1. End Show Slide 1 of 32 Copyright Pearson Prentice Hall 11-1 The Work of Gregor Mendel

2. End Show 11-1 The Work of Gregor Mendel Slide 2 of 32 Copyright Pearson Prentice Hall Gregor Mendel’s Peas Genetics is the scientific study of heredity. Gregor Mendel was an Austrian monk, who worked with ordinary garden peas to understand heredity. Gregor Mendel’s Peas

3. End Show 11-1 The Work of Gregor Mendel Slide 3 of 32 Copyright Pearson Prentice Hall Gregor Mendel’s Peas Mendel knew that the male part of each flower produces pollen, (containing sperm). the female part of the flower produces egg cells.

4. End Show 11-1 The Work of Gregor Mendel Slide 4 of 32 Copyright Pearson Prentice Hall Gregor Mendel’s Peas Fertilization: sexual reproduction where a sperm joins with an egg to produce a new cell. Pea flowers are self-pollinating.

5. End Show 11-1 The Work of Gregor Mendel Slide 5 of 32 Copyright Pearson Prentice Hall Gregor Mendel’s Peas Mendel had true-breeding pea plants: if allowed to self-pollinate, produce offspring identical to themselves. Cross-pollination Mendel was able to produce seeds that had two different parents.

6. End Show 11-1 The Work of Gregor Mendel Slide 6 of 32 Copyright Pearson Prentice Hall Genes and Dominance A trait: a specific characteristic that varies from one individual to another. Mendel studied seven pea plant traits, each with two contrasting characters. He crossed plants with each of the seven contrasting characters and studied their offspring.

7. End Show 11-1 The Work of Gregor Mendel Slide 7 of 32 Copyright Pearson Prentice Hall Genes and Dominance P (parental) generation: Each original pair of plants. The offspring are called the F 1, or “first filial,” generation. Hybrids: Offspring of crosses between parents with different traits.

8. End Show 11-1 The Work of Gregor Mendel Slide 8 of 32 Copyright Pearson Prentice Hall Genes and Dominance

9. End Show 11-1 The Work of Gregor Mendel Slide 9 of 32 Copyright Pearson Prentice Hall Genes and Dominance Mendel's first conclusion: biological inheritance is determined by factors that are passed from one generation to the next. Genes: the factors that determine traits.

10. End Show 11-1 The Work of Gregor Mendel Slide 10 of 32 Copyright Pearson Prentice Hall Genes and Dominance Each of the traits Mendel studied was controlled by one gene that occurred in two contrasting forms that produced different characters for each trait. Alleles: The different forms of a gene. Mendel’s second conclusion: the principle of dominance.

11. End Show 11-1 The Work of Gregor Mendel Slide 11 of 32 Copyright Pearson Prentice Hall Genes and Dominance The principle of dominance states that some alleles are dominant and others are recessive.

12. End Show 11-1 The Work of Gregor Mendel Slide 12 of 32 Copyright Pearson Prentice Hall Segregation Mendel crossed the F 1 generation with itself to produce the F 2 (second filial) generation. The traits controlled by recessive alleles reappeared in one fourth of the F 2 plants.

13. End Show 11-1 The Work of Gregor Mendel Slide 13 of 32 Copyright Pearson Prentice Hall Mendel's F 2 Generation P Generation F 1 Generation Tall Short F 2 Generation Segregation

14. End Show 11-1 The Work of Gregor Mendel Slide 14 of 32 Copyright Pearson Prentice Hall Segregation The reappearance of the trait controlled by the recessive allele indicated that at some point the allele for shortness had been separated, or segregated, from the allele for tallness.

15. End Show 11-1 The Work of Gregor Mendel Slide 15 of 32 Copyright Pearson Prentice Hall Segregation Mendel suggested that the alleles for tallness and shortness in the F 1 plants segregated from each other during the formation of the sex cells, or gametes.

16. End Show 11-1 The Work of Gregor Mendel Slide 16 of 32 Copyright Pearson Prentice Hall Segregation Alleles separate during gamete formation.

17. End Show - or - Continue to: Click to Launch: Slide 17 of 32 Copyright Pearson Prentice Hall 11-1

18. End Show Slide 18 of 32 Copyright Pearson Prentice Hall 11-1 Gametes are also known as a.genes. b.sex cells. c.alleles. d.hybrids.

19. End Show Slide 19 of 32 Copyright Pearson Prentice Hall 11-1 The offspring of crosses between parents with different traits are called a.alleles. b.hybrids. c.gametes. d.dominant.

20. End Show Slide 20 of 32 Copyright Pearson Prentice Hall 11-1 In Mendel’s pea experiments, the male gametes are the a.eggs. b.seeds. c.pollen. d.sperm.

21. End Show Slide 21 of 32 Copyright Pearson Prentice Hall 11-1 In a cross of a true-breeding tall pea plant with a true-breeding short pea plant, the F 1 generation consists of a.all short plants. b.all tall plants. c.half tall plants and half short plants. d.all plants of intermediate height.

22. End Show Slide 22 of 32 Copyright Pearson Prentice Hall 11-1 If a particular form of a trait is always present when the allele controlling it is present, then the allele must be a.mixed. b.recessive. c.hybrid. d.dominant.

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