Semester_Two_Final_Examinations__2014_BIOL1020_Sample

This exam paper must not be removed from the venueVenue____________________ Seat Number________Student Number |__|__|__|__|__|__|__|__| Family Name _____________________ First Name_____________________The final exam has a total of 100 marks and is worth 50% of your final gradePart A - Multiple choice questions (1 mark each):MARK MULTIPLE CHOICE QUESTIONS ON COMPUTER ANSWER SHEET. Indicate the best answer for each question.Note: Some questions have 4 choices, some have 51. DNA and RNA are made from building blocks called nucleotides. A nucleotidefor use in RNA synthesis consists of which of the following generalcomponents?a. glucose, a nitrogenous base and a phosphate groupb. a ribose sugar and a nitrogenous basec. a deoxyribose sugar, a nitrogenous base and a phosphate groupd. a ribose sugar, a nitrogenous base and a phosphate group2. Indicate which complex carbohydrate humans store as their primary energysource and by what type of general catabolic reaction this polysaccharide is metabolized in humansa. chitin, dehydration synthesis reactionb. glycogen, dehydration synthesis reactionc. peptidoglycan, hydrolysisd. glycogen, hydrolysise. starch, hydrolysis3. Oxidative phosphorylation is the final stage of cellular respiration and themain pathway of aerobic energy generation from glucose. Which of thefollowing statements is NOT true?a. ATP and NADH are used as ‘input’ into the electron transport chainb. The electron transport chain produces a proton gradient across the innermitochondrial membranec. FADH2 cannot be used by the electron transport chaind. The electron transport chain is made up of several membrane proteincomplexese. ATP synthesis by chemiosmosis requires about 3 protons per ATP molecule4. Which reaction is most likely to be exergonic?a. anabolic reactionb. ion transportc. molecular transportd. catabolic reactione. endergonic reactions5. What is the end product of both binary fission and mitosis?a. two daughter cells identical to the parent cellb. four daughter cells identical to the parent cellc. one cell carrying additional chromosomes imported from an engulfed celld. one cell with corrected DNAe. four daughter cells, each with half of the parent cell's chromosomes6. If a Cdk-cyclin complex becomes more abundant in G2 phase and disappearsbefore G1, what does that suggest?a. The cyclin component is produced at the beginning of G2 and broken down atthe end of G2b. It is not needed for cell divisionc. The complex is needed to synthesize DNAd. The cyclin component is recycled rather than synthesized anew every cyclee. The complex helps the cell move past the G2 checkpoint7. Many human genes cannot be expressed when inserted into bacterial cells.This is due to...a. Redundancy of the genetic codeb. Ambiguity of the genetic codec. The presence of introns in eukaryotic genesd. The inability of bacterial RNA polymerase to transcribe DNA sequences froma humane. The inability of bacterial DNA polymerase to replicate DNA sequences from ahuman8. Which of the options below indicates the correct decreasing density ofpacking DNA?a. DNA > Chromatin > Nucleosome > Chromosomeb. DNA > Chromatin > Chromosome > Nucleosomec. DNA > Nucleosome > Chromatin > Chromosomed. Chromosome > Chromatin > Nucleosome > DNAe. Chromatin > Chromosome > Nucleosome > DNA9. Which of the following does NOT form a part of the translation process?a. mRNAb. DNAc. Proteind. rRNAe. tRNA10. An mRNA has the sequence of 5’-AUGAAAUCCUAG-3’. What is the templateDNA strand for this sequence?a. 5’-TACTTTAGGATC-3’b. 5’-ATGAAATCCTAG-3’c. 5’3’d. 5’-CUAGGAUUUCAT-3’e. none of the above11. An unfertilized egg contains many mRNAs that should not be translated untilfertilization occurs. Which of these regulatory strategies would be mostappropriate?a. Histone methylationb. Alternative splicingc. mRNA degradationd. Blocking translation initiatione. Histone acetylation12. Which of the following enzymes helps the +sense RNA virus Poliovirus to makemultiple copies of its genome?a. RNA dependent RNA polymeraseb. RNA dependent DNA polymerasec. DNA dependent RNA polymerased. Reverse transcriptasee. DNA Polymerase I13. Which of the following is NOT a feature of plasmids?a. They can exist only as a single copy within a host cellb. They can replicate independently from host DNAc. They remain separate from the bacterial genomed. They carry genes that may confer an advantage to the host celle. They carry an origin of replication14. Which of the following protects bacterial DNA from its own restrictionenzymes?a. Histonesb. Separation of the DNA within the nuclear membranec. Chemical modification of recognition sitesd. Presence of plasmidse. Nothing15. Which of the following involves direct DNA transfer from cell to cell?a. Conjugationb. Transformationc. Transductiond. Transposone. None of the above16. Why do RNA virus genomes need to encode some of their own enzymes forreplication?a. Viruses need the enzymes to enter the cell.b. Host cells lack the polymerase the viruses need to replicate their genomes.c. Host cells degrade their own enzymes when viruses enter the cell.d. Viruses lack the lipids they need to make envelopes.e. Viruses need the enzymes in order to metabolize host cell products.17. Co-ordinated regulation of gene expression in bacteria is achieved by:a. Using the same transcriptional regulators to control expression of genes spreadthroughout the genomeb. The presence of identical origins of replication in both plasmids and genomicDNAc. A single operon controlling the expression of genes required for a given processd. Polyadenylation of mRNAse. Chemical modification of the histones associated with the bacterial DNA18. Chestnut is dominant to white colour in horses. Since chestnut horses command ahigher price in the market, a horse breeding farm breeds a chestnut stallion with 10 white mares and gets 6 white and 4 chestnut foals as progeny. They had expected that all the progeny would be chestnut. What mistake did they make?a. They assumed that the chestnut allele was more common than whiteb. They assumed that the white mares were homozygousc. They assumed that there were more chestnut alleles than whited. They assumed that the chestnut stallion was true breedinge. Both a & d are correct19. The fact that all seven of the pea plant traits studied by Mendel obeyed theprinciple of independent assortment means that:a. All of the genes controlling the traits behaved as if they were on differentchromosomes.b. All of the genes controlling the traits were located on the same chromosome.c. The diploid number of chromosomes in the pea plants was 7.d. None of the traits obeyed the law of segregation.e. The formation of gametes in plants occurs by mitosis only.20. Alleles are best described as:a. Traits that can be scored.b. Multiple genes that control the same trait.c. Phenotypes.d. Alternative forms of genes.e. The first generation following a genetic cross.21. A 0.1% frequency of recombination is observed:a. Only on genetic maps of viral chromosomes.b. On unlinked chromosomes.c. Between genes located very close to one another on the same chromosome.d. Only in sex chromosomes.e. Between any two genes on different chromosomes.22. In humans, height is determined by a number of factors, and it exists along acontinuum and not as discrete quantities. Which term best describes thisphenomenon?a. Polygenic inheritanceb. Pleiotropyc. Overdominance
d. Incomplete dominance
e. Duplicate interaction
23. Recall that fur coloration in Labrador retriever dogs is an epistatic traitcontrolled by the genes for “brown coat color” and “extension”, whereby all ee dogs have the yellow fur phenotype. Which cross cannot yield brownpuppies?a. Black X blackb. Brown X Brownc. Yellow X yellowd. Black X Browne. A and C24. Which of the following is NOT a way in which transposable elements arethought to contribute to evolution?a. They can facilitate recombination between chromosomes.b. They can insert into a protein-coding sequence and change its expression.c. They can cause duplications of entire chromosomes.d. They can carry entire genes with them to a new position in the genome.e. They take individual exons with them during transposition.25. Epigenetic regulation of gene expression is determined by:a. The nucleotide sequence of the gene’s promoterb. DNA methylationc. Packaging of DNA into chromatind. Histone modificatione. All but A26. A mutation occurs during meiosis. What is the least likely outcome for theresultant offspring containing this mutated allele?a. The mutation is neutral: it has no discernable fitness effectb. The mutation is lethal: the offspring does not survivec. The mutation is advantageous: the offspring has higher fitness than the parent.d. The mutation is somewhat deleterious: the offspring has lower fitness than theparent but does not die outright.27. Which of the following statements is true of a hypothetical highly diversepopulation in which no changes in allele frequency have been observed in 100 years?a. It is not capable of evolution.b. It is perfectly adapted to its environment.c. It most likely does not exist outside of hypothetical mathematical models.d. It is most likely a small population.e. None of the answers are correct.28. Which of the following populations would most likely adapt to environmentalchanges?a. A population with high epigenetic diversityb. A population with moderate genetic diversityc. A population with high average heterozygosityd. A population with low genetic diversity
e. A population with low average heterozygosity
29. In order to provide access to a new airport, a road was built through apreviously undisturbed forest, which isolated a small group of deer from the rest of its population. After several years, conservation biologists determined that 75% of the individuals in the isolated population demonstrated a recessive phenotype that is rare in the rest of the population. How would you determine if this is due to inbreeding or genetic drift?a. Compare the number of heterozygotes in the two populations.
b. Compare the number of heterozygotes to homozygotes over time in the isolatedpopulation.c. Determine the fitness of the recessive phenotype.d. Compare the selection coefficients in the two populations.
e. Determine the proportion of breeding individuals in the isolated population.30. Which of the following statements is NOT a characteristic of a bacterialgenome?a. Almost without exception, the genome will consist of multiple chromosomesb. It will be a circular, double-stranded DNA moleculec. The genes will not contain intronsd. Approximately half of the DNA will encode proteinse. It will usually be between 0.5 and 10 million base pairs in lengthEND OF MULTIPLE CHOICE QUESTIONSPart B - Short answer questions(Marks vary. See individual questions for details):MARK YOUR ANSWERS DIRECTLY ON THIS EXAMINATION PAPER.GENES TO PROTEINS1. The Central Dogma of Molecular Biology describes the flow of information in acell. Briefly name and describe the two key processes that the cell performs in order to transmit and utilize genetic information. A full answer should specify the template and the end product of each process, and the location of each process inside a eukaryotic cell.(6 marks)2. In eukaryotes some gene coding regions can produce different yet similarproteins. Name and briefly describe the process that creates these alternative isoforms of a protein. Sketching a simple diagram is recommended. (4 marks)3. The lac operon is both under positive and negative regulation.a. Draw a diagram including the key elements of the lac operon. (3 marks)b. Describe the conditions required for positive stimulation of the lac operon(hint: think about glucose and lactose levels). (3 marks)c. Describe the molecular events that lead to positive regulation of the lacoperon. (2 marks)DNA REPLICATION4. Define and compare a bacteriophage lytic cycle and lysogenic cycle. (3 marks)5. a. Name and briefly describe three ways that DNA is moved between bacterialcells. (3 marks)b. What is the advantage to bacteria of having these DNA movementmechanisms? (2 marks)GENOTYPES and PHENOTYPES6. In the fruit fly Drosophila melanogaster, wild type red eyes are a dominanttrait, whereas white eyes are a recessive trait. You are given a red-eyed fly.How would you determine the genotype of this fly using traditional crossing experiments? Include in your answer the possible results and what they mean.(4 marks)7. You are interested in two phenotypic traits, one has a heritability of 0.8 and theother has a heritability of 0.4. You want to find the approximate location ofgenes controlling these phenotypes using a linkage mapping approach. But, you only have enough grant money to do this for one trait. Which one would you have more chance of success with and why?(Hint: the equation for heritability is, H2 = V G / V P) (3 marks)8. QTLa. What does the acronym QTL stand for? (1 mark)b. Define a QTL in your own words. (2 marks)c. Is a QTL the gene for a phenotypic trait? Briefly explain. (2 marks)INDEPENDENT ASSORTMENT and SEGREGATION9. Using a Punnett square, show the genotypes of gametes and offspring that areexpected from the dihybrid cross, PpSs x Ppss. Assume independentassortment. (3 marks)UNDERLINE all your CAPITAL LETTERS to clarify your answer:Capital P and S should be labelled as P and SLower case p and s should not be underlined10. P is a dominant allele for purple flower colour and p is the recessive whiteallele, whereas S is a dominant allele for smooth seed coat and s is therecessive wrinkled allele. Give the phenotypes that can result in the progeny of the cross described above as well as their expected ratios. (3 marks)PEDIGREES11. Annotate the pedigree shown below with the genotypes of all members of thepedigree using the gene symbol ‘A’for the dominant allele and ‘a’ for therecessive allele. (2 marks)a. Is the allele for the trait in the following pedigree most likely to beautosomal, X-linked or sex-limited? Why? (1 mark)b. Is the allele for the trait in the following pedigree most likely to bedominant or recessive? Why? (1 mark)c. Which symbol is used to indicate a male? Which symbol is used toindicate a female? (1 mark)d. What does shading of the symbols indicate? (1 mark)MICROBIOMES12. In no more than 1-2 sentences each, answer each of the following questionsregarding the human microbiome(s):a. How many times larger is the cell number in the total human microbiomerelative to the number of cells in the human host? (1 mark)b. What is the approximate number of species comprising the total humanmicrobiome? (1 mark)c. How many times larger is the gene number in the total human microbiomerelative to the gene number in the human host? (1 mark)d. What is an example of a beneficial effect of a microbiome? (1 mark)e. What is an example of a harmful effect of a microbiome? (1 mark)HARDY-WEINBERG13. Normal homozygous individuals (SS) have normal blood cells that are easilyinfected with the malarial parasite. Thus, if exposed to malaria many of these individuals become very ill from the parasite and many die. Individualshomozygous for the sickle-cell trait (ss) have red blood cells that readilycollapse when deoxygenated. Although malaria cannot grow in these redblood cells, individuals often die because of the genetic defect. However,individuals with the heterozygous condition (Ss) have some “sickling” of red blood cells, but generally not enough to cause mortality. In addition, malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygousconditions. If 9% of an African population is born with a severe form of sickle-cell anaemia (ss), what percentage of the population will be more resistant to malaria because they are heterozygous (Ss) for the sickle-cell gene? Show your calculations. (5 marks)PRACTICAL QUESTIONS14. Calculate the volume (in mL) of a 0.2 M solution containing 1.17 g of NaCl (MW= 58.5). Show your calculations. (3 marks) 15. You visualise a 350 base pair long DNA product from a PCR experiment byrunning it on an agarose gel. Next to the lane containing your product, there isa lane containing a 200 bp ladder so that you can determine the size of yourPCR product. You run the gel for two hours at 100 volts. How would theresults compare if you used a 1% w/v agarose gel as opposed to a 2% w/vagarose gel? Include results for both the PCR product and the ladder and how the two lanes would compare to each other. (3 marks) 16. What is a “null hypothesis”? How does it apply to scientific experiments?(4 marks)END OF EXAMINATION。