Name Class Date OBJECTIVES: *What does DNA look like in different cells? * How does DNA help make proteins? * What happens if a gene changes? *What is heredity? *How did Gregor Mendel study heredity? *Explain meiosis Heredity Use the terms from the following list to complete the sentences below. Each term maybe used only once. Some terms may not be used. heredity genotype dominant traits recessive traits probability sex chromosomes phenotype pedigree allele 1. In the second generation, reappear after disappearing in the first generation. 2. The passing of traits from parents to offspring is called . 3. An organism’s appearance is its . 4. An organism’s inherited alleles together form its 5. If each parent has the same recessive trait, the . of the offspring having the trait goes up. 6. To trace a trait through generations of a family, you can use a(n) . UNDERSTANDING KEY IDEAS Write the letter of the correct answer in the space provided. 7. What kind of plant produces offspring with the same traits as the parent? a. self-pollinating b. cross-pollinating c. true-breeding d. nonbreeding 8. What do you call one set of instructions for an inherited trait? a. alleles b. phenotype c. albinism d. genes Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor. Holt Science and Technology 48 Heredity Name Class Date Chapter Test B continued 9. Two forms of a gene, one from each parent, are called a. alleles. b. phenotypes. c. albinism. d. genes. 10. Offspring that are different from both parents are produced by a. asexual reproduction. b. something going wrong. c. sexual reproduction. d. mitosis. 11. What are chromosomes that carry the same sets of genes? a. twin chromosomes b. homologous chromosomes c. ordinary chromosomes d. asexual chromosomes 12. In humans, what are the sex chromosomes of females? 13. In humans, what are the sex chromosomes of males? 14. What is incomplete dominance? CRITICAL THINKING 15. Peas can both cross-pollinate and self-pollinate. Why was this a key factor in Mendel’s work? Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor. Holt Science and Technology 49 Heredity Name Class Date Chapter Test B continued 16. How is a new cell at the end of meiosis different from the parent cell at the start of meiosis? 17. Explain how a chromatid in the first step of meiosis is different from a chromatid in the seventh step of meiosis. 18. How can a mutation in a DNA base sequence cause a change in a gene and a trait? What determines whether the mutation is passed on to offspring? 19. Give two ways that genetic fingerprinting can be used. 20. Does meiosis happen in all cells? Explain your answer. Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor. Holt Science and Technology 50 Heredity Name Class Date Chapter Test B continued INTERPRETING GRAPHICS Use the Punnett square below to answer questions 18–20. Write the letter of the correct answer in the space provided. 21. In which box is Pp? 22. In which box is PP? 23. In which box is pp? Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor. Holt Science and Technology 51 Heredity