Ecology 21 - BIOLOGY JUNCTION

AP Lecture Guide 14 – Mendel and The Gene Idea

AP Biology: CHAPTER 14

MENDEL AND THE GENE IDEA

1. How does the “blending hypothesis” differ from the “particulate hypothesis” for the

transmission of traits?

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2. List a few of the advantages of Mendel’s choice of the garden pea as a model organism.

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3. Use the diagram to label the generations: P, F1, F2, pure, hybrid, and make notes of Mendel’s observations.

5. Using the diagram in Question 3, describe how the Law of Segregation applies to the F1 and to the F2 generations.

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6. When does the segregation of alleles occur? _____________________________________

7. What is the difference between an allele and a gene?

a. allele __________________________________________________________________

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b. gene __________________________________________________________________

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8. Briefly define the following terms:

a. homozygous ____________________________________________________________

b. heterozygous ___________________________________________________________

c. phenotype ______________________________________________________________

d. genotype _______________________________________________________________

9. What is the purpose of a test cross? ____________________________________________

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10. When two traits are on different (non-homologous) chromosomes, how are they inherited?

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a. Indicate the phenotypic ratios that result in the F2 from the F1 cross (dihybrid cross)

11. Use the rules of probability to determine the expected ratio of offspring showing two recessive traits in the trihybrid cross (PpYyRr X Ppyyrr).

12. Describe and give an example of incomplete dominance. ___________________________

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13. How does codominance compare to incomplete dominance? ________________________

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14. How is blood type an example of multiple alleles? _________________________________

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15. Define and give an example of pleiotropy. _______________________________________

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16. Define and give an example of epistasis. ________________________________________

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17. What is observed when traits are polygenic? _____________________________________

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18. The expression of phenotypes is often a result of both… ____________________________

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19. Briefly describe each of the following genetic disorders:

a. Cystic fibrosis ___________________________________________________________

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b. Tay-Sachs _____________________________________________________________

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c. Sickle cell anemia _______________________________________________________

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d. Achondroplasia __________________________________________________________

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e. Huntington’s disease _____________________________________________________

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20. How can a parent learn the risks of having a child with a genetic disorder?

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AP Lecture Guide 20 – DNA Technology

AP Biology: Chapter 20

DNA TECHNOLOGY

1. Define biotechnology.

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2. What is meant by “recombinant DNA technology?”

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3. List some of the organisms we have been modifying for many hundreds of years.

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4. Why are bacteria ideal workhorses for biotechnology?

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5. What are other organisms used in biotechnology?

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6. How does gene cloning differ from human cloning?

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7. Why is DNA cloning considered an important technology?

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8. What are plasmids?

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9. What is the function of restriction enzymes in bacteria?

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10. How do bacteria protect their DNA from the effects of the restriction enzymes?

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11. How do biologists make use of restriction enzymes?

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12. What is a genomic library?

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13. How is cDNA different from typical eukaryote DNA?

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14. Describe the steps involved in cloning a gene.

15. How can transformed bacteria that carry genes of interest be identified and isolated from the majority of non-transformed bacteria?

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16. What can be accomplished with Nucleic Acid Hybridization?

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17. What is the purpose of the Polymerase Chain Reaction?

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18. List some advantages & uses of the PCR technique.

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19. How are DNA fragments of different sizes separated?

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20. What is a RFLP? How are they made?

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21. What does the technique of Southern Blotting accomplish?

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22. What are some other techniques that build on the Southern Blotting technique?

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23. What was the goal of the Human Genome Project?

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24. List some of the most important things we learned by completing the Human Genome Project.

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25. What is the Sanger Sequencing Method used for?

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26. How does the shot-gun approach differ from the whole-genome sequencing?

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27. In the future, DNA chips may be used for regular diagnostics. What do the florescent spots indicate when the chip is read?

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28. How can DNA technology be used to diagnose a carrier of a genetic disorder?

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29. What is the goal of gene therapy?

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30. How has forensics made use of DNA technology? Give a specific example.

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31. What is currently used by the FBI to do a DNA fingerprint in a criminal investigation?

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32. What technique has been used to modify agricultural plants?

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33. List a few of the traits that have been engineered into agricultural plants? Could any of these

pose an environmental threat?

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AP Lecture Guide 22 – Descent with Modification

AP Biology: CHAPTER 22- DESCENT WITH MODIFICATION

1. Identify the three significant historical themes that set the stage for Darwinian evolutionary

theory.

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2. What were the two major points made in The Origin of Species?

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3. What were the conventional paradigms in the 1800’s when Darwin developed his theories?

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4. What was the contribution of Carolus Linnaeus to the evolutionary theories?

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5. How did the study of fossils help Darwin shape his theories?

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6. How did geological gradualism and uniformitarianism influence Darwin?

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7. Identify the two principles of Lamarck’s theory of evolution.

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8. How did the observations during his voyage on the Beagle influence Darwin’s theories?

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9. Why were the Galápagos Islands so important to Darwin’s observations?

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10. What are the elements for the formation of new species?

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11. What is the driving force behind the evolution of the 14 species of finches on the

Galapagos?

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12. What was Wallace’s role in the Theory of Natural Selection?

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13. What were the main points of The Origin of Species?

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14. Define Descent with Modification.

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15. How does the “tree analogy” represent the evolutionary relationships of creatures?

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16. Summarize the observations and inferences recognized as the backbone of evolution by

natural selection.

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17. Observations:

a. ______________________________________________________________________

b. ______________________________________________________________________

c. ______________________________________________________________________

d. ______________________________________________________________________

e. ______________________________________________________________________

18. Inferences:

a. ______________________________________________________________________

b. ______________________________________________________________________

c. ______________________________________________________________________

19. How did Darwin’s experience with artificial selection influence his theories of evolution?

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20. For each of the following, indicate how it is used as evidence of evolution by natural

selection.

a. Paleontology ____________________________________________________________

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b. Biogeography ___________________________________________________________

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c. Resistance to insecticides _________________________________________________

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d. Drug Resistance _________________________________________________________

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e. Homology ______________________________________________________________

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f. Homologous structures ___________________________________________________

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g. Vestigial organs _________________________________________________________

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h. Embryology ____________________________________________________________

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i. Biochemical similarity _____________________________________________________

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AP Genetics Problems

Genetics Problems

1. A rooster with gray feathers is mated with a hen of the same phenotype. Among their offspring, 15 chicks are gray, 6 are black, and 8 are white.

What is the simplest explanation for the inheritance of these colors in chickens?
What offspring would you predict from the mating of a gray rooster and a black hen?

2. In some plants, a true-breeding, red-flowered strain gives all pink flowers when crossed with a white-flowered strain: RR (red) x rr (white) —> Rr (pink). If flower position (axial or terminal) is inherited as it is in peas what will be the ratios of genotypes and phenotypes of the generation resulting from the following cross: axial-red (true-breeding) x terminal-white? What will be the ratios in the F2 generation?

3. Flower position, stem length, and seed shape were three characters that Mendel studied. Each is controlled by an independently assorting gene and has dominant and recessive expression as follows:

Character	Dominant	Recessive
Flower position	Axial (A )	Terminal (a )
Stem length	Tall (T )	Dwarf (t )
Seed shape	Round (R )	Wrinkled (r)

If a plant that is heterozygous for all three characters were allowed to self-fertilize, what proportion of the offspring would be expected to be as follows: (Note – use the rules of probability (and show your work) instead of huge Punnett squares)

homozygous for the three dominant traits
homozygous for the three recessive traits
heterozygous
homozygous for axial and tall, heterozygous for seed shape

4. A black guinea pig crossed with an albino guinea pig produced 12 black offspring. When the albino was crossed with a second one, 7 blacks and 5 albinos were obtained.

What is the best explanation for this genetic situation?
Write genotypes for the parents, gametes, and offspring.

5. In sesame plants, the one-pod condition (P ) is dominant to the three-pod condition (p ), and normal leaf (L ) is dominant to wrinkled leaf (l) . Pod type and leaf type are inherited independently. Determine the genotypes for the two parents for all possible matings producing the following offspring:

318 one-pod normal, 98 one-pod wrinkled
323 three-pod normal, 106 three-pod wrinkled
401 one-pod normal
150 one-pod normal, 147 one-pod wrinkled, 51 three-pod normal, 48 three-pod wrinkled
223 one-pod normal, 72 one-pod wrinkled, 76 three-pod normal, 27 three-pod wrinkled

6. A man with group A blood marries a woman with group B blood. Their child has group O blood.

What are the genotypes of these individuals?
What other genotypes and in what frequencies, would you expect in offspring from this marriage?

7. Color pattern in a species of duck is determined by one gene with three alleles. Alleles H and I are codominant, and allele i is recessive to both. How many phenotypes are possible in a flock of ducks that contains all the possible combinations of these three alleles?

8. Phenylketonuria (PKU) is an inherited disease caused by a recessive allele. If a woman and her husband are both carriers, what is the probability of each of the following?

all three of their children will be of normal phenotype
one or more of the three children will have the disease
all three children will have the disease
at least one child out of three will be phenotypically normal

(Note: Remember that the probabilities of all possible outcomes always add up to 1)

9. The genotype of F1 individuals in a tetrahybrid cross is AaBbCcDd. Assuming independent assortment of these four genes, what are the probabilities that F2 offspring would have the following genotypes?

aabbccdd
AaBbCcDd
AABBCCDD
AaBBccDd
AaBBCCdd

10. In 1981, a stray black cat with unusual rounded curled-back ears was adopted by a family in California. Hundreds of descendants of the cat have since been born, and cat fanciers hope to develop the “curl” cat into a show breed. Suppose you owned the first curl cat and wanted to develop a true breeding variety.

How would you determine whether the curl allele is dominant or recessive?
How would you select for true-breeding cats?
How would you know they are true-breeding?

11. What is the probability that each of the following pairs of parents will produce the indicated offspring (assume independent assortment of all gene pairs?

AABbCc x aabbcc —-> AaBbCc
AABbCc x AaBbCc —–> AAbbCC
AaBbCc x AaBbCc —–> AaBbCc
aaBbCC x AABbcc —-> AaBbCc

12. Karen and Steve each have a sibling with sickle-cell disease. Neither Karen, Steve, nor any of their parents has the disease, and none of them has been tested to reveal sickle-cell trait. Based on this incomplete information, calculate the probability that if this couple should have another child, the child will have sickle-cell anemia.

13. Imagine that a newly discovered, recessively inherited disease is expressed only in individuals with type O blood, although the disease and blood group are independently inherited. A normal man with type A blood and a normal woman with type B blood have already had one child with the disease. The woman is now pregnant for a second time. What is the probability that the second child will also have the disease? Assume both parents are heterozygous for the “disease” gene.

14. In tigers, a recessive allele causes an absence of fur pigmentation (a “white tiger”) and a cross-eyed condition. If two phenotypically normal tigers that are heterozygous at this locus are mated, what percentage of their offspring will be cross-eyed? What percentage will be white?

15. In corn plants, a dominant allele I inhibits kernel color, while the recessive allele i permits color when homozygous. At a different locus, the dominant gene P causes purple kernel color, while the homozygous recessive genotype pp causes red kernels. If plants heterozygous at both loci are crossed, what will be the phenotypic ratio of the F1 generation?

16. The pedigree below traces the inheritance of alkaptonuria, a biochemical disorder. Affected individuals, indicated here by the filled-in circles and squares, are unable to break down a substance called alkapton, which colors the urine and stains body tissues. Does alkaptonuria appear to be caused by a dominant or recessive allele? Fill in the genotypes of the individuals whose genotypes you know. What genotypes are possible for each of the other individuals?

17. A man has six fingers on each hand and six toes on each foot. His wife and their daughter have the normal number of digits (5). Extra digits is a dominant trait. What fraction of this couple’s children would be expected to have extra digits?

18. Imagine you are a genetic counselor, and a couple planning to start a family came to you for information. Charles was married once before, and he and his first wife had a child who has cystic fibrosis. The brother of his current wife Elaine died of cystic fibrosis. What is the probability that Charles and Elaine will have a baby with cystic fibrosis? (Neither Charles nor Elaine has the disease)

19. In mice, black color (B ) is dominant to white (b ). At a different locus, a dominant allele (A ) produces a band of yellow just below the tip of each hair in mice with black fur. This gives a frosted appearance known as agouti. Expression of the recessive allele (a ) results in a solid coat color. If mice that are heterozygous at both loci are crossed, what will be the expected phenotypic ratio of their offspring?

20. The pedigree below traces the inheritance of a vary rare biochemical disorder in humans. Affected individuals are indicated by filled-in circles and squares. Is the allele for this disorder dominant or recessive? What genotypes are possible for the individuals marked 1, 2, and 3.

Solutions

Genetic Problems Solutions Campbell Ch14

Genetics Problems Campbell 1. A man with hemophilia (a recessive , sex-linked condition has a daughter of normal phenotype. She marries a man who is normal for the trait. What is the probability that a daughter of this mating will be a hemophiliac? A son? If the couple has four sons, what is the probability that all four will be born with hemophilia?

Solution

2. Pseudohypertropic muscular dystrophy is a disorder that causes gradual deterioration of the muscles. It is seen only in boys born to apparently normal parents and usually results in death in the early teens. (a) Is pseudohypertrophic muscular dystrophy caused by a dominant or recessive allele? (b) Is its inheritance sex-linked or autosomal? (c) How do you know? Explain why this disorder is always seen in boys and never girls.

Solution

3. Red-green color blindness is caused by a sex-linked recessive allele. A color-blind man marries a woman with normal vision whose father was color-blind. (a) What is the probability that they will have a color-blind daughter? (b) What is the probability that their first son will be color-blind? (Note: the two questions are worded a bit differently.)

Solution

4. A wild-type fruit fly (heterozygous for gray body color and normal wings was mated with a black fly with vestigial wings. The offspring had the following phenotypic distribution: wild type, 778; black-vestigial, 785; black-normal, 158; gray-vestigial, 162. What is the recombination frequency between these genes for body color and wing type.

Solution

5. In another cross, a wild-type fruit fly (heterozygous for gray body color and red eyes) was mated with a black fruit fly with purple eyes. The offspring were as follows: wild-type, 721; black-purple, 751; gray-purple, 49; black-red, 45. (a) What is the recombination frequency between these genes for body color and eye color? (b) Following up on this problem and problem 4, what fruit flies (genotypes and phenotypes) would you mate to determine the sequence of the body color, wing shape, and eye color genes on the chromosomes?

Solution

6. A space probe discovers a planet inhabited by creatures who reproduce with the same hereditary patterns as those in humans. Three phenotypic characters are height (T = tall, t = dwarf), hearing appendages (A = antennae, a = no antennae), and nose morphology (S = upturned snout, s = downturned snout). Since the creatures were not “intelligent” Earth scientists were able to do some controlled breeding experiments, using various heterozygotes in testcrosses. For a tall heterozygote with antennae, the offspring were tall-antennae, 46; dwarf-antennae 7; dwarf-no antennae 42; tall-no antennae 5. For a heterozygote with antennae and an upturned snout, the offspring were antennae-upturned snout 47; antennae-downturned snout, 2; no antennae-downturned snout, 48: no antennae-upturned snout 3. Calculate the recombination frequencies for both experiments.

Solution

7. Using the information from problem 6, a further testcross was done using a heterozygote for height and nose morphology. The offspring were tall-upturned nose, 40; dwarf-upturned nose, 9; dwarf-downturned nose, 42; tall-downturned nose, 9. Calculate the recombination frequency from these data; then use your answer from problem 6 to determine the correct sequence of the three linked genes.

Solution

8. Imagine that a geneticist has identified two disorders that appear to be caused by the same chromosomal defect and are affected by genomic imprinting: blindness and numbness of the limbs. A blind woman (whose mother suffered from numbness) has four children, two of whom, a son and daughter, have inherited the chromosomal defect. If this defect works like Prader-Willi and Angelman syndromes, what disorders do this son and daughter display? What disorders would be seen in their sons and daughters?

Solution

9. What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?

Solution

10. An aneuploid person is obviously female, but her cells have two Barr bodies. what is the probable complement of sex chromosomes in this individual?

Solution

11. Determine the sequence of genes along a chromosome based on the following recombination frequencies: A-B, 8 map units; A-C, 28 map units; A-D, 25 map units; B-C , 20 map units; B-D, 33 map units.

Solution

12. About 5% of individuals with Downs syndrome are the result of chromosomal translocation. In most of these cases, one copy of chromosome 21 becomes attached to chromosome 14. How does this translocation lead to children with Down syndrome?

Solution

13. Assume genes A and B are linked and are 50 map units apart. An individual heterozygous at both loci is crossed with an individual who is homozygous recessive at both loci. (a) What percentage of the offspring will show phenotypes resulting from crossovers? (b) If you did not know genes A and B were linked, how would you interpret the results of this cross?

Solution

14. In Drosophila, the gene for white eyes and the gene that produces “hairy” wings have both been mapped to the same chromosome and have a crossover frequency of 1.5%. A geneticist doing some crosses involving these two mutant characteristics noticed that in a particular stock of flies, these two genes assorted independently; that is they behaved as though they were on different chromosomes. What explanation can you offer for this observation?

Solution

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