Yes, heterozygous organisms can pass a dominant allele onto the offspring. Only one dominant allele is needed to have the dominant genotype.

Transcription

1 Name: Period: Unit 4: Inheritance of Traits Scopes 9-10: Inheritance and Mutations 1. What is an organism that has two dominant alleles for a trait? Homozygous dominant Give an example of an organism with this genotype. XX 2. What is an organism that has two recessive alleles for a trait? Homozygous recessive Give an example of an organism with this genotype. xx 3. What is an organism that has one dominant and one recessive allele for a trait? Heterozygous Give an example of an organism with this genotype. Xx 4. In a Punnett square, dominant alleles are represented by Capital letters, while recessive alleles are represented by lower case letters. 5. In a certain breed of mice, agouti fur color (A) is dominant over black fur color (a). Complete the Punnett square below to show the possible offspring combinations that would result if a mouse that is heterozygous for fur color is crossed with a mouse that is homozygous recessive for fur color. Aa Aa aa aa 6. Explain whether or not two heterozygous organisms can produce offspring with the dominant trait? Explain your answer in complete sentences. Yes, heterozygous organisms can pass a dominant allele onto the offspring. Only one dominant allele is needed to have the dominant genotype.

2 In bunnies, floppy ears (E) are dominant over straight ears (e). Use the following Punnett square to answer the questions below. 7. Define genotype actual genetic makeup 8. What are the possible genotypes of the bunny offspring? Ee,ee 9. Define phenotype physical appearence 10. What are the possible phenotypes of the bunny offspring? floppy and straight 11. How much is each box worth on a Punnett square? 25% 12. What would be the percent chance that an offspring would have straight ears? 50% 13. What is one of the most immediate results of a gene mutation? Proteins are rearanged 14. In pea plants, the smooth coat allele (R) is dominant over the wrinkled coat allele (r). Complete the Punnett square with a cross between two heterozygous plants. Draw a picture of the pea (smooth or wrinkled) with each genotype.

3 RR Rr Rr rr 15. The following Punnett square shows a cross between two guinea pigs with different fur color, white (H) and brown (h). Write yes or no on the following lines to show whether or not the information in the Punnett square supports the statement. Hh hh Hh hh A. no The trait of white fur is an advantage to guinea pigs for avoiding predators. B. no Eventually, all of the guinea pigs that descend from this pack will have brown fur. C. no Two white guinea pigs can t produce offspring with brown fur. D. yes The trait of white fur is dominant over the trait of brown fur.

4 16. The gene that controls the production of hemoglobin produces a protein responsible for the binding of oxygen to red blood cells in humans. What would a person s body have difficulty doing if they had a mutation to this gene? Getting oxygen to the rest of the body 17. What is the primary function of genes? Create proteins that code for our traits 18. Write whether the following scenarios describe a harmful, helpful, or neutral mutation. A. neutral The frequency of the mutation goes up and down with no observable effect on the health of a population B. helpful In a given population, individuals that possess this mutation have a greater rate of reproduction. C. harmful The mutation is higher in populations of organisms that produce fewer offspring and have shorter life spans. D. helpful The frequency of the mutation in a population, once it first appears, tends to increase over time. 19. A certain genetic mutation is found with a high frequency in populations of humans living in places that experienced a deadly disease in the past. This same mutation is rare in places that have no history of the disease. Based on how genes work, write true or false, and explain your reasoning. A. false Humans with this mutation develop this disease and then spread it to other humans without the mutation. This has nothing to do with mustations B. false The disease causes the genetic material of humans to mutate just before it causes their disease. Mutations are random and cant be forced to mutate

5 C. false The genetic mutation was present in all populations but did not get passed on in places where humans did not contract the disease. Mutations are passed on regardless of where D. true This genetic mutation codes for the production of a protein that provides resistance to the disease. Only people that had the mutation survived and thus were passed onto the offspring. Making the mutation more common in those areas that had the disease. 20. Students are modeling how genes produce proteins by using wooden tiles with letters to represent the genes. In this model, the words that the combination of letters produce represent the proteins. Write down what would be produced in the following scenarios. A. Combining many different words to create a complete message protein B. Creating any word that is spelled exactly the same way forward and backward inversion C. Changing one or more of the letters so that they spell a different word or no word at all substitution D. Making different words, with a certain number of letters, that have the same meaning insertion 21. In humans, the protein CFTR regulates the components of sweat, digestive fluids, and mucus. Humans can have a normal form of the gene or a mutated form. Write yes next to the following scenarios if they prove the CFTR gene is harmful, write no if they do not.

6 A. no Most illnesses have symptoms associated with sweat, digestive fluids, and mucus. B. yes Individuals who inherit the mutated form of the gene usually develop serious health problems. C. no Healthy individuals, with the normal form of the CFTR gene, can pass on a mutated form. D. no Both the normal and the mutated form of the CFTR gene can be found in healthy humans. 22. Sickle cell anemia is a disease in which red blood cells become irregularly shaped. The disease is caused by the presence of an incorrect amino acid in a certain protein. What had to change in order for an incorrect amino acid to be placed in the protein? DNA 23. What are structural changes to genes? mutation 24. What are large molecules made of amino acids? protein 25. Genetic mutations can affect the health and development of organisms. Complete the chart on the answer sheet with the different ways mutations can affect organisms. Affect of Mutation Harmful beneficial Description of How the Mutation Affects the Survival of Organisms Hurts and organisms rate of survival Helps an organism survive nuetral Does not help or hurt an organisms survival

7 26. Three types of mutations that can take place are insertion, substitution, or deletion. Using the original sequence below as a guide, complete the table on the answer sheet with the correct type of mutation. Original sequence. THE MAD RAT HIT THE CAT THE MAD RAT HBI TTH ECA T THE MAR ATH ITT HEC AT THE MAB RAT HIT THE CAT insertion deletion substitution