Practice MODERN GENETICS

Transcription

1 Name: Practice MODERN GENETICS 1. Which diagram represents a pair of homologous chromosomes? 8. The diagram below shows some chromosomal alterations. A) B) C) D) Which chromosome represents an alteration known as a deletion? 9. Base your answer to the following question on the list of genetic changes. Choose from the list below that is best described by that statement. 2. Which statement is correct concerning hereditary information? A) A chromosome is composed of many genes. B) A gene is composed of many chromosomes. C) Each chromosome carries the same information. D) Each gene carries the same information. 3. Which sequence correctly represents the arrangement of structures containing genetic material, from the largest to the smallest size? A) chromosome gene nucleus B) nucleus chromosome gene C) gene chromosome nucleus D) gene nucleus chromosome 4. Which statement best describes the process of crossing-over? A) It takes place between homologous chromosomes and results in new gene combinations. B) It takes place between nonhomologous chromosomes and results in an increased gene mutation rate. C) It takes place between homologous chromosomes and results in an increased gene mutation rate. D) It takes place between nonhomologous chromosomes and results in new gene combinations. 5. Although identical twins inherit exact copies of the same genes, the twins may look and act differently from each other because A) a mutation took place in the gametes that produced the twins B) the expression of genes may be modified by environmental factors C) the expression of genes may be different in males and females D) a mutation took place in the zygote that produced the twins 6. A chromosomal alteration in which one or more pairs of homologous chromosomes fail to separate normally during meiotic cell division is known as A) an addition B) crossing-over C) nondisjunction D) translocation 7. Some weed killers, insecticides, and food additives alter the DNA of certain cells. Because of this effect, these substances are known as A) parasites B) mutagens C) contagions D) producers Genetic Changes (1) Translocation (2) Addition (3) Deletion (4) Gene mutation A chromosomal rearrangement is formed after a section breaks off from one chromosome and becomes attached to a nonhomologous chromosome. 10.A single gene mutation results from A) a change in a base sequence in DNA B) recombination of traits C) the failure of chromosomes to separate D) blocked nerve messages 11. As a result of sexual reproduction, an organism can pass a gene mutation to its offspring if the mutation occurs in A) a body cell B) a sex cell C) liver tissue D) white blood cells 12. Phenylketonuria (PKU), a human disease characterized by mental retardation, results from the A) inability to produce a specific enzyme B) increased production of several enzymes C) nondisjunction of chromosomes D) production of poisons by bacteria 13. Which genetic disorder is characterized by a buildup of fatty tissue in the nervous system? A) phenylketonuria B) sickle-cell anemia C) Down syndrome D) Tay-Sachs 14. What is a homozygous condition resulting in the formation of abnormal hemoglobin that distorts certain blood cells known as? A) hemophilia B) phenylketonuria C) Tay-Sachs D) sickle-cell anemia 15. The weakest bonds in a double-stranded molecule of deoxyribonucleic acid exist between the A) deoxyribose sugars B) phosphate groups C) nitrogenous bases D) 5-carbon sugars

2 Base your answers to questions 16 through 18 on your knowledge of biology and on the charts below which show human chromosomes arranged in pairs. 22. Which statement best describes a portion of the molecule represented below? 16. The preparation of these charts for individuals A and B is known as A) microsurgery B) karyotyping C) blood typing D) chemical screening 17. The chromosomes numbered 1 through 22 are known as A) It consists of many ribose sugars. B) It unites with amino acids in the cytoplasm. C) It contains uracil, which functions in protein synthesis. D) It consists of alternating phosphate groups and deoxyribose molecules. 23. The diagram below represents a segment of a gene on two chromosomes. A) ribosomes B) lysosomes C) centrosomes D) autosomes 18. Which genetic disorder in individual A is indicated by the number of chromosomes labeled 21? A) phenylketonuria (PKU) B) Tay-Sacks C) sickle-cell anemia D) Down's syndrome 19. The diagram below illustrates fertilization in a human. The change in the gene sequence is an example of A) an insertion B) a deletion C) a substitution D) a replication 24. Which is the sugar component of a DNA nucleotide? A) adenine B) deoxyribose C) glucose D) phosphate 25. Which molecules are needed to cut and copy segments of DNA? Which type of individual might result from this fertilization? A) a 3n individual B) an individual with Down syndrome C) a normal diploid individual D) a monoploid, colorblind individual 20. In a portion of a gene, the nitrogenous base sequence is T-C-G-A-A-T. Which nitrogenous base sequence would normally be found bonded to this section of the gene? A) A-C-G-T-A-A B) A-C-G-U-U-A C) A-G-C-T-T-A D) U-G-C-A-A-U 21. What do the letters A, G, C, and T represent in nucleotides? A) phosphate groups B) deoxyribose sugars C) nitrogenous bases D) ribose sugars A) reproductive hormones B) carbohydrates C) antibodies D) biological catalysts 26. During the replication of a DNA molecule, separation or "unzipping" of the DNA molecule will normally occur when hydrogen bonds are broken between what two nucleobases? A) thymine and thymine B) guanine and uracil C) adenine and cytosine D) cytosine and guanine 27. A cell begins to produce a new type of protein. This is most likely due to an alteration of the A) structure of the cell membrane B) sequence of bases in a section of a chromosome C) chemical makeup of the cytoplasm D) shape of the antibodies produced by the nucleus

3 28. A mutation occurring in a human can be passed from parent to offspring when it occurs in a A) lung cell, due to exposure to a toxic gas B) gamete formed in the ovary C) body cell undergoing mitosis D) heart cell with chromosome damage 29. What is the complementary messenger-rna sequence for the DNA sequence shown below? 34. The process represented in the diagram occurs on the cell organelle known as a A) vacuole B) ribosome C) chloroplast D) mitochondrion Base your answers to questions 35 through 37 on the diagram below and on your knowledge of biology. The diagram represents a step in protein synthesis. A) C-A-A-G-G-U B) G-T-T-C-C-A C) G-U-U-C-C-A D) C-A-A-G-G-T 30. DNA serves as a template for the synthesis of A) messenger RNA B) cellulose C) starches D) lipids 31. Which statement best describes messenger RNA? A) It transfers polypeptides to the nucleus. B) It is chemically more complex than DNA. C) It has one oxygen atom less than DNA. D) It is composed of a single strand of nucleotides. 32. Some events that take place during the synthesis of a specific protein are listed below. (A) Messenger RNA attaches to a ribosome. (B) DNA serves as a template for RNA production. (C) Transfer RNA bonds to a specific codon. (D) Amino acids are bonded together. (E) RNA moves from the nucleus to the cytoplasm. The correct order of these events is A) B E A C D B) D A E C B C) B C E D A D) C B A E D Base your answers to questions 33 and 34 on the diagram below of a biochemical process that occurs within cells and on your knowledge of biology. 35. If a sequence of nitrogenous bases on DNA strand I is T-A-G-C-C-T-A, the corresponding sequence on the RNA will be A) A-T-C-G-G-A-T B) A-U-C-G-G-A-U C) T-A-G-C-C-T-A D) U-T-C-G-G-U-T 36. During this step in the process of protein synthesis, information is passed from A) DNA strand I to RNA B) DNA strand II to RNA C) RNA to DNA strand I D) RNA to DNA strand II 37. The molecule labeled "RNA polymerase" is classified as A) a carbohydrate B) a lipid C) an enzyme D) a neurotransmitter 38. The genetic code for one amino acid molecule consists of A) five sugar molecules B) two phosphates C) three nucleotides D) four hydrogen bonds 39. Amniocentesis is a process that is used to 33. The process represented in the diagram is A) lipid digestion B) cell respiration C) protein synthesis D) protein hydrolysis A) determine the rate of mutation in embryos B) examine the phenotypes of fruit flies C) detect many genetic disorders in humans before birth D) search for polyploid fruit seeds 40. A single strand containing phosphate, ribose, and the bases adenine, guanine, uracil and cytosine is called A) DNA B) RNA C) enzyme D) sugar E) base

4 41. A eukaryotic cell lacking helicase during DNA replication would A) be incapable of proofreading the newly synthesized strand B) be unable to terminate elongation C) be incapable of unwinding the DNA helix D) catalyze the DNA strand at incorrect locations E) not seal the Okazaki fragments on the lagging strand 42. During DNA replication, the leading strand is easily distinguishable from the lagging strand because A) the leading strand is synthesized 3' to 5' B) the lagging strand is synthesized in separate pieces called Okazaki fragments C) helicases only attach to the leading strand D) the lagging strand is synthesized 5' to 3' E) DNA ligase is attached to the leading strand 43. Although eukaryotic cells contain over a thousand times more DNA than is found in a prokaryotic cell, it only takes a eukaryotic cell a few hours to copy all of its genetic material because A) eukaryotic DNA polymerases delete unnecessary material as it is replicating B) eukaryotic cells follow the semiconservative model for DNA replication C) prokaryotic cells have more than four nucleotide bases D) eukaryotic cells have more than one replication site along its chain of DNA E) eukaryotic cells have shorter segments of DNA 44. Mutations caused by damage to DNA are detected by 50. A couple is considering having a child and would like to be tested beforehand for any chromosomal defects. The best method for this is A) amniocentesis B) bacterial transformation C) gene therapy D) electrophoresis E) karyotyping Base your answers to questions 51 and 52 on the genetic disorder, chosen from the list below, that is best described by that phrase. Genetic Disorders (1) Tay-Sachs (2) Phenylketonuria (3) Sickle-cell anemia (4) Hemophilia 51. Symptoms resulting from the lack of an enzyme needed for the normal metabolism of an amino acid 52. A disorder characterized by crescent-shaped red blood cells with abnormal hemoglobin 53. Watson and Crick described the DNA molecule as a A) straight chain B) single strand C) double helix D) branching chain 54. The diagram below represents Watson and Crick's model of DNA. A) DNA helicase B) DNA ligase C) DNA polymerase I D) DNA primase E) topoisomerase 45. Before a genetic message can leave the nucleus of a eukaryotic cell, it must undergo A) separation B) promotion C) termination D) translation E) transcription 46. If a segment of DNA contains the sequence 5'-GAT TTA ATG-3', the resulting RNA must be A) 3'-CAU UAA AUC-5' B) 3'-CUA AAU UAC-5' C) 3'-CTA TTA TAC-5' D) 3'-CAT TAA ATC-5' E) 3'-GAT TTA ATU-3' 47. The anticodon region can be found A) within a trna molecule B) on the polypeptide chain C) within an mrna molecule D) on the large subunit of the ribosome E) attached to the end of an amino acid The substance indicated by the arrow could be A) thymine. B) deoxyribose. C) ribose. D) uracil. 55. Which of the following scientists determined that DNA is the hereditary material in viruses? A) Hershey and Chase (1952) B) Griffith (1928) C) Watson and Crick (1953) D) Morgan (1950's) E) Meselson and Stahl (1950's) 48. Which of the following best represents the expression of genes? A) DNA RNA Protein B) DNA Protein RNA C) RNA Protein DNA D) RNA DNA Protein E) Protein RNA DNA 49. The end products of translation are A) DNA B) RNA C) lipids D) amino acids E) polypeptides

5 Answer Key review Modern Genetics 1. B 2. A 3. B 4. A 5. B 6. C 7. B 8. D 9. A 10. A 11. B 12. A 13. D 43. D 44. C 45. E 46. B 47. A 48. A 49. E 50. E 51. B 52. C 53. C 54. A 55. A 14. D 15. C 16. B 17. D 18. D 19. B 20. C 21. C 22. D 23. C 24. B 25. D 26. D 27. B 28. B 29. C 30. A 31. D 32. A 33. C 34. B 35. B 36. A 37. C 38. C 39. C 40. B 41. C 42. B