1. Standardized Test Prep Image and Math Focus Bank
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Chapter Presentation
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Standardized Test Prep
Image and Math Focus Bank
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2. Chapter 5
Section 1 Mendel and His Peas
Objectives
Explain the relationship between traits and heredity.
Describe the experiments of Gregor Mendel.
Explain the difference between dominant and recessive traits.

3. Chapter 5 Who Was Gregor Mendel?
Section 1 Mendel and His Peas
Who Was Gregor Mendel?
Gregor Mendel was born in 1822 in Heinzendorf, Austria.
At age 21, Mendel entered a monastery. He performed many scientific experiments in the monastery garden.
Mendel discovered the principles of heredity, the passing of traits from parents to offspring.

4. Unraveling the Mystery
Chapter 5
Section 1 Mendel and His Peas
Unraveling the Mystery
Mendel used garden pea plants for his experiments.
Self-Pollinating Peas have both male and female reproductive structures. So, pollen from one flower can fertilize the ovule of the same flower.
When a true-breeding plant self pollinates, all of the offspring will have the same trait as the parent.

5. Unraveling the Mystery, continued
Chapter 5
Section 1 Mendel and His Peas
Unraveling the Mystery, continued
Pea plants can also cross-pollinate. Pollen from one plant fertilizes the ovule of a flower on a different plant.
The image below shows cross-pollination and self-pollination.

6. Unraveling the Mystery, continued
Chapter 5
Section 1 Mendel and His Peas
Unraveling the Mystery, continued
Characteristics Mendel studied only one pea characteristic at a time. A characteristic is a feature that has different forms in a population.
Different forms of a characteristic are called traits.

7. Unraveling the Mystery, continued
Chapter 5
Section 1 Mendel and His Peas
Unraveling the Mystery, continued
Mix and Match Mendel was careful to use plants that were true breeding for each of the traits he was studying. By doing so, he would know what to expect if his plants were to self-pollinate.

8. Mendel’s First Experiments
Chapter 5
Section 1 Mendel and His Peas
Mendel’s First Experiments
Mendel crossed pea plants to study seven different characteristics.
Mendel got similar results for each cross. One trait was always present in the first generation, and the other trait seemed to disappear.
Mendel called the trait that appeared the dominant trait. The trait that seemed to fade into the background was called the recessive trait.

9. Chapter 5 Mendel’s Second Experiments
Section 1 Mendel and His Peas
Mendel’s Second
Experiments
To find out more about recessive traits, Mendel allowed the first-generation plants to self-pollinate.
In each case some of the second-generation plants had the recessive trait.

10. Mendel’s Second Experiments, continued
Chapter 5
Section 1 Mendel and His Peas
Mendel’s Second Experiments, continued
Ratios in Mendel’s Experiments The recessive trait did not show up as often as the dominant trait.
Mendel decided to figure out the ratio of dominant traits to recessive traits.

11. Mendel’s Second Experiments, continued
Chapter 5
Section 1 Mendel and His Peas
Mendel’s Second Experiments, continued
In all cases the ratio was about 3:1 dominant : recessive.

12. Mendel’s Second Experiments, continued
Chapter 5
Section 1 Mendel and His Peas
Mendel’s Second Experiments, continued
Gregor Mendel – Gone But Not Forgotten Mendel realized that his results could be explained only if each plant had two sets of instructions for each characteristic.
Mendel’s work opened the door to modern genetics.

13. Chapter 5
Section 2 Traits and Inheritance
Objectives
Explain how genes and alleles are related to genotype and phenotype.
Use the information in a Punnett square.
Explain how probability can be used to predict possible genotypes in offspring.
Describe three exceptions to Mendel’s observations.

14. Chapter 5
Section 2 Traits and Inheritance
A Great Idea
Mendel knew that there must be two sets of instructions for each characteristic.
The instructions for an inherited trait are called genes.
The different forms (often dominant and recessive) of a gene are alleles.
Phenotype An organism’s appearance is known as its phenotype. Genes affect the phenotype.

15. Chapter 5 A Great Idea, continued
Section 2 Traits and Inheritance
A Great Idea, continued
Genotype The combination of inherited alleles together form an organism’s genotype.
Punnett Squares are used to organize all the possible genotype combinations of offspring from particular parents.

16. Chapter 5
Section 2 Traits and Inheritance

17. Chapter 5 What Are the Chances?
Section 2 Traits and Inheritance
What Are the Chances?
Probability is the mathematical chance that something will happen.
Probability is most often written as a fraction of percentage.

18. Calculating Probability
Chapter 5
Section 2 Traits and Inheritance
Calculating Probability

19. What Are the Chances?, continued
Chapter 5
Section 2 Traits and Inheritance
What Are the Chances?, continued
Genotype Probability To have white flowers, a pea plant must receive a p allele from each parent. Each offspring of a Pp Pp cross has a 50% chance of receiving either allele from either parent. So, the probability of inheriting two p alleles is 1/2  1/2, which equals 1/4, or 25%.

20. Chapter 5 More About Traits
Section 2 Traits and Inheritance
More About Traits
Incomplete Dominance Researchers have found that sometimes one trait is not completely dominant over another.
One Gene, Many Traits Sometimes one gene influences more than one trait.
Many Genes, One Trait Some traits, such as the color of your skin, hair, and eyes, are the result of several genes acting together.

21. More About Traits, continued
Chapter 5
Section 2 Traits and Inheritance
More About Traits, continued
The Importance of Environment Genes aren’t the only influences on traits. A combination of things determine an individual’s characteristics.
Your environment also influences how you grow.
Lifestyle choices can also affect a person’s traits.

22. Chapter 5
Section 3 Meiosis
Objectives
Explain the difference between mitosis and meiosis.
Describe how chromosomes determine sex.
Explain why sex-linked disorders occur in one sex more often than in the other.
Interpret a pedigree.

23. Chapter 5 Asexual Reproduction
Section 3 Meiosis
Asexual Reproduction
In asexual reproduction, only one parent cell is needed. The structures inside the cell are copied, and then the parent cell divides, making two exact copies.
This type of cell reproduction is called mitosis. Most of the cells in your body and most single-celled organisms reproduce this way.

24. Chapter 5
Section 3 Meiosis
Mitosis

25. Chapter 5 Sexual Reproduction
Section 3 Meiosis
Sexual Reproduction
In sexual reproduction, two parent cells (sex cells) join together to form offspring that are different from both parents.
Chromosomes that carry the same sets of genes are called homologous chromosomes.
Each sex cell has only one of the chromosomes from the homologous pair.

26. Sexual Reproduction, continued
Chapter 5
Section 3 Meiosis
Sexual Reproduction, continued
Meiosis Sex cells are made during meiosis.
Meiosis is a copying process that produces cells with half the usual number of chromosomes.

27. Chapter 5 Meiosis Section 3 Meiosis
Click below to watch the Visual Concept.
You may stop the video at any time by pressing the Esc key.
Visual Concept

28. Genes are located on chromosomes.
Chapter 5
Section 3 Meiosis
Sexual Reproduction, continued
Genes and Chromosomes Walter Sutton studied meiosis in sperm cells in grasshoppers.
Using his observations and his knowledge of Mendel’s work, Sutton proposed that:
Genes are located on chromosomes.

29. Chapter 5 The Steps of Meiosis
Section 3 Meiosis
The Steps of Meiosis
During meiosis, chromosomes are copied once, and then the nucleus divides twice.
The resulting sex cells (sperm and eggs) have half the number of chromosomes of a normal body cell.

30. Chapter 5
Section 3 Meiosis

31. Chapter 5
Section 3 Meiosis

32. Chapter 5 Meiosis and Mendel
Section 3 Meiosis
Meiosis and Mendel
The steps of meiosis explain Mendel’s results. The following slide shows what happens to a pair of homologous chromosomes during meiosis and fertilization.

33. Chapter 5
Section 3 Meiosis

34. Meiosis and Mendel, continued
Chapter 5
Section 3 Meiosis
Meiosis and Mendel, continued
Sex Chromosomes carry genes that determine sex.
Human females have two X chromosomes.
Human males have one X chromosome and one Y chromosome.

35. Meiosis and Mendel, continued
Chapter 5
Section 3 Meiosis
Meiosis and Mendel, continued
Sex-Linked Disorders The genes for certain disorders, such as colorblindness, are carried on the X chromosome.
Genetic Counseling Genetic counselors use pedigrees to trace traits through generations of a family. These diagrams can often predict if a person is a carrier of a hereditary disease.
Selective Breeding In selective breeding, organisms with desirable characteristics are mated.

36. Chapter 5 Concept Map alleles offspring parents genotype phenotype
Heredity
Concept Map
Use the terms below to complete the concept map on the next slide.
alleles
parents
phenotype
genes
offspring
genotype
characteristics
dominant

37. Chapter 5
Heredity

38. Chapter 5
Heredity

39. End of Chapter 5 Show Header – dark yellow 24 points Arial Bold
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40. Chapter 5 CNN Videos Science, Technology, and Society: BioDiesel
Heredity
CNN Videos
Science, Technology, and Society: BioDiesel
Science, Technology, and Society: Bioengineered Plants

41. Interpreting Graphics
Chapter 5
Standardized Test Preparation
Interpreting Graphics
The Punnett square below shows a cross between two flowering plants. Use this Punnett square to answer the questions that follow.

42. Chapter 5
Standardized Test Preparation
1. What is the genotype of the offspring represented in the upper left-hand box of the Punnett square?
A RR
B Rr
C rr
D rrr

43. Chapter 5
Standardized Test Preparation
1. What is the genotype of the offspring represented in the upper left-hand box of the Punnett square?
A RR
B Rr
C rr
D rrr

44. Chapter 5
Standardized Test Preparation
2. What is the genotype of the offspring represented in the lower right-hand box of the Punnett square?
F RR
G Rr
H rr
I rrr

45. Chapter 5
Standardized Test Preparation
2. What is the genotype of the offspring represented in the lower right-hand box of the Punnett square?
F RR
G Rr
H rr
I rrr

46. Chapter 5
Standardized Test Preparation
3. What is the ratio of Rr (purple-flowered plants) to rr (white-flowered plants) in the offspring?
A 1:3
B 2:2
C 3:1
D 4:0

47. Chapter 5
Standardized Test Preparation
3. What is the ratio of Rr (purple-flowered plants) to rr (white-flowered plants) in the offspring?
A 1:3
B 2:2
C 3:1
D 4:0

48. Chapter 5
Section 1 Mendel and His Peas

49. Chapter 5
Section 1 Mendel and His Peas

50. Chapter 5
Section 1 Mendel and His Peas

51. Chapter 5
Section 1 Mendel and His Peas

52. Chapter 5
Section 1 Mendel and His Peas

53. Chapter 5
Section 2 Traits and Inheritance

54. Chapter 5
Section 3 Mitosis

55. Chapter 5
Section 3 Mitosis

56. Chapter 5
Standardized Test Preparation