1. Genetics: The Science of Heredity Chapter 3

2. VA Standards of Learning addressed: LS.1The student will plan and conduct investigations in which a) data are organized into tables showing repeated trials and means; d) sources of experimental error are identified; e) dependent variables, independent variables, and constants are identified; g) continuous line graphs are constructed, interpreted, and used to make predictions; and i) an understanding of the nature of science is developed and reinforced. LS.2The student will investigate and understand that all living things are composed of cells. Key concepts include d) cell division (mitosis and meiosis). LS.3The student will investigate and understand that living things show patterns of cellular organization. Key concepts include b) life functions and processes of cells, tissues, organs, and systems (respiration, removal of wastes, growth, reproduction, digestion, and cellular transport). LS.13The student will investigate and understand that organisms reproduce and transmit genetic information to new generations. Key concepts include a) the role of DNA; b) the function of genes and chromosomes; c) genotypes and phenotypes; d) factors affecting the expression of traits; e) characteristics that can and cannot be inherited; g) historical contributions and significance of discoveries related to genetics. LS.14The student will investigate and understand that organisms change over time. Key concepts include a) the relationships of mutation, adaptation, natural selection, and extinction;

3. Chapter 3, Section 1 Mendel’s Work After completing the lesson, students will be able to: 1.Describe Mendel’s genetics experiments; 2.Identify the factors that control the inheritance of traits in organisms; 3.Explain how genetics use symbols to represent allels.

4. Who was Mendel? Gregor Mendel was a young _________ from a monastery in Central Europe in the mid-1800s Studied math and science at the University of Vienna Tended the monastery’s garden and became curious about why some of the plants had different characteristics, or _______________. Mendel experimented with thousands of pea plants to understand the process of ________, the passing of ______________ from parents to offspring. His work formed the foundation of _________, the scientific study of _______________.

5. Who was Mendel? Gregor Mendel was a young priest from a monastery in Central Europe in the mid-1800s Studied math and science at the University of Vienna Tended the monastery’s garden and became curious about why some of the plants had different characteristics, or traits. Mendel experimented with thousands of pea plants to understand the process of heredity, the passing of traits from parents to offspring. His work formed the foundation of genetics, the scientific study of heredity.

6. Why study PEAS???? Many ______________ that exist in only ____________ forms Pea plant stems are either ___________ or _________________ Garden peas produce a large number of __________________ in one generation making it easy to collect large amounts of _____________ to analyze

7. Why study PEAS???? Many traits that exist in only two forms Pea plant stems are either tall or short Garden peas produce a large number of offspring in one generation making it easy to collect large amounts of data to analyze

8. More on Peas In nature, pea plants are usually __________________. This means that pollen from one flower lands on the pistil of the ____________ flower. A ________________ plant is one that always produces offspring with the same form of a trait as the parent. Stamens Pistil

9. More on Peas In nature, pea plants are usually self- pollinating. This means that pollen from one flower lands on the pistil of the same flower. A purebred plant is one that always produces offspring with the same form of a trait as the parent. Stamens Pistil

10. What are they? The __________ produces ______ sex cells, or eggs, while the _____________ produce pollen, which contains the __________ sex cells. Stamens Pistil

11. What are they? The pistil produces female sex cells, or eggs, while the stamens produce pollen, which contains the male sex cells. Stamens Pistil

13. Self-Pollination

14. __________ ____________ _____________ When Mendel crossed __________________tall and short plants, all the offspring in the F 1 Generation were tall. In the F 2 Generation, three fourths of the plants were tall, while one fourth were short.

15. P Generation F 1 Generation F 2 Generation When Mendel crossed purebred tall and short plants, all the offspring in the F 1 Generation were tall. In the F 2 Generation, three fourths of the plants were tall, while one fourth were short.

16. Other Traits Mendel studied seven traits in garden peas: seed shape, _________ __________, seed coat color, ________ ________, pod color, _________ _________, and stem height. The results in each experiment were ___________ to those observed with stem height.

17. Other Traits Mendel studied seven traits in garden peas: seed shape, seed color, seed coat color, pod shape, pod color, flower position, and stem height. The results in each experiment were similar to those observed with stem height.

18. Book Work Turn to page 89 in your text book. Complete the chart on the Genetics of Pea Plants handout. When it is complete - place it in your binder.

19. Dominant and Recessive Alleles Mendel reasoned that _______________ factors must control the _____________ of traits in peas. The ___________ that control in each trait exist in __________. One factor from the female parent and one factor from the male parent. Mendel went on to reason that one factor in a pair can __________, or _________, the other factor. Tallness ____________ the shortness factor.

20. Dominant and Recessive Alleles Mendel reasoned that individual factors must control the inheritance of traits in peas. The factors that control in each trait exist in pairs. One factor from the female parent and one factor from the male parent. Mendel went on to reason that one factor in a pair can mask, or hide, the other factor. Tallness masked the shortness factor.

21. Alleles Cont’d Scientists call the factors that control traits _________. They call the different forms of a gene ____________. Individual _____________ control the inheritance of traits. Some alleles are __________, while other alleles are ___________. ____________ allele is one whose trait always shows up in the organism when the allele is present. A _____________ allele, on the other hand, is masked or covered up, whenever the dominant allele is present.

22. Alleles Cont’d Scientists call the factors that control traits genes. They call the different forms of a gene alleles. Individual alleles control the inheritance of traits. Some alleles are dominant, while other alleles are recessive. Dominant allele is one whose trait always shows up in the organism when the allele is present. A recessive allele, on the other hand, is masked or covered up, whenever the dominant allele is present.

23. Understanding Mendel’s Crosses Understanding Mendel’s Crosses – Definition: Hybrid – An organism that has two different alleles for a trait;

24. Mendel Today known as the ________ ___ _____ However, his work had been forgotten for ____ _________ before being rediscovered in _________ by three different scientists who recognized his the importance of his work.

25. Mendel Today known as the Father of Genetics However, his work had been forgotten for 34 years before being rediscovered in 1900 by three different scientists who recognized his the importance of his work.

26. Chapter 3 Section 2 Probability and Genetics After completing the lesson, students will be able to: 1.Describe the principles of probability and how Mendel applied them to inheritance; 2.State how geneticists use Punnett squares; 3.Explain the meanings of the terms phenotype, genotype, homozygous, heterozygous, and cocominance.

27. Mini Lab Mini Lab Mini Lab What is the Chance In your lab notebook: 1.Suppose you were to toss a coin 20 times. Predicts how many times the coin would land “heads up” and how many times it would land “tails up.” 2.Now test your prediction by tossing a coin 20 times. Record the number of times the coin lands heads up and the number of times it land tails up. 3.How did steps 1 and 2 compare?

28. ________________ ________________ is the ___________ that a particular event will occur. The laws of _________________ predict what is likely to occur, not necessarily what will occur. However, the more tosses you make, the closer your actual results will be to the results predicted by probability.

29. Probability Probability is the likelihood that a particular event will occur. The laws of probability predict what is likely to occur, not necessarily what will occur. However, the more tosses you make, the closer your actual results will be to the results predicted by probability.

30. __________ and Probability ___________ was the first scientist to _______________ that the principles of probability can be used to predict the results of genetic crosses.

31. Mendel and Probability Mendel was the first scientist to recognize that the principles of probability can be used to predict the results of genetic crosses.

32. _____________ Squares A ____________ Square is a chart that shows all the possible combinations of ___________ that can result from a _________ _____. Geneticists use _____________ Squares to show all the possible outcomes of a genetic cross and to determine the probability of a particular outcome.

33. Punnett Squares A Punnett Square is a chart that shows all the possible combinations of alleles that can result from a genetic cross. Geneticists use Punnett Squares to show all the possible outcomes of a genetic cross and to determine the probability of a particular outcome.

34. Punnett Square (25%) Tt (25 %) Tt (25%) Tt (25%) Tt T T tttt

35. Punnett Square (25%) TT (25%) Tt (25%) Tt (25%) tt T t TtTt

36. Now you try….. B B BbBb

37. Now you try….. BB Bb B B BbBb

38. Terms An organism’s _________________ is its physical appearance, or its visible traits. (Ex. tall or short stems) An organism’s _________________ is its genetic makeup. __________ ______ ______________ _________ ________TT Tall________ tt

39. Terms An organism’s phenotype is its physical appearance, or its visible traits. (Ex. tall or short stems) An organism’s genotype is its genetic makeup. Phenotype and Genotype PhenotypeGenotype TallTT TallTt Shorttt

40. More Terms An organism that has two identical alleles for a trait is said to be _______________. An organism that has two different alleles for a trait is said to be _______________. ______________ used the term _______________ to describe ______________. PhenotypeGenotype ___________ Or ___________ TallTT ___________ TallTt ___________ Shorttt ___________

41. More Terms An organism that has two identical alleles for a trait is said to be homozygous. An organism that has two different alleles for a trait is said to be heterozygous. Mendel used the term hybrid to describe heterozygous. PhenotypeGenotype Homozygous Or Heterozygous TallTT Homozygous TallTt Heterozygous Shorttt Homozygous

42. One More Term In ___________________, the alleles are neither dominant nor recessive. As a result, both alleles are expressed in the offspring.

43. One More Term In codominance, the alleles are neither dominant nor recessive. As a result, both alleles are expressed in the offspring.

44. If Erminette chickens reproduced….

45. What is this an example of? _____________________

46. What is this an example of? CODOMINANCE – Roan Cattle are an example of codominance

47. Chapter 3, Section 3 The Cell and Inheritance After completing the lesson, students will be able to: Describe chromosomes and their role in inheritance; Identify and describe the events that occur during meiosis.

48. Walter Sutton In 1903, Walter Sutton, an ________ geneticist, added an important piece of information to the understanding of genetics. Sutton was studying the cells of __________________. He was trying to understand how sex cells form. ___________ – the male sex cell ___________ – the female sex cell

49. Walter Sutton In 1903, Walter Sutton, an American geneticist, added an important piece of information to the understanding of genetics. Sutton was studying the cells of grasshoppers. He was trying to understand how sex cells form. Sperm – the male sex cell Egg – the female sex cell

50. Sperm and Egg

51. More on Sutton Sutton became particularly interested in the movement of _____________ during the ________________ of sex cells. Sutton hypothesized that ______________ were the _______ to understanding how offspring come to have _______________ similar to those of their parents.

52. More on Sutton Sutton became particularly interested in the movement of chromosomes during the formation of sex cells. Sutton hypothesized that chromosomes were the key to understanding how offspring come to have traits similar to those of their parents.

53. Chromosomes and Inheritance Sutton knew that structures inside cells must be responsible for the inheritance of ______________. He needed evidence to support his __________________________ that _________________________ were those structures. What he discovered:

54. Chromosomes and Inheritance Sutton knew that structures inside cells must be responsible for the inheritance of genes. He needed evidence to support his hypothesis that chromosomes were those structures. What he discovered:

55. Sutton Discovered Grasshoppers have ____ chromosomes in each of their body cells. Grasshopper’s sex cells have only _____ chromosomes. The fertilized egg that forms has _______ chromosomes.

56. Sutton Discovered Grasshoppers have 24 chromosomes in each of their body cells. Grasshopper’s sex cells have only 12 chromosomes. The fertilized egg that forms has 24 chromosomes.

57. Sutton’s Conclusion Sutton concluded that the ___________ carried Mendel’s heredity factors, or __________ from one generation to the next. In other words, _____________ _______________________________. Sutton’s idea became known as the __________ _________ ___ ________ that states: genes are carried from parents to their offspring on chromosomes.

58. Sutton’s Conclusion Sutton concluded that the chromosomes carried Mendel’s heredity factors, or genes from one generation to the next. In other words, genes are located on chromosomes. Sutton’s idea became known as the chromosome theory of inheritance that states: genes are carried from parents to their offspring on chromosomes.

60. Meiosis Meiosis is the process by which the number of chromosomes is _______ by half to form sex cells – ______ _____ ______. During meiosis, the chromosome pairs _____________ and are __________________ to two different cells. The resulting sex cells have only half as many chromosomes as the other cells in the organism.

61. Meiosis Meiosis is the process by which the number of chromosomes is reduced by half to form sex cells – sperm and eggs. During meiosis, the chromosome pairs separate and are distributed to two different cells. The resulting sex cells have only half as many chromosomes as the other cells in the organism.

62. Mini Lab Mini Lab Mini Lab Turn to page 105 in your text book. Draw the stages of Meiosis. Label and write a description (your own or what is in the book) of the four stages.

63. Meiosis and Punnett Squares The Punnett square shows how ________ separate when sex cells form during meiosis. It also shows the possible __________ combinations that can result after fertilization occurs. Tt Parent Cells Possible Sperm Cells Tt Possible egg cells

64. Meiosis and Punnett Squares The Punnett square shows how alleles separate when sex cells form during meiosis. It also shows the possible allele combinations that can result after fertilization occurs. Tt Parent Cells Possible Sperm Cells Tt Possible egg cells TTTt tt

65. Chromosomes ____________ of the organism doesn’t determine the number of chromosomes: _____________ have 46 chromosomes _____________ have 78 chromosomes _____________ have 56 chromosomes Chromosomes are made up of many ____________ joined together like beads on a string. Your body has _____ pairs of chromosomes that contain more than _____________ genes. Each gene controls a _________ ____________.

66. Chromosomes Size of the organism doesn’t determine the number of chromosomes: Humans have 46 chromosomes Dogs have 78 chromosomes Silkworms have 56 chromosomes Chromosomes are made up of many genes joined together like beads on a string. Your body has 23 pairs of chromosomes that contain more than 60,000 genes. Each gene controls a particular trait.

67. Chromosomes -Genes are located on _________________. They may have different __________ for some genes and the same for others.

68. Chromosomes -Genes are located on chromosomes. They may have different alleles for some genes and the same for others.

69. Chapter 3, Section 4 The DNA Connection After completing the lesson, students will be able to: Explain the term “genetic code”; Describe the process by which a cell produces proteins; Describe different types of mutations and how they affect organisms.

70. The Genetic Code The main function of genes is to control the __________ of ______________ in the organism’s cells. __________________ help to determine the __________, _____________, and many other traits of an organism.

71. The Genetic Code The main function of genes is to control the production of proteins in the organism’s cells. Proteins help to determine the size, shape, and many other traits of an organism.

72. Keeping it in perspective! ___________ _______________ ____ _______ _______

73. Keeping it in perspective! Cell Chromosome DNA Molecule Nitrogen Bases

74. Review of Chapter 2 DNA is a major component of chromosomes. DNA is made up of four different Nitrogen Bases – adenine (A), thymine (T), guanine (G), and cytosine (C) – these bases form the rungs on the DNA ladder. A single gene on a chromosome may contain anywhere from several hundred to a million or more of these bases that are arranged in a specific order.

75. Cracking the Code The order of the _____________ ____________ along a gene forms a _______ ___________ that specifies what type of ___________ will be produced.

76. Cracking the Code The order of the nitrogen bases along a gene forms a genetic code that specifies what type of protein will be produced.

77. Cracking the Code In a genetic code, a group of three bases codes for the attachment of a specific _________ _______. _______ __________ are the building blocks of __________. The order of the bases determines the order in which ________ ________ are put together to form a __________.

78. Cracking the Code In a genetic code, a group of three bases codes for the attachment of a specific amino acid. Amino acids are the building blocks of proteins. The order of the bases determines the order in which amino acids are put together to form a protein.

79. How Cells Make Proteins _______ ___________ is the production of proteins During _________ __________, the cell uses information from a gene on a chromosome to produce a specific protein. _________ _____________ takes place on the ______________ in the cytoplasm outside the nucleus __________________ are inside the nucleus HOW does the information needed to produce proteins get out of the nucleus and into the cytoplasm???

80. How Cells Make Proteins Protein synthesis is the production of proteins During protein synthesis, the cell uses information from a gene on a chromosome to produce a specific protein. Protein synthesis takes place on the ribosomes in the cytoplasm outside the nucleus Chromosomes are inside the nucleus HOW does the information needed to produce proteins get out of the nucleus and into the cytoplasm???

82. The Role of RNA The _______ ___________ is called ribonucleic acid or RNA – RNA carries the genetic code from the DNA inside the nucleus into the cytoplasm. RNA and DNA are similar, but DNA looks like one side of the ladder. RNA contains a different ______________ molecule then DNA. Instead of thymine, RNA contains __________. _______________ ________ copies the coded message from DNA in the nucleus and carries the message into the cytoplasm. Another type of RNA, called ______________ __________, carries amino acids and adds them to the growing protein.

83. The Role of RNA The genetic messenger is called ribonucleic acid or RNA – RNA carries the genetic code from the DNA inside the nucleus into the cytoplasm. RNA and DNA are similar, but DNA looks like one side of the ladder. RNA contains a different sugar molecule then DNA. Instead of thymine, RNA contains uracil. Messenger RNA copies the coded message from DNA in the nucleus and carries the message into the cytoplasm. Another type of RNA, called transfer RNA, carries amino acids and adds them to the growing protein.

84. Handout and Book Work Turn to pages 110 and 111 in your textbook. Complete the handout on Protein Synthesis. When the handout is complete read pages 110-112 in your textbook about Mutations.

85. Mutations Some of the changes brought about by mutations are harmful to an organism. Other mutations, however, are helpful, and still others are neither harmful nor helpful.

86. Helpful Mutations Monarch ButterflyViceroy Butterfly Birds do not like the taste of monarch butterflies. Many years ago the viceroy butterflies looked different. Through various mutations in appearance the viceroy looks like the distasteful monarch butterfly.