EXAM 3 Study Guide Chapter 9 Study Questions: Patterns of Inheritance Characteristics show various methods of inheritance. Chapter 9 Vocabulary you should be able to define when discussing the important ideas of this section Gene locus Recessive Heterozygous F1 generation Genotypic Ratio Allele Dominant Homozygous F2 generation Phenotypic ratio Genotype True-breeding M ono hybrid cross Testcross Rule of multiplication Phenotype Hybrid P generation Dihybrid cross Pedigree 1. Why was Mendel successful in explaining inheritance when people prior to him had failed? 2. What were five hypotheses about inheritance formed by Mendel and supported by his breeding experiments? His hypotheses, framed in modern day terms, should include how he demonstrated: a. Gene variation b. Diploid set of chromosomes c. Heterozygous determination of dominant and recessive alleles d. The law of segregation e. The law of independent assortment 3. How are the laws of segregation and independent assortment explained by chromosomal events during specific stages of meiosis? (Refer to Fig. 9.16 p.171) 4. Are all characteristics inherited the way Mendel described them? Cite exceptions or extensions to Mendel’s principles by explaining and illustrating the following concepts: a. Incomplete Dominance b. Multiple Alleles c. Co-dominance d. Pleiotropy e. Polygenic Inheritance f. Linkage of genes on same chromosome g. Sex linked genes h. Non-genetic (e.g., environmental) influence New Technologies can provide insight into one’s genetic legacy Chapter 9 module 9.10 5. What procedures are available to prospective parents to determine the “genetic health” of their baby? APPLYING YOUR KNOWLEDGE 1. What are the advantages and disadvantages of sexual and asexual reproduction? 2. Draw a chromosome as it appears in G2 of the cell cycle. Label the sister chromatids, centromere and the kinetochores. 3. Draw a cell with six chromosomes undergoing mitosis. Show the number and appearance of chromosomes at each stage. 4. During pregnancy in humans, an error in mitosis can occur where a particular chromosome does not split. If this error occurs once in development, a baby may be born containing a “mosaic” of cells that do NOT have the same number of chromosomes. a) What stage of mitosis does this occur? b) How many chromosomes could a cell in this baby contain? (HINT: There are 3 possibilities. What are the 3 chromosome totals? EXPLAIN) 5. Draw a cell with three pairs of chromosomes undergoing meiosis. Show the number and appearance of chromosomes at each stage (particularly at the end of Meiosis I and at the end of Meiosis II). 6. a) In terms of chromosome numbers, which division in meiosis (I or II) would be considered a form of “reduction division”? EXPLAIN b) Which division in meiosis (I or II) resembles mitosis? EXPLAIN 7. Solve problems that follow Mendel’s observed modes of inheritance. See below for two examples. Example 1: There is a gene in summer squash plants that determines fruit color. The dominant allele (Y) produces yellow fruit and the recessive allele (y) results in green fruit a. A YY plant will produce what kind of fruit? b. What is the genotype of a plant that produces green fruit? c. When a plant that produces yellow fruit is crossed with a plant that produces green fruit, some of the offspring produce green fruit. What is the genotype of the plant that produces yellow fruit? d. How can you determine the genotype of a plant that produces yellow fruit? Example 2 : Genes “A” and “B” assort independently and affect different traits. What is the probability that two individuals heterozygous for both genes will have an offspring heterozygous for both genes? . 8. Does the principle of segregation always hold true? Give an example in humans to explain your answer. 9. Under what circumstances does the theory of independent assortment not hold true? Describe why. 10.Inspect new situations that illustrate exceptions to Mendel’s observed modes of inheritance. See below for 5 examples. Example 1: Palomino is a color of horse intermediate between chestnut and cream. A horse breeder crossed many of palomino colored horses. The result of the crosses showed a ratio of 1 cream colored, to 2 palomino colored to 1 chestnut colored colt. a. Based on the results of this cross is coat color in the horses described above inherited the way Mendel explained? Why or why not? b. What color of horses would you cross to get all palomino colored colts? Example 2. Gene “A” and gene “B” are found on the same chromosome. In one individual, alleles A and b are on one homologue and alleles a and B on the other. a. What gametes can this organism produce if crossing over does not occur? b. What gametes can this organism produce if crossing over does occur? c. Assume crossing over does not occur. What genotypes may be seen in the offspring of Aabb crossed with AaBb? Example 3. A gene coding for red hair also makes redheaded people resistant to anesthesia. What mode of inheritance does this illustrate? Example 4. How does examination of a particular heterozygous genotype demonstrate co-dominance in human blood typing? Example 5. In the example below, determine the possible modes of inheritance from the following: autosomal recessive atutosomal dominant X-linked recessive X-linked dominant, Y-Linked. Chapter 10, 11 & 12 Study Questions: How is DNA Copied, Expressed, and Manipulated? DNA is the genetic material Chapter 10 Module 10.1 1. How did researchers determine that DNA is the genetic material of the cell? 2. What experiments were conducted to indicate that DNA is the genetic material? DNA and RNA are polymers of nucleotides (Chapter 10 Module 10.2 -10.3) 3. What is the structure of DNA and how was it discovered? 4. Compare and contrast DNA and RNA in terms of nucleotides present and structure. Vocabulary you should be able to define when discussing the important ideas of this section X-ray crystallography Nucleotide Phosphate group Deoxyribose Purines Pyrimidines Adenine Guanine Cytosine Thymine Uracil The structure of the DNA molecule is related to how it replicates. 5. How is a DNA molecule “semi-conserved” following replication? Vocabulary you should be able to define when discussing the important ideas of this section DNA replication DNA polymerases DNA ligase Gene When the genetic blueprint is “read”, certain segments of DNA are transcribed into RNA molecules, some of which are translated into proteins. (Chapter 10 Module 10.6 – 10.15) 6. What must happen for a gene encoded on DNA to be converted into protein? 7. What is the “genetic code”, and why is it considered nearly universal and redundant? 8. Given a DNA sequence, determine the expressed RNA and protein sequences. 9. Describe the transcription initiation, elongation and termination steps. Vocabulary you should be able to define when discussing the important ideas of this section Transcription Promoter RNA Terminator mRNA sequence Polymerase sequence rRNA Translation Ribosomal Initiator tRNA tRNA binding subunits & start codon sites (P & A) Stop codon Translocation tRNA Codon/Anticodon recognition In eukaryotes, RNA is further processed. (Chapter 10 Module 10.10) 10. Why is the mRNA transcript capped? How is this done? 11. Why is the mRNA transcript polyadenylated? How is this done? 12. What is RNA splicing? What is its value? Vocabulary you should be able to define when discussing the important ideas of this section RNA transcript cap Poly A tail Introns Exons The process of Translation: conversion from mRNA to protein. (Chapter 10 Module 10.11-10.15) 13. What is unique about the composition of the ribosome? How is this useful in it’s specificity and fidelity 14. Describe what happens in the A and P site of the ribosome. Mutations can affect the expression of genes (Chapter 10 Module 10.16) 15. Distinguish between chromosomal and single nucleotide mutations. 16. How can uncorrected mutations have negative, neutral, or positive consequences? 17. What is likely to cause the greatest change in gene expression- a base substitution or a base deletion? (Chapter 10 Module 10.20-10.21) 18. What kind of genetic material does a virus contain? 19. How does a virus take advantage of a host cell? 20. What are prions? Chapter 11: Gene expression 21. 22. 23. 24. 25. 26. How is transcription regulated? What are the differences between different types of cells? What is the same? Are both X chromosomes active in females? Does most of the genome code for protein? What other ways is gene expression regulated? What are stem cells? Analysis of DNA and its expression lead to applications that have potential societal benefits and ethical considerations.(Chapter 12) 27. What are the purpose/values and procedural steps of the following techniques? a. gene cloning in recombinant plasmids b. DNA microarrays c. forensic DNA fingerprinting d. gene therapy e. polymerase chain reaction (PCR) Vocabulary you should be able to define when discussing the important ideas of this section Biotechnology Recombinant DNA & Restriction enzyme Transformation gene cloning Reverse transcriptase Nucleic acid probe Gel electrophoresis Restriction fragment length polymorphisms Genetically Modified Organisms 28. 29. 30. 31. How is DNA technology changing the pharmaceutical industry, medicine, and agriculture? What is the difference between genomics and protemics? What was the Human Genome Project? What was the biggest surprise from this project? What are some possible ethical concerns associated with new applications developed by molecular biologists? APPLYING YOUR KNOWLEDGE 1. In 1949, the Austrian scientist Erwin Chargaff observed that whatever DNA he examined, there existed a particular ratio between the amount of adenine and thymine. He found a “curiously” similar ratio between the amount of guanine and cytosine. What was that ratio? (EXPLAIN) 2. It takes energy to break chemical bonds. “Thermophiles” are microorganisms that thrive in extremely hot environments like the Yellowstone hot sulfur springs. In order to survive in such extreme environments their DNA needs to be extremely resistant to heat. Would you expect the DNA of thermophiles to have more guanine and cytosine or more adenine or thymine? (EXPLAIN) 3. Human Immunodeficiency Virus (HIV) before it infects human cells contains one type of genetic material. Following cell infection, HIV uses an enzyme “reverse transcriptase” to convert its genetic material into another form, which then is inserted into human chromosomes. a. Identify the original genetic material in HIV. (EXPLAIN) b. Why might drugs that block reverse transcriptase activity be effective agents for the treatment of AIDS? 4. Suppose there is a gene on a bacterial chromosome with the following sequence: TACGGCTGAGAA. a. What will be the sequence of mRNA nucleotides transcribed from this DNA? b. What will be the sequence of amino acids resulting from the translation of this mRNA? c. Propose a single point mutation that will have NO effect on the translated amino acid sequence. (EXPLAIN) d. Propose a single point mutation that will result in one amino acid substitution. e. Propose a single point mutation that will result in more than one amino acid substitution. 5. A person has been killed, and the murder weapon contains blood from the victim. On the floor near the victim there are a few drops of blood that don’t appear to be the victims. The police officers at a crime scene collect blood from all sources. The have two suspects, but are unable to determine who the murderer is. Using DNA evidence explain how you could determine which of the suspects, if any committed the crime.
