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Key Vocabulary

Genetics: Mendell: 11/11/2019 Objectives: SWBAT explain the importance of Gregor Mendell’s work by examining its relevance to modern day genetics through completing Punnet Squares. Drill: 1. How many chromosomes does a person with Down’s Syndrome have?. Key Vocabulary.

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Key Vocabulary

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  1. Genetics: Mendell: 11/11/2019Objectives:SWBAT explain the importance of Gregor Mendell’s work by examining its relevance to modern day genetics through completing Punnet Squares.Drill: 1. How many chromosomes does a person with Down’s Syndrome have?

  2. Key Vocabulary • Fill in the vocabulary on the back of your drill sheet.

  3. Key Vocabulary • Genetics: the study of heredity • Homozygous: 2 of the same alleles • Heterozygous: 2 different alleles • Allele: 1 of 2 forms of a gene • Genotype: the genetic characteristics • Phenotype: the physical characteristics

  4. Key Vocabulary • Dominant: the trait that will be shown if present • Recessive: a trait that will only be seen if no dominant traits are present. • Probability: The chance something will happen

  5. Gregor Mendell • Read over the introductory paragraph about Gregor Mendell. • Define the vocabulary words. • Complete the Steps of Mendell’s experiments worksheet as a class. • Let’s look at how we can use repeat and use Mendell’s experiments.

  6. Genetics&The Work of Mendel

  7. Gregor Mendel • Modern genetics began in the mid-1800s in an abbey garden, where a monk named Gregor Mendel documented inheritance in peas • used experimental method • usedquantitative analysis • collected data & counted them • excellent example of scientific method

  8. He studied at the University of Vienna from 1851 to 1853 where he was influenced by a physicist who encouraged experimentation and the application of mathematics to science and a botanist who aroused Mendel’s interest in the causes of variation in plants. After the university, Mendel taught at the Brunn Modern School and lived in the local monastery.

  9. The monks at this monastery had a long tradition of interest in the breeding of plants, including peas. Around 1857, Mendel began breeding garden peas to study inheritance.

  10. Mendel’s work Pollen transferred from white flower to stigma of purple flower P • Bred pea plants • cross-pollinate true breeding parents (P) • P = parental • raised seed & then observed traits (F1) • F = filial • allowed offspring to self-pollinate& observed next generation (F2) anthers removed all purple flowers result F1 self-pollinate F2

  11. Mendel collected data for 7 pea traits

  12. true-breeding purple-flower peas true-breeding white-flower peas 100% purple-flower peas F1 generation (hybrids) 100% 75% purple-flower peas 25% white-flower peas 3:1 F2 generation Looking closer at Mendel’s work X P Where did the whiteflowers go? Whiteflowers cameback! self-pollinate

  13. What did Mendel’s findings mean? • 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

  14. Traits are inherited as discrete units • 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 theadvantages ofbeing diploid?

  15. What did Mendel’s findings mean? I’ll speak for both of us! • Some traits mask others • purple & white flower colors are separate traits that do not blend • purple x white ≠ light purple • purplemaskedwhite • dominant allele • functional protein • masks other alleles • recessive allele • allele makes a malfunctioning protein mutantallele producingmalfunctioningprotein wild typeallele producingfunctional protein homologouschromosomes

  16. X P purple white F1 all purple Genotype vs. phenotype • Difference between how an organism “looks” & its genetics • phenotype • description of an organism’s trait • the “physical” • genotype • description of an organism’s genetic makeup Explain Mendel’s results using …dominant&recessive …phenotype&genotype

  17. PP pp x X P purple white F1 all purple Making crosses • Can represent alleles as letters • flower color alleles  P or p • true-breeding purple-flower peas  PP • true-breeding white-flower peas  pp Pp

  18. true-breeding purple-flower peas true-breeding white-flower peas 100% purple-flower peas F1 generation (hybrids) 100% 75% purple-flower peas 25% white-flower peas Looking closer at Mendel’s work phenotype X P PP pp genotype Pp Pp Pp Pp self-pollinate 3:1 F2 generation ? ? ? ?

  19. PP 25% male / sperm P p Pp 50% 75% P Pp female / eggs pp p 25% 25% Aaaaah, phenotype & genotypecan have different ratios Punnett squares F1 generation (hybrids) Pp x Pp % genotype % phenotype PP Pp Pp pp 1:2:1 3:1

  20. Genotypes • Homozygous = same alleles = PP, pp • Heterozygous = different alleles = Pp homozygousdominant heterozygous homozygousrecessive

  21. purple PP homozygous dominant purple Pp heterozygous How do you determine the genotype of an individual withwith a dominant phenotype? Phenotype vs. genotype • 2 organisms can have the same phenotype but have different genotypes Can’t tellby lookin’at ya!

  22. The Steps • P generation: Parental generation (pure) • F1: First Filial generation (1=first) • F2: Second Filial generation (2=second)

  23. Gregor Mendell • Genetics: The study of inheritance • Dominant: the strongest gene • Recessive: only appears when the dominant is not present • Probability: is the chance something will happen (the chance of a certain trait)

  24. Repeating and Interpreting • Pure purple (WW): homozygous dominant • Pure white (ww): homozygous recessive

  25. Punnet Square W (purple) W (purple) w white w white W W w w W w W w

  26. Repeating and Interpreting • All of the F1 (children) are heterozygous for the gene for flower color

  27. Blue=phenotype Red=Genotype W w Purple=75% W w W W W w WW=25% Ww=50% white=25% W w w w Ww=50% ww=25%

  28. Tongue Curling Warm-Up Review Punnett Squares by completing this worksheet individually. QUESTIONS, please raise your hand.

  29. Genotypic ratio: WW=25% (1/4) Ww=50% (2/4) ww=25% 1/4 Phenotypic ratio: Purple=75% (3/4) white = 25% (1/4)

  30. 3, 1, 4, 2 • Alleles for the parents • Genotypes (alleles) for offspring

  31. Objectives:SWBAT demonstrate an understanding of DNA by successfully completing the DNA Mega-QuizSWBAT explain the importance of Gregor Mendell’s work by examining its relevance to modern day genetics.Drill:1. Is this homozygous or heterozygous? 2. If “A” stands for straight hair and “a” stands for curly hair, what kind of hair will the person have? Aa

  32. Drill:1. Is this homozygous or heterozygous?2. If “A” stands for straight hair and “a” stands for curly hair, what kind of hair will the person have? Aa heterozygous Straight

  33. Key Vocabulary • Homozygous: 2 of the same alleles AA or aa • Heterozygous: 2 different alleles Aa

  34. Homework & Quiz Dates • Homework #5: W 2/28 Homework #6: M 3/5 Homework #7: F 3/9 Quiz #3: Th 3/1 Quiz #4: Th 3/8 

  35. Punnett Squares II • Let’s walk through these two problems together. • Questions, you will now try these in your Punnett Squares Scenarios packet.

  36. Punnett Squares Scenarios • Work with a partner to answer these questions. • Raise your hand if you get stuck.

  37. Critical Reading a. To show the probability of the offspring b. Both parents have two different alleles (Bb) c. Both parents are Bb and B is dominant- so both are black.

  38. Critical Reading • BB & bb • 1 BB: 2Bb: 1bb (25%BB: 50%Bb: 25%bb) • B 3: b 1 (Black:3 brown: 1) 2. Shows the physical characteristics 3. d. Phenotypic ratio

  39. Curling your tongue warm-up C C C c c c C c C c C c

  40. Curling your tongue warm-up C C C c c c C c C c C c

  41. Curling your tongue warm-up R r R r R r R r R r R r

  42. Punnett Squares Scenarios A person who studies how traits are passed on is studying genetics. Long rod shaped bodies inside a cell’s nucleus are called chromosomes. Chromosomes have parts that determine traits. These parts are genes.

  43. Punnett Squares Scenarios An organism having two genes that are alike is said to be pure, however if the organism has one dominant and one recessive gene for a trait, it is called heterozygous. The gene that is dominant prevents the other gene from showing. One method for showing which genes can combine when an egg and sperm join is a Punnett square.

  44. Punnett Squares Scenarios M e dd F Nn i AA g KK L oo Ff ll W Cc tt B zZ ss Pu E R SS p

  45. Punnett Squares Scenarios He: Heterozygous Ho-D: Homozygous Dominant Ho-r: Homozygous Recessive Genotypic Ratio: (the letters) DD :0/4 Dd:2/4 dd:2/4 (Ho-D) (He) (Ho-r)

  46. Punnett Squares Scenarios He: Heterozygous Ho-D: Homozygous Dominant Ho-r: Homozygous Recessive Phenotypic Ratio: (what it looks like) DD & Dd=Dimples dd=no dimples 50% 50%

  47. Punnett Squares Scenarios Genotype Homozygous AA Dominant Heterozygous Aa Homozygous aa Recessive Phenotype dominate trait recessivetrait

  48. Give an example of a homozygous recessive genotype with Q • Give an example of a heterozygous genotype with Q. • Cross 2 Heterozygous for the letter R (round ears) (r=pointy) • What is the genotypic ratio for #3? • What is the phenotypic ratio for #3?

  49. Genetics: Punnett Squares: 11/11/2019Objectives:SWBAT explain the importance of genetics by examining its relevance to inheritance through completing Punnett Squares.Drill:1. Is this homozygous or heterozygous? 2. If this person mates with a person with “Bb” what percent of their children will be heterozygous? BB

  50. BB: Homozygous Bb: Heterozygous B B B B B b B B B b B b

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