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January 16, 2013. (A Day) Agenda DSJ #19 Genetics: Dominant and Recessive Alleles (Notes) Simple Genetics Problems (Worksheet) DSR #19. January 17, 2013. (B Day) Agenda DSJ #19 Genetics: Dominant and Recessive Alleles (Notes) Simple Genetics Problems (Worksheet) DSR #19. DSJ #19.
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January 16, 2013 (A Day) Agenda • DSJ #19 • Genetics: Dominant and Recessive Alleles (Notes) • Simple Genetics Problems (Worksheet) • DSR #19
January 17, 2013 (B Day) Agenda • DSJ #19 • Genetics: Dominant and Recessive Alleles (Notes) • Simple Genetics Problems (Worksheet) • DSR #19
DSJ #19 Science Notebook – Page 40B Prompt: When Mendel crossed a tall pea plant with a short pea plant, the result was an entire generation of tall plants. But when those plants self-pollinated, it resulted in the next generation having a mix of both tall and short plants. In 5 sentences or more, describe why you think the short trait “skipped” a generation.
Learning Objective • Students will know what alleles are and the two types of alleles.
Dominant and Recessive Alleles • Genes are the factors that control a trait. • Alleles are the different forms of a gene.
Dominant and Recessive Alleles • A trait controlled by a dominant allele always shows up in the organism when the allele is present. • So, a recessive allele will be masked when a dominant allele is present
Dominant and Recessive Alleles 11. A recessive trait will only show up if both alleles are recessive.
Hybrids 12. 13. & 14. • The plants both contain dominant and recessive alleles. Dominant Recessive • But why are they both tall?
Symbols for Alleles 15. A dominant allele is represented by a capital letter. 16. A recessive allele is represented by the lower case version of the letter . • For example, the allele for tall stems is represented by: • T • For example, the allele for short stems is represented by: • t
Symbols for Alleles 17. TT tt Tt Tt
Significance of Mendel’s Work • People used to think that if you mixed traits you would have a blended form. If this were true, all of Mendel’s pea plants would have a medium height. • Mendel’s work wasn’t recognized in his lifetime. • But, in 1900 three different scientists discovered his work and recognized the importance of his ideas. 18. Because of this, he is often called the Father of Genetics.
Glue in SNB • 40A - Genetics: Dominant and Recessive Alleles (Notes) • 41B – Simple Genetics Problems
DSR #19 • Science Notebook – Page 40B (Under DSJ #19) • Prompt: What is a dominant allele and what is it represented by? What is a recessive allele and what is it represented by? What kind of alleles does a hybrid organism have?