2. Lesson 3 Family members often share a strong physical resemblance. What inherited characteristics are visible in this family? Heredity and Genetics

3. Lesson 3 In this lesson, you’ll learn to: Explain the significance of genetics and its role in fetal development. Identify common genetic disorders. Explain how genetic research and technology has impacted the health status of families and individuals with genetic disorders. Lesson Objectives

4. Lesson 3 Inheriting Traits No two individuals are exactly alike. Even identical twins have some differences. HeredityHeredity is a significant factor that influences the way an individual develops. Some traits that you inherit from your parents are your eye and hair color. Environment can also influence inherited traits. Heredity

5. Lesson 3 Chromosomes and Genes Most cells of your body contain a nucleus—the cell’s control center. Inside each nucleus is a set of chromosomes.chromosomes Most cells in the body contain 46 chromosomes arranged as 23 pairs. Sections of chromosomes, called genes, carry codes for specific traits.genes Like chromosomes, genes occur in pairs. One gene from each pair is inherited from each parent. Heredity

6. Lesson 3 DNA All living things are made of DNA.DNA Chemical compounds, called bases, make up the structure of DNA. The order of the bases is called the genetic code. Cells use the genetic code to make proteins. Unless you have an identical twin, your DNA is different from that of any other person. Heredity

7. Lesson 3 Dominant and Recessive Genes At least one pair of genes is responsible for each human trait. Some genes are dominant, and others are recessive. The traits of dominant genes generally appear in offspring whenever they are present. The traits of recessive genes usually appear only when dominant genes are not present. Genetics and Fetal Development

8. Lesson 3 Genes and Gender In humans, one pair of chromosomes determines the gender of an individual. If you are female, these two chromosomes look exactly alike and are called X chromosomes. If you are male, the two chromosomes differ—one is shorter than the other and is called a Y chromosome. Genetics and Fetal Development

9. Lesson 3 Genetic Makeup Sperm contain an X or a Y chromosome. Eggs have only an X chromosome. The gender of a child is determined by which type of sperm—X or Y—unites with an egg. Genetics and Fetal Development

10. Lesson 3 Mutation Sometimes the genes that an individual inherits contain a mutation, or abnormality, in the base sequence of the genetic code. Often the mutation has little or no effect on the individual, but sometimes the mutation can result in defects or other health problems. Some genetic disorders, such as those that cause birth defects, are apparent right away.genetic disorders Genetic Disorders

11. Lesson 3 Common Human Genetic Disorders Genetic Disorders

12. Lesson 3 Test for Genetic Disorders Two common technologies used to test for genetic disorders are: 1. AmniocentesisAmniocentesis 2. Chorionic villi sampling (CVS)Chorionic villi sampling (CVS) Genetic Disorders

13. Lesson 3 Genetic Counseling Research for diagnosing, preventing, and treating genetically related diseases has resulted in a wide variety of programs. Genetic counselors can advise families about the probability of having a child with a genetically related disease. They also can guide families of children with genetic disorders about possible treatment options. Genetic Disorders

14. Lesson 3 Gene Therapy When the defective gene is replaced with a normal one using the gene therapy, the cells with the new gene begin to makegene therapy the missing substance. The practice of placing fragments of DNA from one organism into another is called genetic engineering, and it is considered highly experimental. Genetic diseases for which scientists are researching gene therapies include cystic fibrosis and various types of cancer. Genetic Research to Cure Disease

15. Lesson 3 Genetically Engineered Drugs Genes used to treat disease aren’t usually inserted directly into human beings. Instead they are placed into other organisms, causing them to produce substances that can be used to treat human diseases and disorders. Genetically produced medicines include treatments for burns and ulcers, growth defects, and ovarian and breast cancers. Factor VIII medicines treat hemophilia. Genetic engineering also is used to produce some vaccines that prevent diseases. Genetic Research to Cure Disease

16. Lesson 3 Q. The passing of traits from parents to their children is called _________. 1.heredity 2.DNA 3.genes 4.genetic disorder Choose the appropriate option. Quick Review

17. Lesson 3 A. The passing of traits from parents to their children is called heredity. Click Next to attempt another question. Quick Review - Answer

18. Lesson 3 Provide a short answer to the question given below. Q. Name three human genetic disorders. Click Next to view the answer. Quick Review

19. Lesson 3 A. Some human genetic disorders are: Sickle-cell anemia Tay-Sachs disease Cystic fibrosis Down syndrome Hemophilia Phenylketonuria (PKU) Click Next to attempt another question. Quick Review - Answer

20. Lesson 3 Provide a short answer to the question given below. Q. Explain the difference between amniocentesis and chorionic villi sampling (CVS). Click Next to view the answer. Quick Review

21. Lesson 3 A. Amniocentesis is a procedure in which a syringe is inserted through a pregnant female’s abdominal wall into the amniotic fluid surrounding the developing fetus. Chorionic villi sampling (CVS) is a procedure in which a small piece of membrane is removed from the chorion, a layer of tissue that develops into the placenta. Click Next to attempt another question. Quick Review - Answer

22. Lesson 3 Explain the significance of genetics and its role in fetal development. Analyze the following question. Quick Review

23. Lesson 3 A. Correct! The passing of traits from parents to their children is called heredity. Click Next to attempt another question. Quick Review - Answer

24. Lesson 3 You have answered the question incorrectly. Go back to try again, or click Next to view the correct answer. Quick Review - Answer

25. Lesson 3 No two individuals are exactly alike. Even identical twins have some differences. HeredityHeredity is a significant factor that influences the way an individual develops. Some traits that you inherit from your parents are your eye and hair color. Environment can also influence inherited traits. Inheriting Traits The passing of traits from parents to their children is called heredity. Heredity

26. Lesson 3 Most cells of your body contain a nucleus—the cell’s control center. Inside each nucleus is a set of chromosomes.chromosomes Most cells in the body contain 46 chromosomes arranged as 23 pairs. Sections of chromosomes, called genes, carry codes for specific traits.genes Like chromosomes, genes occur in pairs. One gene from each pair is inherited from each parent. Chromosomes and Genes A chromosome is a threadlike structure found within the nucleus of a cell that carries the code for inherited traits. Heredity

27. Lesson 3 Most cells of your body contain a nucleus—the cell’s control center. Inside each nucleus is a set of chromosomes.chromosomes Most cells in the body contain 46 chromosomes arranged as 23 pairs. Sections of chromosomes, called genes, carry codes for specific traits.genes Like chromosomes, genes occur in pairs. One gene from each pair is inherited from each parent. Chromosomes and Genes A gene is the basic unit of heredity. Heredity

28. Lesson 3 DNA All living things are made of DNA.DNA Chemical compounds, called bases, make up the structure of DNA. The order of the bases is called the genetic code. Cells use the genetic code to make proteins. Unless you have an identical twin, your DNA is different from that of any other person. DNA, or deoxyribonucleic acid, is the chemical unit that makes up chromosomes. Heredity

29. Lesson 3 Sometimes the genes that an individual inherits contain a mutation, or abnormality, in the base sequence of the genetic code. Often the mutation has little or no effect on the individual, but sometimes the mutation can result in defects or other health problems. Some genetic disorders, such as those that cause birth defects, are apparent right away.genetic disorders Mutation A genetic disorder is a disorder caused partly or completely by a defect in genes. Genetic Disorders

30. Lesson 3 Two common technologies used to test for genetic disorders are: 1. AmniocentesisAmniocentesis 2. Chorionic villi sampling (CVS)Chorionic villi sampling (CVS) Test for Genetic Disorders Amniocentesis is a procedure in which a syringe is inserted through a pregnant female’s abdominal wall into the amniotic fluid surrounding the developing fetus. Genetic Disorders

31. Lesson 3 Two common technologies used to test for genetic disorders are: 1. AmniocentesisAmniocentesis 2. Chorionic villi sampling (CVS)Chorionic villi sampling (CVS) Test for Genetic Disorders Chorionic villi sampling (CVS) is a procedure in which a small piece of membrane is removed from the chorion, a layer of tissue that develops into the placenta. Genetic Disorders

32. Lesson 3 Gene Therapy When the defective gene is replaced with a normal one using the gene therapy, the cells with the new gene begin to make the missing substance. The practice of placing fragments of DNA from one organism into another is called genetic engineering, and it is considered highly experimental. Genetic diseases for which scientists are researching gene therapies include cystic fibrosis and various types of cancer. Gene therapy is the process of inserting normal genes into human cells to correct genetic disorders. Genetic Research to Cure Disease