Study Guide - Answers

 Name: ________________________ Date: _________  Biology Unit 8 Study Guide: Genetics 8-1 1. What What is here heredi dity ty?? The passing of traits from parents to offspring 2. Who Who was was Greg Gregor or Mend Mendel el?? The first to develop rules to accurately predict patterns of heredity 3. What organi organism sm did did Mendel Mendel use to perform perform his experim experiments? ents? The pea plant 4. True/Fal True/False: se: Mendel Mendel actually repeated repeated the experiments experiments of another another scientist, scientist, T. T. A. Knight. Knight. True 5. List the three three reasons reasons that that Mendel Mendel chose chose the pea pea plant. plant. The pea plant has many man y traits that have two forms that are easy to tell apart Mating of the plants can be controlled Peas are small, they grow easily, easily, mature quickly, and produce many offspring 6. A cross with one one pair of contrasting contrasting traits traits is known known as a Monohybrid cross 7. In the first first step of his experimen experimentt Mendel allowed allowed the plants plants to ________-____ ________-____________ ____________. ____. This This was important because it produced __________ __________________ plants. This generation is known as the ___ generation. Self-pollinate, true breeding, P 8. In the second step step of his experiment experiment,, Mendel _________-_ _________-________ ______________. _______. The offspri offspring ng of the P generation are known as the ___ generation. Cross-pollinated, F1 9. In the third third step step of the the experiment experiment Mendel allowed allowed the plants plants to to ______________________ ___________________. These offspring are called the ____ generation. Cross-pollinate, F2 10. What is a ratio? ratio? How do you find a ratio? ratio? A comparison of two numbers that have the same unit. To find a ratio divide both numbers by the smaller  number. 11. What was the ratio of the dominant phenotype to recessive phenotype phenotype that Mendel observed? 3 to 1 8-2 12. Finish the following statement statement from your notes: For each inherited trait… An individual has two copies of the gene, one from each parent. 13. What is is an allele allele?? Alternate versions of genes

 Name: ________________________ Date: _________  14. What is a dominant allele? allele? What is a recessive recessive allele? A dominant allele is the allele that is completely expressed. A recessive allele is not expressed when a dominant allele is present. 15. What is homozygous? What is homozygous dominant? Homozygous recessive? recessive? When the two alleles of a gene gen e are the same in an individual. AA aa 16. What is heterozy heterozygous? gous? When two alleles of a gene are different. Aa 17. What is genoty genotype? pe? The set of alleles of an individual. 18. What is is phenotype phenotype?? The physical appearance expressed by b y the alleles. 19. What is the Law of Segrega Segregation? tion? Two alleles of a trait separate when gametes are formed. 20. What is the Law of Independent Assortment? Alleles of different genes separate independently of one another du ring gamete formation. 8-3 and 8-4 21. What is a Punnett Punnett Square Square?? A diagram that predicts all the possible gamete combinations in a cross 22. If the phenotype is dominant but the genotype is unknown what type type of cross would you you perform? Testcross 23. What is probability? probability? The likelihood that a specific event will occur. 24. What is a polygen polygenic ic trait? trait? When several genes influence a trait 25. What is incomplet incompletee dominance? dominance? If intermediate traits between the two parents are expressed, 26. What is is codominance codominance?? When both traits are displayed. 27. When does does a gene gene have multiple multiple alleles alleles?? Genes with three or more alleles? 28. In cats, long hair is recessive to short hair. hair. A true-breeding (homozygous) short-haired male is mated to a long-haired female. What will their kittens look like? All Ll; all short haired 29. Mrs. And Mr. Mr. Jones both have widow’s peaks (dominant). Their first child also has a widow’s peak,  but their second child doesn’t. Mr. Jones accuses Mrs. Jones of being unfaithful to him. Is he

 Name: ________________________ Date: _________  necessarily justified? Why or why not?  No they could both be Ww 30. Mate a rooster that is is homozygous for curly feathers with a hen that is heterozygous heterozygous for straight   feathers. Straight feathers are dominant to curly feathers. a. Choose one letter to represent the allele for curly feathers _______ and straight feathers __________.  b. Write Write out the genotypes of each ea ch parent below:  ______________ X _______________  c. List the gametes for each parent: _____ _____ and ____ ____  Show all work for full credit. d. What are the chances of the offspring having curly feathers? ___________. e. What are the chances of the offspring having straight feathers? _________. a. b. c. d. e.

S, s ss x Ss ss,Ss 1/2 1/2

Patterns of Heredity (8-4 cont) 31. What is is a pedigree pedigree?? A family history that shows how a trait is inherited over several generations. g enerations. 32. What are are carriers carriers?? Heterozygous individuals that don’t show symptoms of the disorder they are carrying 33. What are autosomal autosomal traits traits?? Traits that are found on the autosomes (body chromosomes found in males and females) 34. What are sex-linked sex-linked traits? traits? Traits that appear only on the X-chromosome 35. Why are males more likely to display a sex-linked trait? Because they only have one X chromosome. 36. What is the cause of genetic genetic disorders? disorders? Mutations

Questions 38. and 39. Refer to the following diagram.

 Name: ________________________ Date: _________ 

37. Does Norma have a recessive recessive allele? allele? a. Yes b. No c. Ther Theree is is no no way way to to tel tell. l. 38. How many females females express the the trait? a. 0 b. 2 c. 4 d. 7 39. How many males express express the trait? trait? a. 0 b. 2 c. 4 d. 7