Metaphase of Mitosis - Genes and Evolution - Past Exam, Exams of Biology

Download Metaphase of Mitosis - Genes and Evolution - Past Exam and more Exams Biology in PDF only on Docsity! Turn over 1 PRIFYSGOL ABERYSTWYTH UNIVERSITY INSTITUTE OF BIOLOGICAL, ENVIRONMENTAL & RURAL SCIENCES SEMESTER 1 EXAMINATIONS 2009 MODULE BS12510 – GENES AND EVOLUTION Time allowed - 2 hours INSTRUCTIONS FOR MULTIPLE CHOICE QUESTIONS Answer all multiple choice questions on one optically marked sheet. You must answer each question in the order in which it appears on the question paper. Complete the boxes on the optically marked sheet to give the following details - name, date, subject, module identifier and student number. Student number should be completed by writing the digits in pencil in the top line of the box and then filling in the bar code boxes below with the first digit represented in column 1, the second digit in column 2 and so on. This is done by striking through the little box with a soft pencil as shown in the instructions on the sheet for marking the correct answers. Other instructions are on the sheet, but note the following- There are five possible answers to each question, only one of them is correct. Record your answers on the optically read sheet by using a soft pencil (HB or softer) to mark the appropriate box thus Do not tick, cross or ring boxes and do not write elsewhere on the form. 5 marks are given for every correct answer. 1 mark is deducted for every incorrect answer. No marks added/deducted for blank answers. If you make a mistake on the optically marked sheet, it can be corrected with a soft eraser. Spare sheets are available in the examination hall. Turn over 2 1. During metaphase of mitosis a) homologous chromosomes form bivalents b) chiasmata are visible c) sister chromatids separate d) chromosomes condense e) chromosomes line up on the equatorial plate. 2. The diagram below shows the relative amount of DNA in the nucleus of a cell as it goes through its mitotic cycle of growth and division. The region marked A represents a) Interphase b) Prophase c) Metaphase d) Anaphase e) Telophase. 3. In horses, black coat colour (E) is dominant over chestnut (e). A black mare had several foals by a chestnut stallion. Some had a chestnut coat and others had a black coat. Identify which one of the following statements is correct. a) The mare was homozygous (EE) and the stallion was homozygous (ee). b) Both the mare and the stallion were heterozygous (Ee). c) The mare was heterozygous (Ee) and the stallion was homozygous (EE). d) The mare was homozygous (ee) and the stallion was heterozygous (Ee). e) The mare was heterozygous (Ee) and the stallion was homozygous (ee). A B C DE A 2 1 Time Turn over 5 13. Identify the incorrect statement below. a) Genes that lie on the same chromosome form a linkage group. b) Genes can exist in several different allelic forms. c) Different genes mutate at different rates. d) Genes are expressed during mitotic metaphase. e) Exchange between homologous DNA strands in meiosis produces new combinations of characters during gamete formation. 14. In a cross between two Drosophila melanogaster strains, one with vestigial wings and red eyes (vg +) and the other with long wings and cinnabar eyes (+ cn) the F1 generation all had long wings and red eyes. In the F2 generation the following numbers and types of progeny were obtained + + 15 wild type + cn 123 cinnabar eyes vg + 141 vestigial wings vg cn 21 vestigial wings and cinnabar eyes The percentage recombination between vg and cn is a) 5 % b) 7 % c) 12 % d) 41 % e) 47 % 15. In a cross between two Drosophila melanogaster strains, one with claret eyes and normal body (cl +) and the other with red eyes and an ebony body (+ eb) the F1 generation all had long wings and red eyes (wild type). In the F2 generation the following numbers and types of progeny were obtained + + 73 + eb 174 cl + 180 cl eb 78 Which of the following statements is correct? a) The two loci show sex linked inheritance. b) There was 30% recombination between cl and eb. c) The two loci show independent segregation. d) There were 354 recombinant flies. e) None of the above. Turn over 6 16. Which one of the following statements is correct? In the human genome a) tandem repeats are abundant in the mitochondrial component b) tandem repeats comprise about 80 % of the genetic material c) less than 2 % of the genetic material represents coding sequences d) introns are translated to form proteins e) there are about 100,000 genes. 17. Which of the following statements is correct? a) Most genes in eukaryotes and prokaryotes contain introns. b) Coupled transcription and translation occurs in eukaryotes. c) Plasmids are commonly found in both eukaryotes and prokaryotes. d) Histones are involved in chromatin condensation in both prokaryotes and eukaryotes. e) The genomes of prokaryotes and of eukaryote organelles share many common features. 18. Which one of the following does not contribute to DNA condensation during nuclear division? a) Nucleosomes. b) Looped domains of chromatin. c) Rosettes of chromatin. d) Histone proteins. e) Centromere. 19. Fred Griffith undertook experiments in which he injected pneumococci directly into the pericardial cavity of mice and monitored their survival. His experiments led to the discovery of a) introns in eukaryotic DNA b) transformation c) transduction d) conjugation e) restriction endonucleases. 20. In five independent conjugation experiments with a prokaryotic organism, the following order of gene transfer was observed. Experiment 1: z-f-j-n-v-o-u-k Experiment 2: t-r-p-y-k-u-o Experiment 3: x-m-d-b-g Experiment 4: m-x-q-a-e Experiment 5: w-s-h-c-z-f-j The organism appears to have a) one linear chromosome b) one circular chromosome c) one linear and one circular chromosome d) two linear chromosomes e) two circular chromosomes. Turn over 7 21. Which one of the following statements is incorrect? a) Histone proteins protect mRNA from degradation during transcription. b) Viruses may contain either DNA or RNA as their genetic material. c) Mitochondria have circular genomes. d) Double-stranded DNA obeys Chargaff’s rule. e) When DNA is fully condensed in metaphase chromosomes, its length is effectively reduced 10,000-fold. 22. In the 19 th Century, Cors Caron (Tregaron Bog) held a thriving population of over 20,000 Welsh boggles. The straightening of the river Teifi during the early part of the twentieth century eliminated key boggle habitat, causing a severe decline in the number of boggles. Recent restoration work by local conservation organisations has succeeded in restoring this habitat and the Cors Caron boggle population has now rebounded to its former levels. However, molecular studies have indicated a worrying lack of genetic diversity compared to similar sized populations of the closely related Northumbrian boggart. This is an example of a) The founder effect b) Directional selection c) Sexual selection d) Balancing selection e) A genetic bottleneck. 23. Which of the following is not an assumption of the Hardy-Weinburg equilibrium? a) No net migration into or out of the population b) No net mutation from one allele to another c) Population size is small d) Mating is random e) All alleles contribute equally to fitness (no selection). 24. Which of the following genetic elements could increase its transmission to the next generation by increasing the proportion of male offspring? a) The Y chromosome. b) The X chromosome. c) The mitochondrial genome. d) The chloroplast genome. e) Chromosome 21. 25. In cats, the ginger allele is recessive and located on the X chromosome. Cats that are heterozygous for the ginger allele have patches of ginger fur (they are tortoiseshell). If I cross a ginger male cat with a black female, which coat colours are possible in the male offspring? a) Black only. b) Ginger only. c) Tortoiseshell only. d) Ginger and tortoiseshell. e) Black and tortoiseshell. Turn over 10 34. Which of the following is not a kind of mutation? a) Transition. b) Translation. c) Missense. d) Samesense. e) Nonsense. 35. Bromouracil is a mutagenic agent because it a) disrupts microtubule formation leading to incorrect chromosome segregation during mitosis b) exists in two tautomeric forms that have different base pairing characteristics c) substantially reduces the fidelity of DNA replication d) inhibits the translation of mRNA on ribosomes e) forms pairs with any of the four bases found in DNA. 36. The fluctuation test of Luria and Delbrück showed that a) the results of experiments can vary from one day to the next b) bacteriophage-resistant mutants arise spontaneously in bacterial populations c) phages eat bacteria d) bacteria eat phages e) none of the above. 37. In DNA the complementary strands a) cannot re-anneal after denaturation following heating to 95 o C b) form a helix in which A pairs with C and T pairs with G c) are held together by covalent bonding between bases on opposite strands d) form a double helix in which one of the grooves is wider than the other e) can be reversibly denatured by heating to 90 o C and then rapid cooling. 38. Phenylketoneuria, alkaptoneuria and albinism are examples of a) enzymes b) metabolic pathways c) inborn errors of metabolism d) sex-linked inheritance e) dominant traits. 39. Messenger RNA a) contains uracil but not adenine b) always remains in the nucleus c) synthesis produces a direct copy of the template strand d) synthesis produces a complementary copy of the template strand e) synthesis occurs in a 5’ to 3’ direction. Turn over 11 40. In prokaryotic ribosomes a) there is no rRNA b) the small subunit contains 5S rRNA c) the small subunit contains 16S rRNA d) the small subunit contains 18S rRNA e) the small subunit contains 5.8S rRNA. 41. The sequence TATAAT in a promoter is a) only found prokaryotes b) always approximately 35 base pairs from the start of transcription c) all that is required for binding of RNA polymerase d) important for DNA unwinding to allow access of RNA polymerase e) only found in eukaryotes. 42. In eukaryotes a) the same RNA polymerase can transcribe rRNA, mRNA and tRNA b) mRNA is transcribed by RNA polymerase I c) mRNA is transcribed by RNA polymerase II d) mRNA is found only in the nucleus e) mRNA is transcribed and translated almost simultaneously. 43. In eukaryotes a) transcription usually starts with a pyrimidine b) the capping reaction is non-enzymic c) mRNA is capped at the 3’ end d) capping involves addition of a C residue to the 5’ end of mRNA e) none of the above. 44. Which of the following will form a perfect duplex with 5’-CATATGCGATCG-3’? a) 5’-CTATAGCGTACG-3’. b) 5’-GTATACGCTAGC-3’. c) 5’-CGTACGCATATG-3’. d) 5’-CGATCGCATATG-3’. e) 5’-GCTAGCGTATAC-3’. 45. In the genetic code a) each amino acid is encoded by a single codon b) codons sometimes overlap with each other c) the codons corresponding to some amino acids differ in prokaryotes and eukaryotes d) every codon encodes an amino acid e) many amino acids are encoded by several codons. 12 46. In the lac operon a) the permease protein allows lactose to leak from bacterial cell b) repressor protein prevents RNA polymerase from transcribing the lacZYA genes c) the repressor protein binds to the galactosidase protein blocking its activity d) the repressor protein binds to the permease protein blocking its activity e) galactosidase controls operon activity. 47. Which of the following is not a constituent of the polymerase chain reaction? a) Mg 2+ ions. b) Nucleoside triphosphates. c) primers. d) DNA polymerase III. e) Target DNA. 48. The restriction enzyme produced by a bacterium does not cut its own DNA because the a) enzyme is found in a different cellular organelle from the DNA b) DNA is protected from the enzyme by methylation of certain bases c) enzyme is not active until released from the bacterium. d) recognition sequence does not occur in the DNA of the bacterium e) DNA is protected from the enzyme by bound histones. 49. If the DNA of an organism has 17 % G, what is the % C? a) 17 %. b) 33 %. c) 34 %. d) 66 %. e) None of the above. 50. Southern hybridization a) is the process by which of Nothofagus (southern beech) trees are pollinated in S. America b) may be employed for detecting specific proteins c) may be employed for detecting specific RNA sequences d) may be employed for detecting DNA sequences e) was developed by Ed Southern for sequencing proteins. END