Catalyst

1. Catalyst • Catalyst: Copy and answer the following questions • What are your goals for second semester? • What are your expectations of me? • What expectations should I have of you?

2. Expectations • All homework will be completed on time. • All work will be completed in blue or black ink. • All lab reports will be typed. • Students will bring their own supplies (including tissues).

3. Genetics: The Who and What of Us What is genetics? Where exactly on a DNA molecule are genes located? Is it possible to remove DNA from a cell? Are there any ethical questions concerning genetics?

4. Introduction to Genetics • What is genetics? • Genetics is the study of heredity (the passing of traits from one generation to the next. • Traits are physical characteristics (eye and hair color, size, facial features, etc.) • Traits are controlled by genes

5. Introduction to Genetics • Where exactly are genes located? • Genes are located on strands of DNA • DNA is a long molecule shaped like a twisted staircase (double helix)

6. Introduction to Genetics • Each step contains a pair of nitrogen bases (A, T, G, C) • Genes are composed of a series of nitrogen base pairs (codes)

7. Introduction to Genetics E. The average gene is 2,000-200,000 base pairs long F. Animal and plant cells contain thousands of genes

8. Catalyst • Get out cloning article. • Catalyst: Copy and answer the following question: Please summarize what we discussed yesterday in class concerning anything you learned about the study of genetics.

9. Introduction to Genetics • Where exactly are genes located? • Genes are located on strands of DNA • DNA is a long molecule shaped like a twisted staircase (double helix)

10. Introduction to Genetics • Each step contains a pair of nitrogen bases (A, T, G, C) • Genes are composed of a series of nitrogen base pairs (codes)

11. Introduction to Genetics E. The average gene is 2,000-200,000 base pairs long F. Animal and plant cells contain thousands of genes

12. Reading Quiz • How is cloning different from the way animals and plants normally reproduce? • What are some of the complications (problems) with cloning? (in other words, why doesn’t cloning always work?) • Ethically speaking, what is your stance on cloned meat? Should stores sell it or not?

13. Do Now • Enter quietly and submit your homework • Do now: Assuming the kittens in the picture are full siblings, why does only one have black markings while the rest have brown?

14. Genetics: The Who and What of Us Who was Gregor Mendel? Who likes peas anyway?

15. Gregor Mendel • Who was Gregor Mendel • A monk who lived during the mid-1800’s in Germany • Experimented with peas and ended up with the title: “Father of Genetics”

16. Gregor Mendel 2. Who likes peas anyway? • Mendel did an experiment where he crossbred two purebred pea plants. • The two pea plants were exactly alike, except one was tall and one was short. • Gene: Height • Alleles: Tall and short

17. Gregor Mendel • Mendel was shocked by the results. The offspring (F1 generation) were all tall… • Mendel decides, of course to repeat the experiment—but this time, he combines to of the pea plants from the F1 generation

18. Gregor Mendel • The results? 75% of the F2 generation were tall. 25% of the F2 generation were short • Mendel repeated the experiment with many other traits (color, shape, etc)…but the results were always the same

19. Gregor Mendel • Homework: Explain Mendel’s results. Use page 73 to help you explain why Mendel’s F1 generation were all tall but the F2 generation was only 75% tall and 25% short. (include the words allele, gene, dominant, and recessive)

20. Catalyst • Enter quietly and submit your homework • Catalyst: Summarize the information we discussed in class last Thursday.

21. Genetics: The Who and What of Us What is the difference between dominant and recessive alleles? What is the difference between genotype and phenotype? Is it possible to predict the outcomes of a genetic cross?

22. Dominant v. Recessive Alleles • An allele is a form of a gene • Some alleles are dominant (will exhibit themselves); ex: tall allele in bean plants • Some alleles are recessive (will not exhibit themselves); ex: short allele in bean plants • Dominant and recessive genes are written using symbols; ex: tall (T) and short (t)

23. Dominant v. Recessive Alleles • Organisms have two alleles for each gene (one from each parent). • Homozygous organisms have two identical alleles • Heterozygous organisms have two different alleles

24. Genotype v. Phenotype • An organism’s phenotype (the way it looks) is determined by the allele that is dominant • An organism’s genotype (its genetic makeup) consists of both dominant and recessive alleles

25. Practice • Assume that brown eyes are dominant and blue eyes are recessive: • What symbols would you use to represent brown eyes? Blue eyes? • If an individual has brown eyes, what possible eye color alleles could make up the individual’s genotype? • What is the phenotype of an individual with the genotype bb?

26. Practice 2. Assume that curly hair is dominant and straight hair is recessive: • What symbols would you use to represent curly hair? Straight hair? • If an individual has curly hair, what possible eye color alleles could make up the individual’s genotype? • What is the phenotype of an individual with the genotype Cc?

27. Do Now • Enter quietly and submit your homework (Article Review). • Get out the “Understanding Mendel’s Results” handout • Do now: What is the difference between an organism’s phenotype and an organism’s genotype? Give an example.

28. Genetics: The Who and What of Us Why was Mendel’s F2 generation 75% tall and 25% short? (bean experiment) Is it possible to predict the phenotype and genotype of a genetic cross?

29. Understanding Mendel’s Results • Because all members of the F1 generation had the same genotype (Bb), each member also had the same phenotype (brown) 2. Because members of the F2 generation had different genotypes (BB, Bb, or bb), members had different phenotypes (brown or white)

30. Understanding Mendel’s Results 3. Because brown is dominant, the majority of F2 plants were brown. A plant could only be white if it received 2 white alleles (bb). 4. On average, 75% of F2 plants exhibited a brown phenotype, while 25% exhibited a white phenotype Punnett Square

31. Predicting Genotype/Phenotype • A Punnett Square is a chart that shows all the possible outcomes of a genetic cross and to determine the probability of a particular outcome

32. Do Now • Enter quietly and get out your science fair packet • Do now: What is the probability that the offspring of a person with heterozygous dominant brown eyes (Bb) and a person with homozygous recessive blue eyes (bb) will be blue?

33. Agenda • I will be conferencing with each of you about science fair. • You will independently work on: • Family album project • Filling in your vocabulary sheets/studying for the test (next Friday) • Science fair • Extra credit (read page 109-113, #1-4)

34. Do Now • Enter quietly and get out your completed family albums • Do now: What is the probability that the offspring of a person with homozygous recessive no freckles (ff) and a person with heterozygous dominant freckles (Ff) will have freckles?

35. Agenda • Review Do Now • Present homework • Review notes • Jeopardy • Study guide

36. Genetics: The Who and What of Us The structure of DNA and the location of genes Offspring receive half their genetic material from each parent Most people’s genes have two forms (alleles). Alleles may be recessive or dominant

37. DNA and Genes 1. DNA and genes • Genes are located on strands of DNA which are in the shape of a double helix • DNA strands contain nitrogen bases • Genes are constructed from a series of nitrogen bases

38. Dominant v. Recessive Alleles • An allele is a form of a gene • Organisms have two alleles for each gene (one from each parent). • Homozygous organisms have two identical alleles • Heterozygous organisms have two different alleles • An organism’s phenotype is determined by the allele that is dominant • An organism’s genotype consists of both dominant and recessive alleles

39. Jeopardy • Which of the following is false? • The cell of an organism usually contains two alleles • All alleles express themselves • An allele is a form of a gene • Only eukaryotic cells contain chromosomes

40. Jeopardy • What is DNA? • A molecule shaped like a double helix • The genetic material of living organisms • A chromosome • A and B

41. Jeopardy • Where are genes? • Genes are a series of nitrogen bases located on a strand of DNA • Outside the nucleus • Inside a strand of nitrogen bases • Wrapped on top of a double helix

42. Jeopardy 4. What occurs during prophase? • Chromatin condenses into chromosomes • Chromatin copies itself • Chromosomes line up in the center of the cell • The nucleus divides

43. Jeopardy • Why does DNA copy itself during interphase? • To make an extra copy of DNA in case the original set gets destroyed • To replace damaged sections • To make sure that daughter cells are exact genetic copies of the parent cell • None of the above

44. Jeopardy 6. Which of the following could be an accurate interpretation of the genotype Rr? • Homozygous recessive red hair • Homozygous dominant red hair • Heterozygous recessive red hair • Heterozygous dominant red hair

45. Jeopardy 7. Which of the following could be an accurate interpretation of the genotype RR? • Homozygous recessive red hair • Homozygous dominant red hair • Heterozygous recessive red hair • Heterozygous dominant red hair

46. Jeopardy • A genotype describes a cell’s _____ while phenotype describes ______ • Appearance, genetic makeup • Genetic makeup, appearance • Genetic makeup, allele combinations • Allele combinations, genetic makeup

47. Jeopardy 9. Which of the following could be the genotype of an individual with heterozygous dominant brown eyes? • Bb • bb • BB • Brown

48. Jeopardy 10. What are the chances that a baby’s eyes will be blue if the mother has homozygous recessive blue eyes (bb) and the father has heterozygous dominant brown eyes (Bb)? • 25% • 50% • 75% • 100%

49. Jeopardy 11. Who was Gregor Mendel? • Father of genetics • Discoverer of dominant and recessive alleles • Friend of pea plants • All of the above

50. Jeopardy 12. What do twins and clones have in common? • They were both created in a laboratory • They have the same personalities • They have identical genes • Both B and C