Genetics Review Biology Class Vocabulary Review trait A

Genetics Review Biology Class

Vocabulary Review • trait -A physical characteristic. • heredity -The passing of traits from parents to offspring. • genetics - The scientific study of heredity. 12/2/2020 2

Question Which of the following is an example of a trait? A. Bb B. Talking loud C. Brown eyes D. Bleach blonde hair 12/2/2020 3

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. 12/2/2020 4

Question What is the term for factors that control traits? A. Genes B. Purebreds C. Recessives D. Parents 12/2/2020 5

Question Which term refers to physical characteristics that are studied in genetics? A. Traits B. Offspring C. Generations D. Hybrids 12/2/2020 6

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) 12/2/2020 Free template from www. brainybetty. com 7

Practice • R is the dominant allele for a one eyed monster. • r is the recessive allele for a monster with two eyes. 12/2/2020 8

Monster Genetics • Rr • How many eyes will our monster have? ? ? 12/2/2020 9

Monster Genetics • RR • How many eyes will our monster have? ? 12/2/2020 Free template from www. brainybetty. com 10

Monster Genetics • rr • How many eyes will our monster have? ? 12/2/2020 Free template from www. brainybetty. com 11

Question What does the notation TT mean to geneticists? A. Two dominant alleles B. Two recessive alleles C. No dominant alleles D. One dominant and on recessive allele 12/2/2020 12

Codominance • Some alleles are neither dominant or recessive. • Codominance is when alleles are neither dominant or recessive, both alleles are expressed in the offspring. 12/2/2020 13

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. 12/2/2020 14

Phenotype • Phenotype is an organisms physical appearance or its visible traits. • Example: a pea plant stem height can be short or tall. 12/2/2020 15

Genotype • Genotype is an organisms genetic makeup, or allele combination. • Example: TT, Tt, tt 12/2/2020 Free template from www. brainybetty. com 16

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 12/2/2020 Free template from www. brainybetty. com 17

Question Pick the answer that best describes “Aa”. A. Homozygous B. heterozygous 12/2/2020 18

Punnett Squares • A punnett square is a chart that shows all possible combinations of alleles that can result from a genetic cross. 12/2/2020 19

Punnett Example • Yellow is dominant over Green. • What is the probability that the offspring will be yellow? 100% 12/2/2020 20

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. 12/2/2020 21

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. 12/2/2020 22

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. 12/2/2020 Free template from www. brainybetty. com 23

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 12/2/2020 24

Question • What is the probability that the cub will have black fur? A. 50% B. 25% C. 75% D. 100% 12/2/2020 25

Question What do you call one set of instructions for an inherited trait? a. alleles b. phenotype c. albinism d. genes 12/2/2020 26

Question Two forms of a gene, one from each parent, are called a. alleles. b. phenotypes. c. albinism. d. genes. 12/2/2020 27

Question What is a plant that has two dominant genes or two recessive genes called? a. organism b. genotype c. homozygous d. heterozygous 12/2/2020 Free template from www. brainybetty. com 28

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 12/2/2020 29

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. 12/2/2020 30

Question 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 12/2/2020 31

Question 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 12/2/2020 32

Question 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 12/2/2020 33

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? A. GG, Gg, gg B. Gg, gg C. GG, Gg D. gg, GG 12/2/2020 34