2 24 Intro To Punnet Squares


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2 24 Intro To Punnet Squares

  1. 1. Launch <ul><li>Correct the following false statements to make them true statements: </li></ul><ul><li>“ We write the haploid number as 4N” </li></ul><ul><li>“ Somatic cells and sex cells both undergo meiosis” </li></ul><ul><li>“ An example of a somatic cell is eggs” </li></ul><ul><li>“ An example of a germline cell is a brain cell” </li></ul>
  2. 2. Mendelian Genetics
  3. 3. Mendelian Genetics <ul><li>Mendelian Genetics is the study of how traits are passed down from parents to offspring </li></ul>
  4. 4. Father of Genetics <ul><li>Gregor Mendel is considered to be the </li></ul><ul><li>father of genetics </li></ul><ul><li>Gregor Mendel was an Austrian priest who made a lot of scientific discoveries about inheritance by studying peas and flowers. </li></ul>
  5. 5. Inheritance <ul><li>Inheritance is the passing of traits from parents to offspring </li></ul>
  6. 6. Gene <ul><li>A certain portion of DNA that codes for a specific protein </li></ul><ul><ul><li>Ex: Genes for hair color, eye color, hormones, etc. </li></ul></ul><ul><li>The rest of DNA is known as junk DNA. </li></ul>
  7. 7. Gene <ul><li>Some traits are complex and require multiple genes </li></ul><ul><ul><li>Skin color </li></ul></ul>
  8. 8. Allele <ul><li>Alleles are different forms of one gene. </li></ul><ul><ul><li>Example: </li></ul></ul><ul><ul><ul><li>The gene is hair color </li></ul></ul></ul><ul><ul><ul><li>The alleles might be brown hair, blonde hair, red hair, black hair, etc. </li></ul></ul></ul>
  9. 9. Genotype <ul><li>The genotype is the way we describe the genetic make-up of an individual. </li></ul><ul><li>The genotype always consists of two letters: one for the allele from the mother, one for the allele from the father </li></ul><ul><ul><li>Rr, SS, dd </li></ul></ul>
  10. 10. Phenotype <ul><li>The phenotype is the physical appearance that is made as the result of an individual’s genotype. </li></ul><ul><ul><li>The things we see! </li></ul></ul>
  11. 11. Genotype <ul><li>Alleles are either dominant or recessive . </li></ul><ul><li>When a dominant allele is present, you only see the dominant phenotype even if the recessive allele is also present. </li></ul><ul><li>Hh </li></ul>
  12. 12. Dominant <ul><li>Dominant genes only require one allele to express the dominant phenotype. </li></ul><ul><li>Dominant alleles are represented in genotypes with a capital letter. </li></ul><ul><li>Examples: HH, Dd, SS, Tt, </li></ul>
  13. 13. Recessive <ul><li>Recessive genes require both alleles to express the recessive phenotype. </li></ul><ul><li>Recessive alleles are represented in genotypes with a lower case letter. </li></ul><ul><li>Examples: hh, dd, ss, tt, </li></ul>
  14. 14. Heterozygous <ul><li>Individuals are heterozygous for a gene when they receive a dominant allele from one parent and a recessive allele from another parent. </li></ul><ul><ul><li>Rr, Ss, Tt, Uu </li></ul></ul>
  15. 15. Think-Pair-Share <ul><li>Why do individuals heterozygous for a gene always produce a dominant phenotype? </li></ul>
  16. 16. Homozygous <ul><li>Individuals are homozygous when they receive the same allele from both parents </li></ul><ul><ul><li>Individuals are either homozygous dominant or homozygous recessive </li></ul></ul><ul><ul><ul><li>RR, rr, SS, ss </li></ul></ul></ul>
  17. 17. Exit Slip <ul><li>__________ do mitosis, __________ do meiosis </li></ul><ul><ul><li>A. brains cells, heart cells </li></ul></ul><ul><ul><li>B. eggs, sperm </li></ul></ul><ul><ul><li>C. sperm, brain cells </li></ul></ul><ul><ul><li>D. brain cells, eggs </li></ul></ul><ul><li>If an individual is “Hh” for a trait </li></ul><ul><ul><li>Is this individual homozygous or heterzygous? </li></ul></ul><ul><ul><li>Have a dominant or recessive trait? </li></ul></ul>