Aim: What is heredity? LE1 3/25/11 Do Now: 1.Make a T Chart comparing and contrasting mitosis & meiosis. 2. Have your lab out to be collected Homework for Tuesday 3/29 Read pp. 267 270 p.270 # 1,3 Vocabulary: Character, trait,hybrid, generation, parent, offspring, "cross", heredity, inherit, pollinate, self pollinate, cross pollinate, Feb 8 8:54 AM Mar 25 1:15 PM LE3 3/25/11 LE 3 3/25/11 Mar 25 12:36 PM Mar 25 12:41 PM Aim: Who was Gregor Mendel and his role with genetics? Do Now: Look around the room. See how many different categories of traits you can list of your classmates. Homework Rd pp.267 270 p.270 # 2,3,4 Feb 8 11:34 AM Feb 8 11:46 PM 1
Mar 28 8:26 AM Mar 28 8:26 AM Aim: Who was Gregor Mendel and his role with genetics? Do Now: Look around the room. See how many different categories of traits you can list of your classmates. 809 HWK: Rd pp. 132 133 Copy summary on p.138 Homework LE 1 & 3 Rd pp.267 270 p.270 # 2,3,4 Feb 8 11:40 AM Feb 8 11:46 PM Mar 28 10:00 AM Mar 28 9:12 AM 2
Mar 28 9:14 AM Mar 28 8:44 AM Pea Plant Traits Studied by Mendel Mar 28 8:49 AM Feb 9 8:33 AM LE 3 3/28/11 Mar 28 10:13 AM Mar 28 9:34 AM 3
Genetics_2011.notebook Mar 28 9:39 AM Mar 28 9:42 AM Aim: Who was Gregor Mendel and his role with genetics? Do Now: Look around the room. See how many different categories of traits you can list of your classmates. Homework Rd pp.267 270 p.270 # 2,3,4 Mar 28 9:34 AM Feb 8 11:46 PM Aim: How are traits determined by genes? HWK 809 Complete worksheet Feb 9 10:10 AM Mar 28 12:21 PM 4
Alleles each version of a gene Genetics_2011.notebook What were the results of Mendel's Experiments? Mendelian genetics explains simple patterns of inheritance. In this pattern two versions of a gene combine and result in one of several possible traits Mendel' Pea Plant Crosses Mar 29 7:31 AM Mar 28 12:26 PM Mar 30 9:32 AM Mar 30 9:38 AM Mendel's Experiment 1. Chose plants that could self pollinate or cross breed (truebreeding) 2. Peas had many observable traits 3. Bred the plant lines for 2 years to ensure pure bred plants for particular traits He had set up a controlled experiment 4. Observed flower color: one line had white flowers, one line had purple ones Any plant in the purple flowered line when selfed or when crossed with others from the same line produced seeds that all grew into plants with purple flowers. When these plants in turn were selfed or crossed within the line, their progeny also had purple flowers, and so forth. The whiteflowered line similarly produced only white flowers through all generations. Phenotypes: the character or form for a trait that is showed a physical trait 5.The Experiment Mendel pollinated a purple flowered plant with pollen from a white flowered plant. We call the plants from the pure lines the parental generation (P). All the plants resulting from this cross had purple flowers. This progeny generation is called the first filial generation (F1 ). (The subsequent generations produced by selfing are symbolized F2, F3, and so forth.) Made reciprocal crosses: white F x Purple M white M x purple F Sex made no difference, the results were the same: If one pure breeding parent is purple flowered and the other is white flowered, all plants in the F1 have purple flowers. The purple flower color in the F1 generation is identical with that in the purple flowered parental plants. Next, Mendel self pollinated the F1 plants, allowing the pollen of each flower to fall on its own stigma. He obtained 929 pea seeds from this selfing (the F2 individuals) and planted them. Interestingly, some of the resulting plants were white flowered; the white phenotype had reappeared. Feb 9 8:38 AM Mar 28 12:27 PM 5
Mar 28 12:24 PM Mar 28 12:25 PM Mendel's principal Observations a. Dominant Recessive> characteristics of some alleles b. Law of segregation = when any individual produces gametes, the alleles separate such that each gamete gets only one member of the pair of alleles this is a universal law of independent assortment c. Law of independent assortment = alleles of different genes assort independently of one another during gamete formation (Meiosis) Law of Segregation (Dominant-Recessive) I Developing the Hypothesis a. based on observations of monohybrid crosses b. Mendel's conclusions from F1 and F2 pods: (1) "heritable factor" (Mendel didn't know about genes) for yellow pods was not lost in F1, rather, the "heritable factor" for yellow pods was "masked" by the green pod factor (2) "blending" did not occur c. Mendel did similar crosses with all 7 traits II Mendel's hypothesis of inheritance: The Law of Segregation (1) there are alternate forms of genes (alleles), the units that carry heritable characteristics (2) for each inherited characteristic, a diploid organism has two genes (alleles), one inherited from each parent (a) alleles = alternate forms of a gene that can occupy a given location (3) sperm or eggs carry only one allele for each inherited trait because the allele pairs (present on the homologous chromosomes) segregated from each other during egg/sperm production (meiosis) (4) when two alleles are different, one is fully expressed (dominant) and the other is completely masked (recessive) Feb 9 12:02 AM Feb 9 8:25 AM Mar 28 12:25 PM Mar 28 12:23 PM 6
LE 5 2/9/2010 Aim: Lab: Survey of Traits Homework Snow Day Wednesday! Complete the Lab Mar 28 12:23 PM Feb 12 7:08 AM Trait lab LE5 2/9/10 Mendel then did something that, more than anything else, marks the birth of modern genetics: he counted the numbers of plants with each phenotype. This procedure had seldom, if ever, been used in studies on inheritance before Mendel s work. Mendel counted 705 purple flowered plants and 224 white flowered plants. He noted that the ratio of 705:224 is almost exactly a 3:1 ratio (in fact, it is 3.1:1) Mendel used the terms dominant and recessive to describe this phenomenon without explaining the mechanism. The purple phenotype is dominant to the white phenotype and the white phenotype is recessive to purple. Feb 9 11:49 AM Feb 9 8:55 AM he counted the numbers of plants with each phenotype. This procedure had seldom, if ever, been used in studies on inheritance before Mendel s work. Mendel counted 705 purple flowered plants and 224 white flowered plants. He noted that the ratio of 705:224 is almost exactly a 3:1 ratio (in fact, it is 3.1:1). Mendel used the terms dominant and recessive to describe this phenomenon without explaining the mechanism. The purple phenotype is dominant to the white phenotype and the white phenotype is recessive to purple. Feb 9 8:55 AM Feb 9 9:32 AM 7
Genetics_2011.notebook Aim: What is Mendel's Law of Segregation? Do Now: Explain what a phenotype is. Feb 9 8:25 AM Feb 8 11:52 PM uk Genetics Vocabulary Allele one of the alternative forms of a gene that governs a characteristic. Ex. Hair color Dominant describes an allele that is fully expressed whenever the allele is present in an individual Recessive an allele that is expressed only when there is no dominant allele for that trait present in an individual both alleles must be recessive to express the trait Phenotype an organism's appearance or other detectable characteristic that results from the organism's genotype & environment Genotype a specific combination of alleles in an individual Heterozygous (Hybrid) describes an individual that carries two different alleles of a gene Homozygous(Pure) an individual that has identical alleles for a trait Feb 12 8:53 AM Feb 12 12:00 PM Feb 12 9:39 AM Feb 12 9:42 AM 8
Feb 12 9:56 AM Feb 12 10:08 AM 2/23/2010 Aim: How can Punnett Squares be used to predict traits? 1. true breeding strain = strain (variety) that, when self fertilized, only produces offspring with the given trait are homozygous for the trait Do Now: What is the difference between a phenotype and a genotype? 2. P generation = the parental generation in a cross 3. F1 generation = first filial generation = first offspring of the p generation 4. F2 generation = 2nd filial generation = offspring of the F1 generation 5. alleles = alternate forms of a specific gene Homework Feb 9 12:00 AM Feb 8 11:53 AM Inheritance of Albinism A recessive Trait The pigment melanin contributes to the color of skin, eyes and hair. Some people have the hereditary condition, albinism; they are not able to produce melanin and have little or no pigment in their skin and hair. One allele of this gene codes for melanin production and normally pigmented skin and hair; it is symbolized by A. Another allele of this gene codes for albinism; it is symbolized by a. Feb 8 11:55 PM Feb 8 11:12 PM 9
1. What fraction of this couple's children would you expect to be AA? 2. What fraction of this couple's children would you expect to be Aa? 3. What fraction of this couple's children would you expect to be aa? 4. What fraction of this couple's children would you expect to have normal pigmentation? 5. What fraction of this couple's children would you expect to have albinism? Feb 8 11:34 AM 10