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

2. In this lesson, you will learn to:
Lesson Objectives
In this lesson, you will learn to:
Examine genetics and its role in fetal development
Identify common genetic disorders
Analyze genetic research and technology and their impact on the health of people with genetic disorders

3. Inheriting Traits Heredity
No two individuals are exactly alike. Even identical twins have some differences.
Heredity 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.

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

5. DNA Heredity All living things are made of 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.

6. Genetics and Fetal Development
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.

7. Genetics and Fetal Development
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.

8. Genetics and Fetal Development
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.

9. Mutation Genetic Disorders
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.

10. Common Human Genetic Disorders

11. Test for Genetic Disorders
Two common technologies used to test for genetic disorders are:
Amniocentesis
Chorionic villi sampling (CVS)

12. Genetic Counseling Genetic Disorders
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.

13. Genetic Research to Cure Disease
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.

14. Genetic Research to Cure Disease
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.

15. Quick Review
Choose the appropriate option.
Q. The passing of traits from parents to their children is called _________.
heredity
DNA
genes
genetic disorder

16. A. 1. heredity Quick Review - Answer
The passing of traits from parents to their children is called heredity.
Click Next to attempt another question.

17. Q. Which of the following is not a genetic disorder?
Quick Review
Choose the appropriate option.
Q. Which of the following is not a genetic disorder?
Sickle-cell anemia
Cirrhosis
Cystic fibrosis
Tay-Sachs disease

18. A. 2. cirrhosis Quick Review - Answer
Genetic disorders do not include cirrhosis.
Click Next to attempt another question.

19. Quick Review
Choose the appropriate option.
Q. Amniocentesis is a procedure in which a syringe is inserted through a pregnant female’s abdominal wall and into the amniotic fluid surrounding the developing fetus.
True
False

20. Quick Review - Answer
A. True. Amniocentesis is a procedure in which a syringe is inserted through a pregnant female’s abdominal wall and into the amniotic fluid surrounding the developing fetus.
Click Next to attempt another question.

21. Quick Review
Choose the appropriate option.
Q. Fetal development is the making of a new and unique human being. Genetics play only a marginal role in the development of the fetus.
True
False

22. Quick Review - Answer
A. False. Fetal development is the making of a new and unique human being. Genetics play an important role in the development of the fetus.
Click Next to attempt another question.

23. End of Lesson 3
Click Home to view the Main menu.

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

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

26. Inheriting Traits Heredity
No two individuals are exactly alike. Even identical twins have some differences.
Heredity 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 is the passing of traits that are biological from parents to their children.

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

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

29. DNA Heredity All living things are made of 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.

30. Mutation Genetic Disorders
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.
A genetic disorder is a disorder caused partly or completely by a defect in genes.

31. Test for Genetic Disorders
Two common technologies used to test for genetic disorders are:
Amniocentesis
Chorionic villi sampling (CVS)
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.

32. 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.
Two common technologies used to test for genetic disorders are:
Amniocentesis
Chorionic villi sampling (CVS)

33. Genetic Research to Cure Disease
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.

34. A. Correct! Genetic disorders do not include the following: cirrhosis.
Quick Review - Answer
A. Correct! Genetic disorders do not include the following: cirrhosis.
Click Next to attempt another question.

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

36. Quick Review - Answer
A. Correct! Amniocentesis is a procedure in which a syringe is inserted through a pregnant female’s abdominal wall and into the amniotic fluid surrounding the developing fetus.
Click Next to attempt another question.

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

38. Quick Review - Answer
A. Correct! Fetal development is the making of a new and unique human being. Genetics play an important role in the development of the fetus.
Click Next to attempt another question.

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