can thus direct the synthesis of only one kind of polypeptide d. Genes are not divided into introns and exons - ANSWER D What is a Lagging Strand? - ANSWER the strand that is synthesized discontinuously during replication. What are Okazaki fragments? - ANSWER Short DNA fragments formed by discontinuous replication on the lagging strand. What does DNA polymerase I do? - ANSWER It replaces RNA primer with DNA sequence. What does DNA ligase do? - ANSWER It convalently joins successive Okazaki fragments together. What is Supercoiling? - ANSWER The additional twisting of the DNA molecule to make it tighter and more compact. What are DNA topoisomerases and what do they do? - ANSWER are a group of enzymes that help relax the supercoils by nicking one or both strands of DNA - cutting the sugar-phosphate boackbone between two adjoining nucleotides. Step 1 in Recombination: Double-strand break formation is? - ANSWER Dmc 1: breaks phosphodiester bonds of both strands of one chromatid. Step 2 in Recombination is? - ANSWER 5' end of each broken strand are degraded to create 3' single- stranded tails Step 3 in Recombination is? - ANSWER Displacement Loop (D-loop): from invaded chromatid is stabilized by single-stranded binding protein

Step 4 in Recombination is? - ANSWER - D-loop is enlarged by the new DNA synthesis at the 3'-end of the invading strand -New DNA synthesis fills in the gap in the bottom strand using displaced strand as template. What type of bond joins one nucleotide to another in one DNA strand? A. Hydrogen bonds B. phosphodiester bonds C. ionic bonds D. nucleic bonds - ANSWER B In the field of genetics, what is a SNP? A. Single Nucleotide Polymorphism B. Signal Nucleotide Polymorphism C. Single Nucleotide Polymer D. Spray and Neuter Program - ANSWER A In gel electrophoresis of DNA, fragments move at different rates because they have different A. charge densities. B. sizes. C. base sequences. D. amino acid compositions. E. electrical strengths. - ANSWER B PCR is used to A. generate DNA fragments for genomic libraries. B. generate DNA fragments for cDNA libraries. C. determine the sequence of a DNA fragment by the Maxam-Gilbert procedure. D. amplify minute quantities of a DNA fragment.

E. replicate recombinant plasmids. - ANSWER D Restriction enzymes were named because they restrict A. the capacity for viral growth. B. the growth of the bacteria that produces them. C. bacterial translation. D. bacterial transformation. E. bacterial transcription - ANSWER A A contig is: a) a map of genetic markers that separated by less than 1cM. b) a map showing the order of cloned bits of DNA. c) unique DNA sequences that serve as molecular markers. d) sets of two or more partially overlapping cloned DNA fragments. - ANSWER D Genes encode: A) noncoding RNAs B) Proteins C) both a and c D) none of the above - ANSWER C The population of mRNA expressed in a single cell or cell type is called: a) transcriptome b) genome c) proteome d) Spliceosom - ANSWER A Noncoding RNAs include: A) tRNAs

B) rRNAs C) snoRNAs D) snRNAs E) all of the above. F) only a, b, and c. - ANSWER E Which of the following is least similar between mouse and man A. synteny B. karyotype C. orthologous order D. genes - ANSWER B A DNA sequence can be useful for A. finding differences between individuals. B. finding information about protein function. C. finding protein motifs. D. finding duplicated genes. E. All of the above choices. - ANSWER E What is the relationship between genome size and number of genes compared between worms and humans? A. The number of genes will increase directly with the genome size. B. The number of genes remains the same regardless of the genome size. C. The genome size remains the same regardless of the number of genes. D. As genome size increases, the number of genes will only slightly increase E. As the number of genes increases, the genome size will only slightly increase. - ANSWER D When creating a karyotype, the autosomes are ordered in descending length. The short arm is known as "p", and the long arm is called

A. "x". B. "y". C. "a". D. "q". - ANSWER D Why would a hierarchical shotgun sequencing researcher use large inserts of DNA that are more likely to include errors when building a BAC library? A. The large pieces allow the researcher to correctly order the DNA inserts. B. Accuracy does not matter when creating a BAC library. C. The BAC library is only functional with large inserts. - ANSWER A What is the difference between a paralog and an ortholog? A. There is no difference. B. Paralogs are within the same species, while orthologs are between different species C. Paralogs are located on the same chromosome, while orthologs are on different chromosomes. D. Paralogs reside within exons, while orthologs reside in introns - ANSWER B Approximately, how many genes does the human genome contain? A. 200 B. 2, C. 20, D. 200,000 - ANSWER C Which is not true of RNA polymerase? a. It cannot begin the 5' end of a new strand without a primer b. It can only travel in the 5' to 3' direction c. It can reconstruct the 3' end of each newly made DNA strand d. It can replace the RNA primer with DNA at the 5 end - ANSWER D

What is the role of condensins in DNA compaction? a. Bind to and neutralize negatively charged DNA b. Alter the nucleosome patterns to condense more tightly c. Cut out unnecessary regions of the DNA d. Condense chromosomes into a tight bundle for mitosis - ANSWER D One of the functions of a centromere is to contribute to proper chromosome segregation. The other is to a. Ensure that proper chromosome arm length is maintained b. Hold sister chromatids together c. develop meiotic chromosome replication d. All of the above - ANSWER B Which of the following will a Barr body be seen? a. XX b. XXY c. XO d. A and B only e. All of the above - ANSWER D Chromatin a. Supports flexibility of form and function for DNA b. Is any complex of DNA and protein found in a cells nucleus c. Behaves as a unit during cell division d. Serves as the starting point of cellular division of eukaryotes - ANSWER B There are _____ usually found in the genetic code. a. 3 start codons and 1 stop codon b. 2 start codons and 2 stop codons c. 1 start codon and 3 stop codons

d. 0 start codons and 4 stop codons - ANSWER C Transcription occurs in the _______ and translation occurs in the _______ of eukaryotic cells. a. Nucleus, nucleus b. cytoplasm, nucleus c. cytoplasm, cytoplasm d. nucleus, cytoplasm - ANSWER D In gel electrophoresis of DNA, fragments move at different rates because they have different a. Sizes b. base sequences c. electrical strengths d. charge densities - ANSWER A The two chromatids of each replicated chromosome must separate from one another and segregate during a. Mitosis b. Meiosis I c. Meiosis I and II d. Mitosis and meiosis I e. Mitosis and meiosis II - ANSWER E The first level of compaction of DNA consists of A. DNA winding around histones to form small nucleosomes. B. tight coiling of DNA with nucleosomes into higher order structures. C. high level compaction into metaphase-type chromosomes. D. histone, DNA, and nonhistone covalent bonding. - ANSWER A The chromosome can be considered a dynamic organelle for _______________ of DNA.

A. expression B. segregation C. replication D. packaging E. All of the choices are correct. - ANSWER E The components of a chromosome include one long DNA molecule and A. phospholipids. B. proteins. C. carbohydrates. D. steroids. E. RNA. - ANSWER B By weight, chromatin consists roughly of A. 1/3 DNA, 1/3 histones, and 1/3 nonhistones. B. 1/3 DNA and 2/3 acidic proteins. C. 1/3 DNA, 1/3 histones, and 1/3 basic proteins. D. DNA, RNA, histones, and 1/4 nonhistones. - ANSWER A Which of the following is not true of prokaryotes? a) Some have the ability to inhabit extreme enviroments b) They lack a nuclear membrane c) They have membrane bound organelles d) All bacteria are prokaryotes e) They are, on average, smaller than eukaryotic cells - ANSWER C If superman were a bacterial cell (prokaryote), what type of genes would not be found on a plasmid within his cell? a) genes that code for flight

b) genes that code for digestion c) genes that code for super strength d) genes that code for x-ray vision e) genes that code for enhanced hearing - ANSWER B When performing gene transfer by transformation, selection for Trp+ transformants is done by a. plate the sample on nutrient media with histidine and no tryptophan b. plate the sample on minimal media with tryptophan, no histidine c. plate the sample on nutrient media with tryptophan, no histidine d. plate the sample on minimal media with neither tryptophan nor histidine e. plate the sample on minimal media with histidine, no tryptophan - ANSWER e Which of the following is not a method of gene transfer within bacteria? a) transfiguration b) transduction c) conjugation d) transformation - ANSWER A Which of the following is the correct sequence of events involved in the lytic cycle? a) phage proteins are expressed, the infected cell bursts, phage particles assemble, phage DNA replicates, phage injects DNA b) the infected cell bursts, phage particles assemble, phage DNA replicates, phage proteins are expressed, phage injects DNA c) phage injects DNA, phage DNA replicates, phage proteins are expressed, phage particles assemble, the infected cell bursts d) phage injects DNA, phage proteins are expressed, phage DNA replicates, phage particles assemble, the infected cell bursts e) phage particles assemble, phage proteins are expressed, phage DNA replicates, phage injects DNA, the infected cell bursts - ANSWER D

All bacteria are... a) eukaryotes b) prokaryotes c) aerobic d) anaerobic - ANSWER B What is not one of the three mechanisms for gene transfer in bacteria? a) transformation b) translation c) Transduction d) Conjugation - ANSWER B Bacterial Chromosomes fold to form nucleoid bodies that exclude what? a) ribosomes b) RNA c) DNA d) Nucleotides - ANSWER A An established condition in which only the desired mutant will grow? a) screen b) enrichment c) selection d) mutagen - ANSWER C Which of the following tools is used to expose DNA within the cell via cell disruption or cell lysis? a) mutation b) DNA extraction c) restriction enzymes d) cloning - ANSWER B

From DNA research, sites of transcription and therefore most of the genes along the length of thechromosome appear to be found in a) heterochromatin a. b) euchromatin b. c) constitutive heterochromatin c. centromeric regions d. gene deserts - ANSWER B A genomic library is a a) collection of DNA fragments from an organism, inserted into vectors. b) collection of restriction enzymes that make regularly spaced cuts in a genome. c) series of DNA fragments generated by chemical cleavage, used to determine sequence. d) set of genes that can be inserted into vectors to confer antibiotic resistance. e) collection of mRNA molecules cloned into vectors - ANSWER A Nonsense codons are a) codons that code for multiple amino acids b) codons that do not code for an amino acid c) Codons that can be read forward or backward d) Start codons - ANSWER B What type of genes arise from duplication and often constitute a gene family? a) Paralogous b) Orthologous c) Genome d) MPSS - ANSWER A Which of the following tools is used to separate DNA fragments, RNA molecules, or polypeptides according to their size through the use of an electric current and an agarose?

a) gel electrophoresis b) Southern blotting c) DNA sequencing d) mutation - ANSWER A Which of the following tools is the protocol for transferring DNA sequences separated by gel electrophoresis onto a filter paper for analysis with a DNA probe? a) mutation b) polymerase chain reaction c) Southern blotting d) restriction enzymes - ANSWER C Which of the following tools is a purified fragment of DNA that is labeled with either a radioactive isotope or a fluorescent dye and is used for identification of complementary sequences via hybridization? a) mutation b) polymerase chain reaction c) Southern blotting d) DNA probe - ANSWER D Which of the following tools is used to determine the order of nucleotides in a segment of DNA or RNA or the order of amino acids in a protein? a) polymerase chain reaction b) sequencing c) DNA probe d) gel electrophoresis - ANSWER B Which of the following tools is used to amplify an identified DNA sequence? a) polymerase chain reaction b) DNA probe

c) sequencing d) mutation - ANSWER A Which of the following tools results in a heritable alteration in a DNA sequence? a) polymerase chain reaction b) DNA probe c) sequencing d) mutation - ANSWER D Which of the following tools is used to expose DNA within the cell via cell disruption or cell lysis? a) mutation b) DNA extraction c) restriction enzymes d) cloning - ANSWER B Which of the following tools recognizes specific sequences of DNA and cuts DNA at the recognized sites? a) mutation b) DNA extraction c) restriction enzymes d) cloning - ANSWER C Which of the following tools is used to create one copy of a DNA fragment at a time, typically through the use of a vector? a) mutation b) DNA extraction c) restriction enzymes d) cloning - ANSWER D Gametes are ...

A) diploid B) contain half the number of chromosomes found in other cells C) generated by meiosis D) B & C E) all of the above - ANSWER D At what part during interphase do chromosomes replicate to form sister chromatids? A) G0 B) G1 C) S D) G2 E) G3 - ANSWER C What occurs during prometaphase of mitosis? A) chromosomes align at the cell's equator B) chromosomes condense and become visible C) Chromosomes decondense and are enclosed in two nuclei D) sister chromatids separate and move to opposite poles E) spindle forms and sister chromatids attach to microtubules from opposite centrosomes - ANSWER E Which of the following is not a substage of prophase I? A) zygotene B) diplotene C) diakinesis D) cytokinesis E) pachytene - ANSWER D Which of the following describes the product rule?