2. Biology Unit 6 / Chapter 11 Powerpoint #1 Mr. Velekei

3. 1. Allele 2. Cross pollination 3. Gene 4. Genetics 5. Hybrid 6. Self pollination 7. Trait 8. True breeding

4. Gregor Mendel was born in 1822 in the Czech Republic Studied Science and Mathematics at the University of Vienna Spent the next 14 years teaching high school and working at a monastery in the garden

5. Mendel noticed that the SAME type of plant could have VARIATIONS, or differences, these are the variations he noticed: Seed ShapeSeed ColorSeed Coat Color RoundYellowGray WrinkledGreenWhite Pod ShapePod ColorFlower PositionPlant Height SmoothGreenAxialTall ConstrictedYellowTerminalShort

7. AFTER MENDEL NOTICED THESE VARIATIONS HE DECIDED TO DO AN EXPERIMENT OF HIS OWN.  Mendel wanted to breed the pea plants together in different combinations to see what the offspring (seedlings) would look like.  used experimental method  used quantitative analysis  collected data & counted them  excellent example of scientific method

10. Genetics: study of heredity (how traits pass from one generation to the next) True-breeding: if allowed to self-pollinate, produce offspring identical to self Self-pollination: pollen from one flower fertilizes egg cells in same flower Cross-pollination: pollen from one flower fertilizes egg cells in a different flower

11. Pollen transferred from white flower to stigma of purple flower anthers removed all purple flowers result F1F1 P F2F2 self-pollinate  Bred pea plants  cross-pollinate true breeding parents (P)  P = parental  raised seed & then observed traits (F 1 )  F = filial  allowed offspring to self-pollinate & observed next generation (F 2 )

12. Describe how Mendel prevented self- pollination and controlled cross-pollination in pea plants: He cut off the male parts (anthers) of one flower, then dusted the stigma with pollen from a second flower. Why did he want to do this? He wanted plants with specific traits to breed with one another.

13. F 2 generation 3:1 75% purple-flower peas 25% white-flower peas P 100% F 1 generation (hybrids) 100% purple-flower peas X true-breeding purple-flower peas true-breeding white-flower peas self-pollinate Where did the white flowers go? White flowers came back!

14.  Traits come in alternative versions  purple vs. white flower color  alleles  different alleles vary in the sequence of nucleotides at the specific locus of a gene  some difference in sequence of A, T, C, G purple-flower allele & white-flower allele are two DNA variations at flower-color locus different versions of gene at same location on homologous chromosomes

15.  For each characteristic, an organism inherits 2 alleles, 1 from each parent  diploid organism  inherits 2 sets of chromosomes, 1 from each parent  homologous chromosomes  like having 2 editions of encyclopedia  Encyclopedia Britannica  Encyclopedia Americana What are the advantages of being diploid?

16.  Some traits mask others  purple & white flower colors are separate traits that do not blend  purple x white ≠ light purple  purple masked white  dominant allele  functional protein  masks other alleles  recessive allele  allele makes a malfunctioning protein  masked by the dominant allele homologous chromosomes I ’ ll speak for both of us! wild type allele producing functional protein mutant allele producing malfunctioning protein

17.  Principle of dominance: dominant trait is always seen when dominant allele is present; recessive trait is only seen when no dominant allele is present

18. 1. In the first generation of each experiment, how do the characteristics of the offspring compare to the parents’ characteristics? 2. How do the characteristics of the second generation compare to the characteristics of the first generation? 3. How do we know the recessive allele did not disappear? Parents Long stems  short stems Red flowers  white flowers Green pods  yellow pods Round seeds  wrinkled seeds Yellow seeds  green seeds First Generation All long All red All green All round All yellow Second Generation 787 long: 277 short 705 red: 224 white 428 green: 152 yellow 5474 round: 1850 wrinkled 6022 yellow: 2001 green