Exam 2 Q3 Review Sheet Honors Biology Exam 2 Q3 will cover: Chapter 9: Intro through 9.9 1. Explain why cancer is genetic, but not inherited. A predisposition to cancer can be inherited. How is this possible on the gene level? 2. Describe what is meant by nature vs. nurture. 3. Explain the MAOA experiment. What is the importance of the results of this experiment? 4. Identical twins are genetically identical. However, there are notable differences between the two siblings. How is this possible? 5. Certain diseases like Tay-Sachs and cystic fibrosis are purely genetic. What does this mean? Give an example of a trait that is completely environmental. 6. Identify the two contributing factors that make you who you are. 7. Compare and contrast pangenesis, the blending hypothesis and Mendelian genetics. 8. Who was Gregor Mendel? Describe his job, background, etc… 9. Explain the three keys to the success of Gregor Mendel. Know how he did his experiments. 10. What made the pea plant a great model organism for study? 11. How did Mendel control the mating in his experiments? 12. What was so special about the traits he chose to observe? 13. In class we looked at an image of two engines, one made of a few blocks of wood and some wire, and another from a modern day sports car. Which would you study to try and figure out how an engine works? Explain why. 14. What did Mendel know about genes, chromosomes, DNA and evolution? 15. Explain why Mendel began by self-fertilizing purple flower plants until he got strains that only produced purple flowers, and the same for white flower plants? What are these breeds called? 16. What is meant by a monohybrid cross? 17. Be able to describe Mendel’s monohybrid cross between true-breed purple and truebreed white flowering plants in detail. Why do you think he chose to self-fertilize the F1 generation hybrids? What was he looking for? 18. Describe Mendel’s four hypotheses based on this simple monohybrid experiment. Make sure you know what the principle of segregation states in detail on the chromosomal level! 19. How do his four hypotheses relate to what you know today about genes and chromosomes? You should be able to quickly sketch any meiotic combination. For example, show the possible gametes for an organism with genotype AaBbCc if “A” and “B” are linked. The answer would be ABC, ABc, abC, abc. You should be able to sketch how this happens. You should be able to identify in this sketch the principle of segregation, the principle of independent assortment, dependent assortment, and independent orientation. This ignores crossing over and mutation of course. 20. Compare genotype to phenotype. Show should be able to do simple Punnett squares that show potential fertilization events. 21. What is meant by heterozygous, homozygous dominant, and homozygous recessive? 22. Mendel’s monohybrid cross experiment resulted in a phenotypic ratio of 3:1 and a genotypic ratio of 1:2:1. Why are these two ratios different? How are they related to each other? 23. Mendel determined that pairs of alleles separate independent of each other. What is this principle called? Describe the experiment that led him to this conclusion. What was the phenotypic ratio? 24. Based on what we know today, why does Mendel’s principle of independent assortment not hold for all pairs of alleles? 25. Compare the P generation, F1 generation and F2 generation. 26. Why is it important for populations of organisms to be diverse? 27. How do asexually reproducing organisms maintain diversity? Why does this work for them but not for sexually reproducing organisms? 28. Make sure you know all the bold words in the chapter. 29. Draw a pair of homologous chromosome with three different genes on them. Show how this pair would go through meiosis. 30. Explain what is meant by a dihybrid cross. What did Mendel learn from his classic dihybrid cross? Explain why he saw this… Be able to do this entire cross as well as any other cross I ask using Punnett squares. 30b. Explain when you would expect the classic 9:3:3:1 ratio. 31. Explain how a testcross is done and why one would do this? 32. Explain how the rule of multiplication and addition apply to Mendel’s principles. Be able to determine the probability of any cross regardless of the number of allele pairs being looked at. For example: AaBBCcddEeFF x AABbccDdEEFf what is the probability of getting AABBCcDdEeFF? answer: ½ x ½ x ½ x ½ x ½ x ½ = 1/64 You should understand how to get this using a Punnett square as well. 33. Pedigrees, know how to analyze them and determine unknowns. Use the powerpoint examples for practice. You can also find other practice problems online. http://www.slideshare.net/Savreetsingh/pedigree-basics 34. Compare recessive to dominant inherited disease. Why are dominant diseases less prevalent compared to recessive disease? Explain how dominant lethal diseases are able to persist if by getting only one gene you die. 49. Know how to do every problem on the genetic problem sheet online. The answers are posted as well. 2. Explain how inherited diseases can be detected early (we discussed four major methods in class – know these techniques and their risks). 3. Compare incomplete dominance, codominance and complete dominance. Give example of each. 4. Know ABO blood types, antibodies produced by people with each, who can receive which and why, universal donor, universal acceptor, etc… You should also know what makes antibodies, the structure of antibodies, how antibodies can lead to agglutination of red blood cells, the number of binding sites on antibodies, etc… 5. Sickle cell anemia. Know what causes it. Explain heterozygote advantage. Discuss the connection to Malaria. Explain how it is an example of incomplete dominance as well as pleiotropy. 6. Compare pleitropy to polygenic inheritance. How are these different to what Mendel observed? 7. Read section 9.15 and expect a single question. 8. Describe the chromosomal theory of inheritance. 9. Discuss how the relative distance between linked genes can be determined using recombinant offspring and crossing over and the recombinant frequencies. Make sure you can do the problems in the powerpoint. 10. There will be a question where you determine recombinant frequencies and you need to arrange the genes on a chromosome based on hypothetical data. 11. Compare how sex determination can be different in non-human organisms to humans. Bees and ants, as discussed in class, follow the haplodiploid sex determination system. How does a male, which is haploid, make gametes? 12. Describe what monoecious means (look it up in the book). Give an example. Compare this to dioecious. You must know these terms. 13. Describe what is means to be hermaphroditic. Give an example of such organisms. 14. Describe how sex-linked gene inheritance is different from autosomal gene inheritance. 15. Read section 4.8 and know the sex-linked diseases. I will give a question on the test with one of these diseases and you need to realize that it is sex-linked. 16. Know how to do every problem on the genetic problem sheet online. The answers are posted as well. 17. Explain why the sickle cell allele frequency is higher than one might predict for an allele that causes a disease when homozygous. 18. Explain how natural selection works. 19. Explain how the experiments of Thomas Hunt showed that genes were on chromosomes and not always independent of each as predicted by Mendel. 20. Make sure you can follow the inheritance of genes that are linked as well as unlinked like the ferret/rabbit problem in the powerpoint.