BIOL 240 1st Edition Lecture 3Outline of Last Lecture I. Meiosis III. Meiosis IIIII. SpermatogenesisIV. OogenesisOutline of Current Lecture I. Mendel’s experiment1. Why peas?2. Experimented characteristics3. Monohybrid crosses4. ConclusionsII. Genetic Terminology1. Phenotype2. Genotype3. Gene4. AlleleCurrent LectureI. Mendel’s experiment1. Why peas? Mendel chose to experiment with peas because they are easy to grow, possible to control self-fertilization or cross-fertilization, and they have observable and distinguishable characterisitcs.2. Experimented characteristics:a. Seed shape (round or wrinkled)b. Seed color (green or yellow)c. Pod shape (full or constricted)d. Pod color (green or yellow)e. Flower color (violet or white)f. Flower position (axial or terminal)g. Stem height (tall or dwarf)3. Controlled monohybrid crossesa. These crosses involved pairs of true breeding plants with only one differing characteristic. The first generation were true breeding (DD and dd) and were crossed. Their offspring resulted in all dominant characteristics (Dd), masking These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.the recessive (dd). These were crossed and their offspring resulted in ¾ dominant and ¼ recessive; a 3:1 ratio. A visual is given below.b. Mendel discovered that reciprocal crosses gave the same result and sex is independent of the results.4. Mendel’s conclusionsa. Heredity is controlled by genes and traits are passed unchanged through generationsb. Organisms have two copies of each gene (alleles)- one from the mother and one from the fatherc. In the case that two alleles an organism has are different, one is dominant and the other is recessive.d. Law of Segregation: alleles separate and enter different gametes; gametes only receive one allele of each pairII. Genetic Terminology1. Phenotype- the physical representation of a trait2. Genotype- alleles or genetic makeup; homozygous (DD, dd) or heterozygous (Dd)3. Gene- located on chromosomes; carries alleles of a trait4. Allele- single gene received from each
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