Pre-AP Unit 4 Homework
Chapter 11
1. Explain the difference between cross-pollination and self-pollination in plants.
2. In sheep a white coat is due to a dominant gene (W), black to its recessive allele (w). A white ewe mated to a white ram produces a black lamb. If they produce another offspring, could it be white? List the genotypes of all the animals mentioned in this problem.
3. In humans normal pigmentation is due to a dominant gene (A), albinism to its recessive allele (a). A normal man marries an albino woman. Their first child is an albino. What are the genotypes of these three persons? If there are more children, what would they probably be like?
4. In humans brown eyes (B) are dominant over blue (b). A brown-eyed man marries a blue-eyed woman and they have 8 children, all brown-eyed. What are the genotypes of all the individuals in the family?
5. If a homozygous German shepherd with dark eyes is bred with a heterozygous German shepherd with light eyes, is it possible for them to have puppies with dark eyes? Explain your answer. (Assume eye color is a simple dominant trait).
6. What is the difference between a heterozygous phenotype produced by incomplete dominance and a heterozygous phenotype produced by codominance?
7. Fill in the numbered blanks in this table on your own paper.
8. If a diploid cell containing 28 chromosomes undergoes meiosis, how many chromosomes will each daughter cell have?
Chapter 12
1. A double helix looks like a twisted ladder. Which parts of a ladder are analogous to the hydrogen bonds and sugar-phosphate backbones of DNA?
2. Use Chargaff’s rule to determine the approximate percentage of thymine in a DNA molecule, if 28% of the nucleotides in the molecule contain adenine.
3. How are DNA and RNA similar? How are they different?
4. What amino acid sequence would be produced from the messenger RNA sequence CGCUAUAGC?
5. Suppose the DNA sequence GCTATATCG was changed to GCGATATCG. How would the products of transcription and translation be affected?
6. How are frameshift and substitution mutations similar? How are they different?
7. How does the DNA possessed by the cells of different tissues of an organism differ from the DNA expressed by those cells?
8. Construct a paper DNA model. Follow the procedure (steps 1-8) on page 313 of your textbook.
Chapter 13
1. Explain why offspring of plants exposed to radiation may have characteristics not found in the original population.
2. Sequence the steps of Wilmot’s technique of cloning a sheep in the correct order:
a. embryo is put into uterus of foster mother
b. nucleus of an adult cell from the animal to be cloned is put into the egg cell
c. nucleus of the egg cell is removed
d. cloned offspring is born
e. normal cell division begins
f. egg cell is taken from an adult
Read the following passage and answer the questions on your own paper.
Treating Diabetes
Diabetes was describes as early as 1500 BC in an ancient document called the Egyptian Egers Papyrus. Early Greek physicians gave diabetes its name because of its symptoms. Diabetes means “siphon” or “fountain”. A person with untreated diabetes needs to urinate frequently.
Other symptoms of diabetes include thirst, hunger, weight loss, and blurred vision. Diabetes is a chronic disease, caused by either a lack of the hormone insulin or the body’s inability to use the insulin it produces. Insulin is normally manufactured in a small cluster of cells in the pancreas called the islets of Langerhans.
Before insulin was discovered, the only treatment for diabetes was a very strict diet that was low in calories and carbohydrates. This type of diet lengthened the lives of diabetic patients, but, without insulin, the patients still died within a few years. In 1921, two Canadian researchers discovered insulin. Today, patients taking insulin can live a normal life span. However, insulin does not cure diabetes, it only provides a chemical that the body is missing.
Until 1982, diabetics used insulin derived from the pancreas of pigs or other farm animals. At times this treatment posed problems because some patients were allergic to pig insulin or other animal insulin.
In 1966, human insulin was synthesized both by an American biochemist and by biochemists in the People’s Republic of China. The United States Food and Drug Administration (USFDA) approved synthetic human insulin in 1982. The insulin is artificially produced in transgenic bacteria. Scientists used genetic engineering techniques to produce these bacteria that contain the human gene for insulin.
3. Describe some of the ways diabetes has been treated throughout history.
4. How is insulin for treating diabetes currently produced?
Chapter 14
1. Which kind of a cell determines whether the offspring will be male or female?
2. Under what condition is a single recessive allele expressed in a male?
3. Why are females less likely to show a trait caused by a recessive allele on the X chromosome?
4. If you know that a woman has hemophilia, what can you infer about her parents’ genotypes?
5. A man and a woman, both with normal vision, decide to have children. The woman’s father is colorblind. What are the chances that their daughters and sons will be colorblind? Explain your answer.
6. A couple preparing for marriage both have blood type AB. They ask you what types of blood their children might have. What would you tell them and how would you explain your conclusions?
7. A case was brought before a judge in which a woman of blood type O presented a baby of blood type O which she claimed as her child and brought suit against a man of blood type AB whom she claimed was the father of the child. If you were the judge, what would your decision be? Explain.