This document provides an overview of genetics concepts including: 1) Traits are physical characteristics studied in genetics, while heredity is the passing of traits from parents to offspring. 2) Genes control traits and come in different forms called alleles which are received from each parent and determine trait inheritance. 3) Dominant alleles will always show in an organism while recessive alleles are hidden by dominant alleles. 4) Genotype refers to an organism's genetic makeup of alleles, while phenotype describes visible traits.

1. Genetics Review

2. Vocabulary Review trait -A physical characteristic. heredity -The passing of traits from parents to offspring. genetics - The scientific study of heredity. 01/21/12 Free template from www.brainybetty.com

3. Question Which of the following is an example of a trait? Bb Talking loud Brown eyes Bleach blonde hair 01/21/12 Free template from www.brainybetty.com

4. Alleles Genes are the factors that control Traits. Alleles are the different forms of Genes . Individual Alleles control the inheritance of Traits. An offspring receives one allele from each parent. 01/21/12 Free template from www.brainybetty.com

5. Question What is the term for factors that control traits? Genes Purebreds Recessives Parents 01/21/12 Free template from www.brainybetty.com

6. Question Which term refers to physical characteristics that are studied in genetics? Traits Offspring Generations Hybrids 01/21/12 Free template from www.brainybetty.com

7. DOMINANT and recessive Alleles A dominant allele is one whose trait always shows up in an organism when the allele is present. - capital letter (AA, Aa) A recessive allele is covered up when the dominant allele is present. - lower case letter (aa) 01/21/12 Free template from www.brainybetty.com

8. Practice R is the dominant allele for a one eyed monster. r is the recessive allele for a monster with two eyes. 01/21/12 Free template from www.brainybetty.com

9. Monster Genetics Rr How many eyes will our monster have????? 01/21/12 Free template from www.brainybetty.com

10. Monster Genetics RR How many eyes will our monster have?? 01/21/12 Free template from www.brainybetty.com

11. Monster Genetics rr How many eyes will our monster have?? 01/21/12 Free template from www.brainybetty.com

12. Question What does the notation TT mean to geneticists? Two dominant alleles Two recessive alleles No dominant alleles One dominant and on recessive allele 01/21/12 Free template from www.brainybetty.com

13. Codominance Some alleles are neither dominant or recessive. Codominance is when alleles are neither dominant or recessive , both alleles are expressed in the offspring. 01/21/12 Free template from www.brainybetty.com

14. What will Happen? You have two flowers, a white and a red, that are crossed. The flowers are codominant. What color will their offspring be. 01/21/12 Free template from www.brainybetty.com

15. Phenotype Phenotype is an organisms physical appearance or its visible traits. Example: a pea plant stem height can be short or tall . 01/21/12 Free template from www.brainybetty.com

16. Genotype Genotype is an organisms genetic makeup, or allele combination. Example: TT, Tt, tt 01/21/12 Free template from www.brainybetty.com

17. Describing genotypes Homozygous (or Purebred) is used to describe an organism that has two identical alleles for a trait. Example: TT and tt Heterozygous (or Hybrid) is used to describe an organism with two different alleles. -Example: Tt 01/21/12 Free template from www.brainybetty.com

18. Question Pick the answer that best describes “Aa”. Homozygous heterozygous 01/21/12 Free template from www.brainybetty.com

19. Punnett Squares A punnett square is a chart that shows all possible combinations of alleles that can result from a genetic cross. 01/21/12 Free template from www.brainybetty.com

20. Punnett Example Yellow is dominant over Green. What is the probability that the offspring will be yellow? 100% 01/21/12 Free template from www.brainybetty.com

21. Punnett Problems In purple people eaters, one-horn is dominant and no horns is recessive. Draw a Punnet Square showing the cross of a purple people eater that is hybrid for horns, with a purple people eater that does not have horns. 01/21/12 Free template from www.brainybetty.com

22. Answer Hybrids have two different alleles for one trait. Hh is the hybrid in the example. No horns would have to be hh because it is a recessive allele. 01/21/12 Free template from www.brainybetty.com

23. Punnett Problems In Bears the dominant allele for brown fur is R, black fur is recessive. The female bear is Rr and the male bear is rr. 01/21/12 Free template from www.brainybetty.com

24. Question What are the four possible phenotypes for the cubs? A. RR, Rr B. Rr, rr C. 2 brown, 2 black D. 3 brown, 1 black 01/21/12 Free template from www.brainybetty.com

25. Question What is the probability that the cub will have black fur? A. 50% B. 25% C. 75% D. 100% 01/21/12 Free template from www.brainybetty.com

26. Question What do you call one set of instructions for an inherited trait? a. alleles b. phenotype c. albinism d. genes 01/21/12 Free template from www.brainybetty.com

27. Question Two forms of a gene, one from each parent, are called a. alleles. b. phenotypes. c. albinism. d. genes. 01/21/12 Free template from www.brainybetty.com

28. Question What is a plant that has two dominant genes or two recessive genes called? a. organism b. genotype c. homozygous d. heterozygous 01/21/12 Free template from www.brainybetty.com

29. Question The allele for freckles, F , is dominant among humans. If a woman with freckles (FF) and a man without freckles (ff) have children, what are the possible genotypes of the children? A. Ff B. FF, Ff, ff C. Ff, ff D. ff 01/21/12 Free template from www.brainybetty.com

30. Question Part of a mouse’s tail is cut off as the mouse escapes from a cat. The mouse later reproduces. Which explanation best describes why the mouse’s offspring have long tails? A. Long tails are a dominant trait. B. Short tails do not appear in the first generation or the second generation. C. Cutting the tail of the mouse changed its genes. D. Cutting the tail of the mouse did not change its genes. 01/21/12 Free template from www.brainybetty.com

31. Question 01/21/12 Free template from www.brainybetty.com What is the genotype of the offspring represented in the upper left-hand box of the Punnett square? A RR B Rr C rr D rrr

32. Question 01/21/12 Free template from www.brainybetty.com What is the genotype of the offspring represented in the upper left-hand box of the Punnett square? A RR B Rr C rr D rrr

33. Question 01/21/12 Free template from www.brainybetty.com What is the ratio of Rr (purple-flowered plants) to rr (white-flowered plants) in the offspring? A 1:3 B 2:2 C 3:1 D 4:0

34. Question Green seed color (G) is dominant to yellow seed color (g). If two heterozygous parents are crossed, what will be the resulting genotypes of the offspring? GG, Gg, gg Gg, gg GG, Gg gg, GG 01/21/12 Free template from www.brainybetty.com