AP/IB Biology Study Guide Genetics

Chapter 13

1. Explain why organisms only reproduce their own kind and why offspring more closely resemble their parents than unrelated individuals of the same species
2. Explain what makes heredity possible
3. Distinguish between asexual and sexual reproduction
4. Diagram the human life cycle and indicate where in the human body that mitosis and meiosis occur: which cells are the result of meoisis and mitosis and which cells are haploid and which are diploid
5. Distinguish among the life cycle patterns of animals, plants, and fungi
6. List the phases of meiosis I and meiosis II and describe the events characteristic of each phase
7. Recognize the phases of meiosis from diagrams or micrographs
8. Describe the process of synapsis during prophase I and explain how genetic recombination occurs
9. Describe key differences between mitosis and meiosis and explain how the end result of meiosis differs from that of mitosis
10. Explain how independent assortment, crossing over, and random fertilization contribute to genetic variation in sexually reproducing organisms
11. Explain why inheritable variation was crucial to Darwin's theory of evolution by natural selection
12. List sources of genetic variation

Chapter 14

1. Describe the favored model of heredity in the 19th century prior to Mendel and explain how this model was inconsistent with observations
2. Explain how Mendel's hypothesis of inheritance differed from the blending theory of inheritance
3. list several features of Mendel's methods that contributed to his success
4. List 4 components of Mendel's hypothesis that led him to deduce the Law of Segregation
5. State the Law of Segregation
6. Use a Punnett square to predict the results of a monohybrid cross and state the phenotypic and genotypic ratios of the F 2 generation
7. Distinguish between genotype and phenotype, heterozygous and homozygous, and dominant and recessive
8. Explain how a testcross can be used to determine if a dominant phenotype is homozygous or heterozygous
9. Define random event and explain why it is significant that allele segregation during meiosis and fusion of gametes at fertilization are random events
10. Use the rule of multiplication to calculate the probability that a particular F 2 individual will be homozygous recessive or dominant
11. Given a Mendelian cross, use the rule of addition to calculate the probability that a particular F 2 individual will be heterozygous
12. Describe 2 alternate hypotheses that Mendel considered for how 2 characters might segregate during gamete formation and explain how he tested these hypotheses
13. State the Law of Independent Assortment
14. Use a Punnett square to predict the results of a dihybrid cross and state the phenotypic and genotypic rations of the F 2 generation.
15. Using the laws of probability, predict from a trihybrid cross between 2 individuals that are heterozygous for all 3 traits what expected proportion of the offspring would be
    1. Homozygous for all 3 traits
    2. Heterozygous for all 3 traits
    3. Homozygous recessive for 2 specific traits and heterozygous for the 3rd
16. Give an example of incomplete dominance and explain why it is not evidence for the blending theory of inheritance
17. Explain how the phenotypic expression of the heterozygote is affected by complete dominance, incomplete dominance, and codominance
18. Describe the inheritance of the ABO blood system and explain why the I A and I B alleles are said to be codominant
19. Define and give examples of pleiotropy
20. Explain what is meant by the phrase :one gene is epistatic to another
21. Explain how epistasis affects the phenotypic ration for a dihybrid cross
22. Describe a simple model for polygenic inheritance and explain why most polygenic characters are described in quantitative terms
23. Describe how environmental conditions can influence the phenotypic expression of a character
24. Given a simple family pedigree, deduce the genotypes for some of the family members
25. Describe the inheritance and expression of cystic fibrosis, Tay-Sachs disease, and sickle-cell disease
26. Explain how a lethal recessive gene can be maintained in a population
27. Explain why consanguinity increases the probability of homozygosity in offspring
28. Give an example of a late-acting lethal dominant in humans and explain how it can escape elimination
29. Explain how carrier recognition, fetal testing, and newborn screening can be used in genetic screening and counseling

Chapter 15

1. Explain how the observations of cytologists and geneticists provided the basis for the chromosome theory of inheritance
2. Describe the contributions that Thomas Hunt Morgan, Walter Sutton, and A. H. Sturtevant made to the current understanding of chromosomal inheritance
3. Explain why Drosophila melanogaster is a good experimental organism
4. Define linkage and explain why linkage interferes with independent assortment
5. Distinguish between parental and recombinant phenotypes
6. Explain how crossing over can unlink genes
7. Map a linear sequence of genes on a chromosome using given recombination frequencies from experimental crosses
8. Explain what additional information cytological maps provide over crossover maps
9. Distinguish between heterogametic sex and homogametic sex
10. Describe sex determination in humans
11. Describe the inheritance of a sex-linked gene such as color blindness
12. Explain why a recessive sex-linked gene is always expressed in human males
13. Explain how an organism compensates for the fact that some individuals have a double dosage of sex-linked genes while others have only one
14. Distinguish among nondisjunction, aneuploiody, and polypolidy; explain how these major chromosomal changes occur; and describe the consequences of their occurrence
15. Distinguish between trisomy and triploidy
16. Distinguish among deletions, duplications, translocations, and inversions
17. Describe the effects of alterations in chromosome structure and explain the role of position effects in altering phenotypes
18. Describe the type of chromosomal alterations implicated in the following human disorders: Down syndrome, Klinefelter syndrome, extra Y, triple-X syndrome, Turner syndrome, cri-du-chat syndrome, and chronic myelogenous leukemia
19. Define genome imprinting and provide evidence to support this model
20. Explain ho the complex expression of a human genetic disorder, such as fragile-X syndrome, can be influenced by triplet repeats and genomic imprinting
21. Give some exceptions to the chromosome theory of inheritance and explain why cytoplasmic genes are not inherited in a Mendelian fashion