Heredity: Monohybrid Cross 5.3

Heredity: Monohybrid Cross 5.3 1. Gregor Mendel made a major contribution to Biology. He learned that each kind of cross-breeding experiment produced offspring with a certain ________ of the traits he was studying. Ex: In his F1 generation, he found that all of the offspring expressed the ____________ phenotype; The F2 generation expressed a ratio of ____ dominant phenotypes to ____ recessive phenotype. He also found he could predict the outcome of a cross by using ____________. ratio dominant 3 1 probability

Probability 2. Probability is the ___________ that something will happen. It can be expressed as a: Fraction (1/2) Decimal (0.5) Percent (50%) Probability = number of all possible outcomes What is the probability that a die will land the1? ______________ likelihood 1/6, 1:6

Important Terms 3. A ___________ cross is a cross-breeding experiment that can be used to determine how ____ trait (pair of genes) can be inherited. 4. A ____________ can be used to determine the expected outcome of a cross. It is named after its inventor, Reginald __________. 5. The _________ and __________ ratios can be found using a Punnett square. monohybrid 1 Punnett square Punnett genotypic phenotypic

Cross Experiment 6. The genotypic ratio is the ratio of genotypes among the offspring of a cross. It states the __________ of individuals with each different genotype observed among the offspring. 7. The phenotypic ratio is the ratio of phenotypes among the offspring of a cross. It states the __________ of individuals with each different phenotype observed among the offspring. number number

Seed Shape in Garden Peas 8. Use a monohybrid cross to study the inheritance of seed shape in garden peas. A round seed shape is the dominant trait (R) and a wrinkled seed shape is the recessive seed shape (r). Generation P F1 Round Wrinkled X RR rr Genotypic ratio: Genotypic Frequency: Phenotypic Ratio: Phenotypic Frequency: 4:4 Rr Homozygous Dominant Homozygous Recessive r r 100% Rr Rr R 4:4 Round 100% Round

Seed Shape in Garden Peas Generation F2 Genotypic ratio: Genotypic Frequency: Phenotypic Ratio: Phenotypic Frequency: 1RR: 2Rr: 1rr R r 25% RR, 50% Rr, 25% rr RR Rr rr R r 3 Round: 1 Wrinkled 75% Round 25% Wrinkled

Assessment 9. What do the letters at the top and left side of a Punnett square represent? ________________________________________ 10. What do the boxes in a Punnett square represent? The parent’s alleles in each gamete Possible offspring genotypes