Unit 3 – Genetics

1. Unit 3 – Genetics I can explain the relationships between DNA and chromosomes and explain how traits are passed from parents to offspring • Today’s agenda: • Warm up • Practice correction • Power point presentation/notes

2. Warm up • A woman with type O blood is claiming that a man with type AB blood is the father of her child who is type O. Could this man be the father of the child? • Based on the information in this table, which man could not be the father of the baby? Justify your answer.

3. Warm up 3. What is mitosis? 4. What types of cells go through mitosis?

4. What do you notice about these siblings? https://www.youtube.com/watch?v=vz5bFhSEZtE

5. Sometimes siblings don’t look alike: why?

6. Prior knowledge • What is fertilization?

7. Fertilization sperm n=23 n=23 egg 2n=46 zygote • The fusion of spermand egg to form a zygote. • A zygote is a fertilized egg n=23??

8. 23 46 23 Zygote develops into embryo and finally adult organism by mitosis Fertilized egg – zygote Fertilization – process by which an egg and sperm unite Zygote – fertilized egg Embryo – organism in early stage of development

9. Mitosis produces genetically identical cells…so why are we different from our siblings (given the same biological parents)? Think Pair Share

10. Warm up – molecular genetics 1. Use the genetic code to solve this problem

11. Warm up – molecular genetics 2. Where do replication, transcription and translation take place? 3. What are the differences between RNA and DNA (3 differences)? 4. What is the cell cycle?

14. Meiosis Using scientific language, describe each phase Write down questions that come to mind

15. How is this process (meiosis) different or similar to mitosis? MITOSIS MEIOSIS

16. Review: watch the video clip and be ready to solve the problem https://www.youtube.com/watch?v=95KOL9Depuk

17. Warm up – molecular genetics 1. Use the genetic code to solve this problem: you need to give the DNA sequence, the tRNA anticodon, and the amino acid

19. Translation Overview Defined: Process of making proteins • Step 1: mRNA enters ribosome • Step 2: Ribosome reads one mRNA codon at a time • Step 3: tRNA delivers amino acids until a protein is created

20. Warm up Translate the following DNA sequence into a protein TTA GCG ACA

21. mRNA codes

22. 1. What is Arlene's genotype? • 2. What is George's genotype? • 3. What are Ann & Michael's genotypes? • 4. Most likely, Sandra's genotype is . • 5. List three people from the chart (other than George) who are most likely carriers of Falconi anemia.

23. What questions come to mind? http://slowrobot.com/i/49073

24. Meiosis Process in which diploid cells undergo two cell divisions that result in haploid cells. • Produces genetically unique cells • Results in haploid cells • Involved in sexual reproduction What does the term “diploid” mean? What’s the difference between sexual and asexual reproduction?

25. Describing Meiosis

26. Prophase I - Synapsis Homologous chromosomes sister chromatids sister chromatids Tetrad maternal paternal https://www.youtube.com/watch?v=5x_Rp1mwotQ

27. Crossing Over Tetrad nonsister chromatids P M M P M/P P/M variation chiasmata: site of crossing over http://www.youtube.com/watch?v=iCL6d0OwKt8

28. Crossing Over • Crossing over occurs between non-sister chromatids of homologous chromosomes at the chiasmata (points of crossing over) • Segments of non-sister chromatids break and reattach to the other chromatid

29. Think Why is crossing over important?

30. Crossing Over Generates Genetic Variation Tetrad nonsister chromatids P M M P M/P P/M variation chiasmata: site of crossing over http://www.youtube.com/watch?v=iCL6d0OwKt8

31. Telophase II/Cytokinesis • Meiosis II results in four non-identical haploid cells. http://www.youtube.com/watch?v=iCL6d0OwKt8

32. Video analysis As you watch the video clip, identify steps of meiosis: write down the time, example - 0:11 DNA replication (interphase) https://www.youtube.com/watch?v=iCL6d0OwKt8

33. Gametogenesis is the production of gametes Any difference between gametogenesis in males and females?

34. Gametogenesis differs between females and males • Sperm primarily contribute DNA to an embryo • Eggs contribute DNA, cytoplasm, and organelles to an embryo • During meiosis, the egg gets most of the contents; the other cells form polar bodies List some of the organelles found in a cell

35. Watch the video clip and take notes https://www.youtube.com/watch?v=VzDMG7ke69g

36. Answer the following questions • Why is meiosis called the reduction division? • What is interphase? • If you have 46 chromosomes, how many chromatides do you have? • What does it mean that meiosis produces “variety”? https://www.youtube.com/watch?v=VzDMG7ke69g

37. Review questions • How many chromosomes do germ cells have? • What do the terms “diploid” and ”haploid” mean? • If a cell with 16 chromosomes goes through mitosis, how many chromosomes will the daughter cells have?

38. More practice

39. 1. Which of these is accomplished by meiosis? Choose all that apply. • It allows multicellular organisms to get bigger in size. • It produces gametes. • It ensures even distribution of chromosomes. • It allows organisms to replace worn out cells. • It allows unicellular organisms to reproduce.

40. 2. • Meiosis 1 separates the ___. • Meiosis 2 separate the ___.

41. 3. How many total chromosomes are in a human somatic cell?

42. 4. If a somatic cell contains 50 chromosomes, • How many chromosomes are in a diploid cell? • What is the 2n number? • What is the 1n number? • How many chromosomes are in a gamete?

43. 5. How do homologous chromosomes differ from sister chromatids?

44. 6. If a haploid cell contains 30 chromosomes, • how many pairs of homologous chromosomes are there? • how many pairs of sister chromatids are there after Telophase 1? • how many pairs of sister chromatids are there after Telophase 2?

45. 7. Which of the following are true about mitosis & meiosis? Choose all that apply. • Mitosis makes identical cells; meiosis makes unique cells. • Mitosis makes haploid cells; meiosis makes diploid cells. • Mitosis makes gametes; meiosis makes somatic cells. • Mitosis makes 1 cell; meiosis makes 2 cells. • Mitosis makes cells w/ homologous chromosomes; meiosis does not.

46. 8. When & why does crossing over take place?

47. 9. What makes sexual reproduction biologically advantageous?

48. Sexual vs asexual reproduction https://www.youtube.com/watch?v=47A9-pNSYRw

49. Check for understanding What the advantages or disadvantages of sexual reproduction?

50. Mitosis & Meiosis Compared Mitosis Meiosis Location all tissues ovary/testis Products diploid somatic cells haploid egg/sperm DNA replication one round one round Cell division one round two rounds Gene recombination rare & abnormal yes (at least once per chromosome arm) Relationship between genetically identical different