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Biology 102A

Biology 102A. Genetics Unit Day One. Journal 1. On a clean sheet of paper, respond to the following: Write down 3 things you already know about genetics (inheritance, punnett squares, genetic traits, pedigrees, gene mutations, genetic disorders).

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Biology 102A

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  1. Biology 102A Genetics Unit Day One

  2. Journal 1 • On a clean sheet of paper, respond to the following: • Write down 3 things you already know about genetics (inheritance, punnett squares, genetic traits, pedigrees, gene mutations, genetic disorders). • Write down 3 things you would like to know about genetics

  3. Define heredity & genetics. (11-1) • Heredity: the passing of characteristics (traits) from parents to offspring • Genetics: the study of heredity

  4. Describe the work of Gregor Mendel • Gregor Mendel was the first person to predict how traits are transferred from parent to offspring; called the “Father of Genetics” • Austrian monk in the 1830’s who was in charge of the monastery garden • Decided to study how traits were passed in garden peas

  5. Gregor Mendel • Why peas? Reproduce sexually, gametes are found on the same flower, and fertilization could be controlled by pollination • Mendel transferred pollen from plant to plant and studied the resulting offspring pea plants • Mendel removed the male parts of the flowers to prevent uncontrolled pollination

  6. Gregor Mendel • Mendel collected both quantitative data and qualitative data: counts and descriptions • Mendel studied only one trait at a time (height, flower color, pea color, etc.) • Mendel worked with true-breeders at first; those that would only produce one type of offspring • Then he crossed them to produce the first generation of HYBRIDS (F1 generation) • F1 generation only resembled one of the parents

  7. Mendel’s conclusions • First Conclusion: inheritance is determined by factors passed from parent to offspring (today these are called GENES) • The different forms of genes are called alleles (ex: for color gene there are two forms: one for black and one for white)

  8. Mendel’s conclusions • Second conclusion: Principle of dominance • Some alleles are dominant and others are recessive • Recessive traits can be hidden whenever a dominant allele is present • Dominant alleles are represented by capital letters • Recessive alleles are represented by lowercase letters; in order to display a recessive trait, two recessive alleles must be present

  9. Mendel’s questions about segregation. • Mendel wanted to know if the recessive traits had disappeared or were they still present in the plants? • Mendel allowed the hybrids to breed and observed the offspring’s traits, the recessive trait showed up again!(F2 generation) • Mendel concluded that the alleles for traits were separated during the formation of gametes; this is segregation • Each gamete carries a single copy of each gene

  10. Define probability. • The chance or percent chance of a trait being exhibited • Principles of probability can be used to predict the outcomes of genetic crosses

  11. Quiz 1 • The study of how traits are passed from parent to offspring is called? a. genetics b. heredity c. mendelism • What is the proper way to indicate a dominant trait? a. d b. dd c. D • The result of mixing two true-breeders is called a ? a. mutant b. factor c. hybrid • What are Mendel’s inherited “factors” called today? a. traits b. genes c. they are still called factors • What is the probability of having a boy or girl with each pregnancy? a. 100 % b. 75% c. 50% d. 25% **

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