Final Exam Review (Part Two) June 2015 Biology Ms. Flesher

19. Who was the “Father of Genetics”? Gregor Mendel

20. How did Mendel obtain his Parent “P” generation? He allowed the plants to self-pollinate.

21. What is the probability that a homozygous dominant individual and a homozygous recessive individual will have the dominant phenotype? 100% = 1.0 TT t t TtTt TtTt Homozygous Dominant Homozygous Recessive

22. What are true-breeding plants? True-breeding plants always produce offspring each of which have only one form of a trait. Example: If the parents are true-breeding purple flower plants, they will only produce offspring will purple flowers.

23. What did Mendel call his original pure strain of pea plants? P

24. The passing of traits from parent to offspring is called… Heredity

25. A genetic trait that appears in every generation is called… Dominant

26. Mendel’s Law of _____ states that the inheritance of one trait had no effect on the inheritance of the other. Independent Assortment Mendel discovered that the inheritance of one trait had no effect on the inheritance of the other. For example, flower color does not affect the inheritance of plant height.

27. Mendel’s Law of _________ describes how traits can disappear and reappear in a certain pattern from generation to generation. Law of Segregation Law of Segregation

28. Mendel’s Law of ____ states that alleles of a gene separate from each other during meiosis. Segregation

29. Describe the difference between genotype and phenotype. Genotype = Genes (letters) –Example: Bb Phenotype = All traits that are actually expressed, physical appearance –Example: Brown Eyes

30. Describe the difference between homoygous and heteroygous. Homozygous = Two of the same alleles –Example: TT or tt Heterozygous = Two different alleles –Example: Tt

31. Each organism has a unique combination of characteristics encoded in molecules of… DNA DNA

32. What is the primary function of DNA? To store and transmit genetic information

33. Describe the structure of DNA. Every DNA nucleotide contains a sugar, a phosphate group, and a base. DNA consists of two strands of nucleotides joined by hydrogen bonds. The long strands of nucleotides are twisted into a double helix.

34. Molecules of DNA are composed of long chains of… Nucleotides

35. Draw and label the three parts of a nucleotide.

36. The part of DNA for which it is named is the… Sugar (Deoxyribose)

37. Name the two scientists credited with discovering the structure of DNA. Watson & Crick

38. What did Watson and Crick call the double stranded structure of DNA? The Double Helix

39. Describe Chargaff’s Rule. The amount of adenine equals the amount of thymine. The amount of guanine equals the amount of cytosine.

40. What are the base-pairing rules? Adenine—thymine; guanine—cytosine

41. During DNA replication, what does DNA Polymerase do? Catalyzes (speeds up) the addition of nucleotides to form a complementary strand of DNA.

42. During DNA replication, the original strand of DNA has the sequence CCTAGCT. What would the complementary strand of DNA be? GGATCGA

43. List the three types of RNA and their functions. Messenger RNA (mRNA) – carries the message for making proteins Ribosomal RNA (rRNA) – makes up part of ribosomes Transfer RNA (tRNA) – transfers amino acids to ribosomes

44. How is RNA different from DNA? RNA is sometimes single-stranded RNA contains a different sugar molecule RNA contains the nitrogenous base uracil

45. In RNA, adenine base pairs with… Uracil

46. Using the chart of codons on pg. 207, what would the sequence of amino acids be encoded by the following mRNA molecule: CUCAAGUGCUUC? Leu—Lys—Cys—Phe

47. What would the DNA strand be made from the following mRNA strand CUCAAGUGCUUC? GAGTTCACGAAG

48. What are the anticodons for the codons CUCAAGUGCUUC? GAG—UUC—ACG—AAG

49. During translation, a ribosome binds to… mRNA

50. In order for protein synthesis to occur, mRNA must migrate to the… Ribosome

51. What is transcription? The process by which genetic information encoded in DNA is transferred to an RNA molecule.

52. Define codon. Each nucleotide triplet in mRNA that specifies a particular amino acid.

53. What three things can an error in DNA replication cause? MutationsCancer Genetic Variation

54. The X and Y chromosomes are called the… Sex Chromosomes

55. If females are XX then males are… Females = XX Males = XY

56. Which type of mutation happens when a piece of DNA breaks away from its chromosome and attaches to a nonhomologous chromosome? Translocation

57. What is a mutation? A change in a gene due to damage or incorrect copying.

58. Can the effects of a mutation be helpful, harmful or neutral (no effect)? All three! Helpful = Genetic Variation Harmful = Cause Cancer Neutral = have no effect on the person

59. Define Genetic Counseling. Helps identify parents at risk of having children with genetic defects. Assists parents in deciding whether or not to have children. Is costly, but beneficial.

60. What is an X-Linked (Sex- Linked) trait? A trait located on the X chromosome.

61. Who is more commonly affected by X-Linked traits, males or females? Why? Males They only need one recessive trait on their one X chromosome to have that disease/disorder Example: Color-blindness

62. Since the allele for colorblindness is located on the X chromosome, it is said to be a Sex-Linked Trait

63. Consider a cross between a homozygous white-eyed female fruit fly (Drosophila) and a red-eyed male fruit fly. What proportion (percent) of the female offspring would be expected to be white-eyed? What proportion of the male offspring would be expected to be white-eyed. Create an X-Linked Punnett Square to show your work. XrXrXrXr XrXrXrXr XRXRXRXR Y XRXrXRXrXRXrXRXr Red-Eyed Female XRXrXRXrXRXrXRXr XrYXrYXrYXrY White- Eyed Male XrYXrYXrYXrY 0% of females would have white eyes 100% of males would have white eyes Homozygous White-Eyed Female Red-Eyed Male