Mendel and Heredity Study Guide - Reed Biology

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Mendel and Heredity Study GuideVocabulary: Trait, Genetics, Purebred, Cross, Law of SegregationWhat is genetics?Whose early work is the basis for much of our current understanding of genetics?How did Mendel’s views on inheritance differ from the views of many scientists of his time?In designing his experiments, Mendel made three important choices that helped him see patterns of inheritance. In the table below, list Mendel’s three choices and write an example of how he put each of these choices into action.Mendel’s ChoicesExample4.5.6.7. Why did Mendel use pea plants?8. Fill in the sequence diagram below to summarize Mendel’s experimental process.Bred flowers resulting in F1 generation with dominant phenotype.Resulted in F2 generation with both dominant and recessive phenotypes.9. Mendel concluded that traits are inherited as “discrete units”. What do we call these discrete units today?10. What two conclusions make up Mendel’s law of segregation?11. Segregation means “separation”. What is “segregated” in Mendel’s law of segregation?12. What does “purebred” mean?Traits, Genes, and Alleles Study GuideVocabulary: Gene, Allele, Homozygous, Heterozygous, Genome, Genotype, Phenotype, Dominant, RecessiveWhat is the relationship between a gene and a protein? What is an allele?What term describes a pair of alleles that are the same? That are different?Write a definition of homologous chromosomes using the terms “gene” and “allele”.In the space below, draw a pair of homologous chromosomes. Label the chromosomes with two sets of genes, one with homozygous alleles (Gene A, Gene A) and one with heterozygous alleles (Gene B, Gene b)Write an analogy to show the difference between genotype and phenotype.How are alleles represented on paper?Fill in the table below with the missing genotype, phenotype (dominant or recessive), or alleles (TT, Tt, tt).GenotypePhenotypeAllelesHomozygous dominantRecessiveTtIf an organism has a recessive trait, can you determine its genotype for that trait?What factors besides alleles affect phenotype?What type of alleles are present in an organism with a QQ genotype?What is an alternative form of a gene?What is the opposite of homozygous? Of dominant?Traits and Probability Study GuideVocabulary: Punnett Square, Monohybrid Cross, Testcross, Dihybrid Cross, Law of Independent Assortment, ProbabilityIdentify what of each of the numbered parts represents in the Punnett Square below. Then draw lines from each of the parents’ alleles to the corresponding alleles in the offspring.2. 1. 3. 4. Why does each parent contribute only one alleles to the offspring?5. You know a ratio is a comparison that tells how two or more things relate. What is a genotypic ratio? A phenotypic ratio?6. What is the genotypic ratio of the offspring in the figure above?7. What is the phenotypic ratio of the offspring above?8. What is a dihybrid cross?9. Why does each parent organism in the F1 generation have four alleles in figure 6.17 (Caiman book)?10. Suppose an organism had the genotype AABb. What two types of gametes could result from this allele combination?11. What is the phenotypic ratio that results from a dihybrid cross between two organisms that are heterozygous for BOTH traits? See figure 6.17.12. Probability predicts the number of occurrences, not the number of occurrences.13. To calculate the probability that two independent events will happen together, the probability of each individual event.14. In Figure 6.18, the probability of getting one coin that is heads up and one coin that is tails up is .15. What is a testcross?16. What is independent in the law of independent assortment?Meiosis and Genetic Variation Study GuideVocabulary: Crossing over, Genetic linkageWhat are two ways that sexual reproduction helps create and maintain genetic diversity?Which does sexual reproduction create, new alleles or new combinations of alleles?How is the production of unique genetic combinations an advantage to organisms and species?Are chromosomes in a duplicated or an unduplicated state when crossing over occurs?Use sketches to illustrate how crossing over contributes to genetic diversity. Use Figure 6.20 for reference.Draw a cell with four chromosomes in the first box. Make one pair of chromosomes large and the other pair small. Color in one large chromosome and one small chromosome. Leave the other two chromosomes white.In the next box, draw the cell in prophase I. Have each pair of homologous chromosomes line up together – large with large, small with small.In the third box, show crossing over between each pair of homologous chromosomes.In the last box, show what the chromosomes look like as a result of crossing over. You will use this sketch in the next exercise.Refer to your cell sketch in the last box in the diagram above. Also refer to figure 6.5 if necessary.In the first box below, show what your cell would look like at the end of meiosis I. Remember, the result will be two cells that have one duplicated chromosome from each homologous pair.In the second box, show what your cell would look like at the end of meiosis II. Remember, the result will be four cells that have one (unduplicated) chromosomes from each homologous pair.If genes A and B are located on separate, nonhomologous chromosomes, will they follow Mendel’s law of independent assortment? Explain.If genes A and B are located very close together on the same chromosome, are they likely to follow Mendel’s law of independent assortment? Explain.If genes A and B are located at opposite ends on the same chromosome, are they likely to follow Mendel’s law of independent assortment?The exchange of chromosome segments between homologous chromosomes is called The tendency for two genes that are located close together on a chromosome to be inherited together is called .Vocabulary PracticeSomatic cellgametehomologous chromosomeautosomesex chromosomesexual reproductionfertilizationdiploidHaploidmeiosisgametogenesisspermegg polar bodytraitgeneticsPurebredcrosslaw of segregationgeneallelehomozygousheterozygousgenomeGenotypephenotypedominantrecessivePunnett SquaremonohybridtestcrossdihybridLaw of independent assortmentprobabilitycrossing overgenetic linkageChoose the situation that most closely relates to each vocabulary word.Fertilization: a) union of gametesb) division of chromosomesPurebred: a) a scruffy muttb) a sleek Labrador retrieverDiploid: a) a dollarb) 50 centsSexual Reproduction: a) produces genetically identical offspringb) produces genetically unique offspring.Trait: a) inheriting your father’s laughb) inheriting your father’s watchHomologous chromosomes: a) carry the same genesb) carry identical genesPunnett Square: a) like playing tic-tac-toeb) like playing rock, paper, scissorsGenome: a) like a computer hard driveb) like a computer screenPolar body: a) becomes a babyb) becomes broken down by the bodyMeiosis: a) preserves chromosome numberb) reduces chromosome numberTestcross: a) reveals phenotypeb) reveals genotypeProbability: a) the likelihood a given event will occurb) the number of times a given even has occurredFor each pair of words listed, list one way they are similar and one way they are different.SimilarityWord PairDifference Law of segregationLaw of Independent assortmentAutosomeSex chromosomeSpermEggHomozygousHeterozygousDominantRecessiveDiploidHaploidMonohybrid crossDihybrid crossComplete the story using the following terms: crossed, crossing over, gametogenesis, gene, genetic, genetic linkage, law of independent assortment, law of segregation, purebred, traitsGregor Mendel wanted to understand how were inherited, so he performed experiments using peas plants. Mendel used plants that were , which means that the plants had self-pollinated for so long that the offspring always looked like the parent plant. He examined seven “either-or” characteristics. First, Mendel a plant displaying the dominant phenotype with a plant displaying the recessive phenotype. Next, he allowed the offspring of this cross, the F1 generation, to self-pollinate, and then calculated the phenotypic ratios that he observed in the F2 offspring.From his monohybrid crosses, Mendel developed his first law, the . This law states that each parent organism has two copies of each discrete unit, or , and that the two copies separate from each other during . Mendel then performed dihybrid crosses, and as a result, developed his second law, the . This law states essentially that the inheritance of one trait does NOT influence the inheritance of another trait. Mendel’s second law applies to genes that are on separate chromosomes or to genes that are so far apart on the same chromosome that they have a strong chance of being separated by . However, his second law does NOT apply to genes that exhibit because they are close together on the same chromosome.Chromosomes and Phenotype Study GuideVocabulary: carrier, sex-linked gene, X chromosome inactivationWhat are sex chromosomes?What are autosomes?How is a carrier different from a person who has a genetic disorder?Complete the two Punnett Squares below to compare autosomal recessive disorders with autosomal dominant disorders. Fill in the possible genotypes for offspring, and write in the phenotype (no disorder, disorder, carrier) for each.Autosomal RecessiveAutosomal DominantDdDdDDddWhat are sex-linked genes?Fill in the Punnett square below to show the pattern of inheritance for sex chromosomes.Sex Chromosome InheritanceXXXYIn humans, how does a gamete from a male determine the sex of offspring?For what are genes on the Y chromosome responsible?How are sex-linked genes expressed differently in the phenotypes of males and females?The verb carry means “to transport”. How is the everyday meaning of carry related to the meaning of the term carrier in genetics?What is X chromosome inactivation?Complex Patterns of Inheritance Study GuideVocabulary: Incomplete Dominance, Codominance, Polygenic TraitHow is incomplete dominance different from a dominant and recessive relationship?How is codominance different from dominant and recessive relationship?What is a multiple allele trait?In the table below, desire how phenotypes appear in incomplete dominance and codominance. Then sketch examples of each.InteractionPhenotypeExampleIncomplete Dominance4.5.Codominance6.7.Use the chart below to take notes on polygenic traits and epistasis.Many genes may interact to produce one trait.Polygenic Traits:Epistasis: 8. Why is genotype not the only factor that affects phenotype?9. List and explain two examples of how environment and genotype can interact.10. The prefix in- means “not”. How is the meaning of this prefix related to the meaning of incomplete dominance?11. The prefix co- means “together”. How is the meaning of this prefix related to the meaning of codominance?12. The prefix poly means “many”, and the term genic means “related to genes”. How do these word parts combine to give the meaning of polygenic?Gene Linkage and Mapping Study GuideVocabulary: Linkage mapWhat is gene linkage?Why were fruit flies useful in Morgan’s research?What is the difference between a wild type and a mutant type?What did Morgan conclude from his research on fruit flies?Complete the sequence below to take notes about the discovery of gene linkage.Morgan:Punnett, Bateson:Mendel:Genes assort independently of one another.How is the distance between two genes related to the chance they are inherited together?What hypothesis was the basis of Sturtevant’s research?What is a linkage map?How are cross-over frequencies related to linkage maps?What do linkage maps show about genes on a chromosome?Human Genetics and Pedigree Study GuideVocabulary: Pedigree, Karyotype.How does genetic inheritance follow similar patterns in all sexually reproducing organisms?How are single-gene traits useful in studying human genetics?Who can be carriers of autosomal disorders?Why can females, but NOT males, be carriers of sex-linked genetic disorders?What is a pedigree?How are phenotypes used in pedigree analysis?What information on a pedigree can tell you whether a gene is on an autosome or on a sex chromosome?Complete the chart to follow the logic necessary to fill out a pedigree for a sex-linked gene. Use XD and Xd for the dominant and recessive X-linked genes, respectively.Tracing Sex-Linked GenesPhenotype must haveGenotypeFemale, Recessive phenotypemust haveMale, recessive phenotypemust haveMust haveXDXdParental Phenotypemust have Parental Genotypecould haveOffspring GenotypeFemale carrier, must havecould haveNormal maleFemale carrier,must havecould haveMale w/recessive phenotypeFemale recessive phenotypemust havecould haveNormal maleFemale recessive phenotypemust havecould haveMale recessive phenotypeWhat are two methods that are used to directly study human chromosomes?What does a karyotype show about chromosomes?What is a karyotype?Vocabulary PracticeCarriersex-linked genex chromosome inactivationincomplete dominancecodominancepolygenic traitlinkage mappedigreekaryotypeRead each phrase and write the word that it most closely describes. Then write another phrase that describes the word in a different way.Phrase 1WordPhrase 2Picture of all human chromosomesKaryotypeCan show large changes in chromosomesGenes located on the sex chromosomes.Shows the relative locations of genes on a chromosome.One X chromosome is randomly turned off.A chart that is used to trace phenotypes and genotypes in a family.Many genes interact to produce a single trait.An “in-between” phenotype.Answer the questions to show your understanding of the vocabulary words.Which is like a karyotype, a satellite weather map, or the temperature on one street corner?Is incomplete dominance like a glass of cranberry-raspberry juice or a pizza with everything?Is X chromosome inactivation like an electrical generator or a power failure?Would a pedigree be used to trace genes in a family or to send a dog to obedience school?Is codominance like doing your homework or two people talking at the same time?Which is like a Carrier, a ferry crossing a lake or a door opening?Are exact directions or a general idea of where you are going more like a linkage map?Is a polygenic trait more like a basketball team or a figure skater?Pick the Vocabulary Term that answers the Riddle.I am the process that randomly turns off one X chromosome in a human female’s cells.I am an interaction between two alleles in which both alleles are fully and separately expressed.I am a chart that can be used to trace genes through a family.I am a picture that shows the overall structure of a chromosome.I am an interaction between two alleles that produces a phenotype that is between the phenotypes of homozygotes.I am a person who does not show a genetic disorder, but I can pass it on to my offspring.I am a map of genes on a chromosome, but I do not show the exact locations of the genes.I am a trait that is the result of many genes.Find the Odd Word. Circle the word that does not belong and explain why it does not belong.Karyotypelinkage mapX chromosome inactivationExplanation:Sex-linked genepolygenic traitcarrierExplanation:Linage mapincomplete dominancecodominanceExplanation:Incomplete dominancekaryotypepedigreeExplanation:Read each analogy and determine the word that is most like it.Airport bag handler:Blending the ingredients of a fruit smoothie:Randomly flipping switches in an electrical panel:A still-life painting:All of the people who make up the United States:Mixing the ingredients of a fruit salad:A train schedule that shows the stops made by the train:Write your own analogies to show the meaning of these terms:Sex-linked genes:Pedigree: ................
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