Genetics Test Study Guide

1. Genetics Test Study Guide 11/16/07

2. Know definitions for following words: 1. pedigree- tool for tracing a trait through a family 2.heterozygous- an organism with two different alleles for a trait 3. genotype- genetic makeup of an organism 4. phenotype- physical appearance of an organism 5. probability- helps determine the chance that something will occur

3. 6. incomplete dominance- when an intermediate form is expressed in offspring 7. multiple alleles- when more than two alleles control a trait 8. polygenic inheritance- when a group of gene pairs act together 9. punnett square- a genetics tool that uses letters to represent dominant and recessive alleles 10. homozygous- when there are two alleles that are exactly the same 11. heredity- passing of traits from parents to offspring

4. 12. dominant factor- a factor that covers up another factor 13. recessive factor – a factor that seems to disappear 14. alleles- the different forms a gene has for a trait 15. genetics- study of heredity 16. Homozygous traits will look like two upper case letters or two lower case letters TT ,tt 17.Punnett square shows you all the ways alleles combine

5. 18. Human blood types- A, B, AB and O 19. Blood type is controlled by 3 alleles 20. Capital letters stand for and lower case stands for a 21. Recessive genetic disorder examples are 22. Mendel called plants that received different alleles for a trait from each parent a 23. Father of Genetics is dominant trait recessive trait cystic fibrosis and hemophilia hybrid Gregor Mendel

6. 24. Purebred animals that show variations in coat color is an example of 25. Every sex cell has alleles for each trait 26. If a human baby has 2- X chromosomes the baby is a ; if it has an X and a Y chromosome it is a 27. A useful segment of DNA is inserted into a bacterium to make 28. In, scientists are experimenting with methods to change the arrangement of DNA in a gene incomplete dominance 2 girl boy recombinant DNA genetic engineering

7. 29. A purple flower (Pp) and a white flower (pp) could produce purple flowers • Describe the advantage of genetically engineered tomatoes. • They can be picked green and transported great distances before they ripen completely, so that they are ripe when at the market for purchase • If a family has four children, 2 girls, 2 boys, and only one girl and one boy are colorblind, are their parents colorblind? • The father is colorblind and the mother is a carrier 2 Xc Y x Xc XcXc XcY X XcX XY

8. 32. Who is more likely to be colorblind, girls or boys? 33. Offspring with homozygous alleles received how many alleles from each parent? 34. What possible genotypes will the offspring have if the parents’ blood types are O and AB? 32. Who is more likely to be colorblind, girls or boys? 33. Offspring with homozygous alleles received how many alleles from each parent? 34. What possible genotypes will the offspring have if the parents’ blood types are O and AB? boys one AO or BO A B O AO BO O AO BO

9. Why do cystic fibrosis patients have to have their backs pounded on as part of their therapy? • to break the mucus in their lungs to breathe easier 36. One day it will be important for scientists to correct damaged genes in babies before they are born. Why? It may result in a genetic cure for the disorder 37. is one disease that is already being treated by use of recombinant DNA, a method of genetic engineering. Diabetes

10. 38. You are looking at four purple flowers. What are their phenotypes and genotypes? • Phenotype is purple and just by looking you could not tell their genotypes but it could be PP or Pp • is when you select plants or animals with the most desired traits to breed for the next generation. • 40. is when a normal allele is placed into a virus, which delivers it when it infects its target • cells. Selective breeding Gene therapy

11. 41. Name traits that are a result of polygenic inheritance. human height, human eye color, human skin color, human hair color, grain color in wheat, milk production in cows, egg production in chickens 42. Why was Mendel’s predictions for dominant and recessive traits so accurate? He worked with a large number of plants (over 30,000) and concentrated on one trait at a time and he kept a record of the results. 43. How can Punnett Squares predict results of crossbreeding in plants? It shows all the ways in which alleles for a particular trait can be combined

12. 44. How many crosses of red and white four-o’clock flowers would you need to find out all the possible phenotypes for color of flowers? You would need 2, the first cross would be red with white and the second cross would be pink with pink which would give you red, white and pink phenotypes 45. Write a pedigree for a family (parents and four children) in which one girl and one boy are color-blind while one boy and one girl are not. Xc Y Xc XcXc XcY X XcX XY

13. 46.If two people are heterozygous for sickle cell anemia, what are the chances that their children will have the disease?S = non sickle cell anemia and s = sickle cell anemia +_________________________________________________________________ ______________________________________________________________________________________

14. 47.Family pedigree of color-blindness. How is the disease inherited? Disease is sex linked andinherited on the X chromosome. Mother is a carrier.