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Chapter 10 Sexual Reproduction

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1 Chapter 10 Sexual Reproduction
and Genetics Section 1: Meiosis Section 2: Mendelian Genetics Section 3: Gene Linkage and Polyploidy

2 Chromosomes and Chromosome Number
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Chromosomes and Chromosome Number Human body cells have 46 chromosomes Each parent contributes 23 chromosomes Homologous chromosomes—one of two paired chromosomes, one from each parent

3 Chromosomes and Chromosome Number
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Chromosomes and Chromosome Number Same length Same centromere position Carry genes that control the same inherited traits

4 Haploid and Diploid Cells
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Haploid and Diploid Cells An organism produces gametes to maintain the same number of chromosomes from generation to generation. Human gametes contain 23 chromosomes. A cell with n chromosomes is called a haploid cell. A single set of chromosomes (half the full set of genetic material) A cell that contains 2n chromosomes is called a diploid cell. A cell that has two sets of chromosomes; one set from the father and one from the mother.

5 The sexual life cycle in animals involves meiosis.
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis I The sexual life cycle in animals involves meiosis. Meiosis produces gametes. When gametes combine in fertilization, the number of chromosomes is restored.

6 Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Stages of Meiosis I Reduces the chromosome number by half through the separation of homologous chromosomes Involves two consecutive cell divisions called meiosis I and meiosis II PMAT I and PMAT II

7 Chromosomes replicate.
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis I Interphase Chromosomes replicate. Chromatin condenses. Interphase

8 Pairing of homologous chromosomes occurs.
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis I Prophase I Pairing of homologous chromosomes occurs. Each chromosome consists of two chromatids. Prophase I The nuclear envelope breaks down. Spindles form.

9 Crossing over produces exchange of genetic information.
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis I Prophase I Crossing over produces exchange of genetic information. Crossing over—chromosomal segments are exchanged between a pair of homologous chromosomes.

10 Chromosome centromeres attach to spindle fibers.
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis I Metaphase I Chromosome centromeres attach to spindle fibers. Metaphase I Homologous chromosomes line up at the equator.

11 Homologous chromosomes separate and move
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis I Anaphase I Homologous chromosomes separate and move to opposite poles of the cell. Anaphase I

12 The spindles break down.
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis I Telophase I The spindles break down. Telophase I Chromosomes uncoil and form two nuclei. The cell divides.

13 A second set of phases begins
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis II Prophase II A second set of phases begins as the spindle apparatus forms and the chromosomes condense. Prophase II

14 A haploid number of chromosomes
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis II Metaphase II A haploid number of chromosomes line up at the equator. Metaphase II

15 The sister chromatids are
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis II Anaphase II The sister chromatids are pulled apart at the centromere by spindle fibers and move toward the opposite poles of the cell. Anaphase II

16 The chromosomes reach the poles, and
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis II Telophase II The chromosomes reach the poles, and the nuclear membrane and nuclei reform. Telophase II

17 Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis II Cytokinesis results in four haploid cells, each with n number of chromosomes. Cytokinesis

18 How to tell which process (mitosis, meiosis I, or meiosis II)?
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis How to tell which process (mitosis, meiosis I, or meiosis II)? Look at how the chromosomes are lined up? a. PAIRS….must be Meiosis I b. SINGLE FILE…Mitosis or Meiosis II Look at the chromosome number: # is HAPLOID = must be Meiosis II # is DIPLOID = must be Mitosis

19 The Importance of Meiosis
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis The Importance of Meiosis Meiosis consists of two sets of divisions Produces four haploid daughter cells that are not identical Results in genetic variation

20 Meiosis Provides Variation
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Meiosis Provides Variation Depending on how the chromosomes line up at the equator, four gametes with four different combinations of chromosomes can result. Genetic variation also is produced during crossing over and during fertilization, when gametes randomly combine.

21 Sexual Reproduction v. Asexual Reproduction
Chapter 10 Sexual Reproduction and Genetics 10.1 Meiosis Sexual Reproduction v. Asexual Reproduction Asexual reproduction The organism inherits all of its chromosomes from a single parent. The new individual is genetically identical to its parent. Sexual reproduction Beneficial genes multiply faster over time.

22 Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics How Genetics Began Gregor Mendel was curious of why some pea plants had different physical characteristics (traits). Why they looked different? He observed that the pea plants' traits were often similar to those of their parents, sometimes they were different. The passing of traits to the next generation is called inheritance, or heredity.

23 10.2 Mendelian Genetics He used pea plants because they have many traits that exist in only two forms. (tall/short, green seed/yellow seed) and they were self pollinating He decided to cross plants with opposite forms of a trait, for example, tall plants and short plants.

24 The parent generation is also known as the P generation.
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics The parent generation is also known as the P generation.

25 The second filial (F2) generation is the offspring from the F1 cross.
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics The offspring of this P cross are called the first filial (F1) generation. The second filial (F2) generation is the offspring from the F1 cross.

26 Mendel studied seven different traits.
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Mendel studied seven different traits. Seed or pea color Flower color Seed pod color Seed shape or texture Seed pod shape Stem length Flower position

27 Some of the traits… 10.2 Mendelian Genetics Pod color Seed Color
Plant Height Green Yellow Green Yellow Seed Shape Pod Shape Short Tall Wrinkled Round Smooth Pinched

28 individual factors must control the inheritance of traits in peas.
10.2 Mendelian Genetics MENDEL CONCLUDED: individual factors must control the inheritance of traits in peas. They exist in pairs and the female parent contributes one factor while the male parent contributes the other.

29 Today we call those factors that control traits genes.
10.2 Mendelian Genetics Today we call those factors that control traits genes. They call the different forms of gene alleles. Although his work was not recognized until much later, Mendel is known as the father of genetics for his experiments and papers about his pea plants.

30 Usually we represent these types of traits with letters (TT, Tt, tt)
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Genes in Pairs Allele An alternative form of a single gene passed from generation to generation Dominant Usually we represent these types of traits with letters (TT, Tt, tt) Recessive

31 Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Dominance Dominance is the characteristic of a gene that produces an effect that hides the effect of the recessive gene An organism with two of the same alleles for a particular trait is homozygous. An organism with two different alleles for a particular trait is heterozygous.

32 Genotype and Phenotype
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Genotype and Phenotype An organism’s allele pairs are called its genotype. (Ex: BB, Bb, bb) The observable characteristic or outward expression of an allele pair is called the phenotype. (Ex: blue eyes, blonde hair, etc.)

33 Mendel’s Law of Segregation
Mendel’s first law, the Law of Segregation, has three parts. From his experiments, Mendel concluded that: 1. Plant traits are handed down through “hereditary factors” in the sperm and egg. 2. Because offspring obtain hereditary factors from both parents, each plant must contain two factors for every trait. 3. The factors in a pair segregate (separate) during the formation of sex cells, and each sperm or egg receives only one member of the pair.

34 Mendel’s Law of Segregation
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Mendel’s Law of Segregation Two alleles for each trait separate during meiosis. During fertilization, two alleles for that trait unite. Heterozygous organisms are called hybrids.

35 Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Monohybrid Cross A cross that involves hybrids for a single trait is called a monohybrid cross.

36 Monohybrid Cross Punnett square
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Monohybrid Cross Punnett square Punnett squares can be used to determine the probability of getting a certain trait Remember that results predicted by probability are more likely to be seen when there is a large number of offspring

37 Predict the possible offspring of a cross between two known genotypes
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Punnett Squares Predict the possible offspring of a cross between two known genotypes

38 Dihybrids are heterozygous for both traits.
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Dihybrid Cross The simultaneous inheritance of two or more traits in the same plant is a dihybrid cross. Dihybrids are heterozygous for both traits.

39 Punnett Square—Dihybrid Cross
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Punnett Square—Dihybrid Cross Four types of alleles from the male gametes and four types of alleles from the female gametes can be produced. The resulting phenotypic ratio is 9:3:3:1.

40 Law of Independent Assortment
Chapter 10 Sexual Reproduction and Genetics 10.2 Mendelian Genetics Law of Independent Assortment Random distribution of alleles occurs during gamete formation Genes on separate chromosomes sort independently during meiosis. Each allele combination is equally likely to occur.

41 Genetic Recombination
Chapter 10 Sexual Reproduction and Genetics 10.3 Gene Linkage and Polyploidy Genetic Recombination The new combination of genes produced by crossing over and independent assortment Combinations of genes due to independent assortment can be calculated using the formula 2n, where n is the number of chromosome pairs.

42 Genetic Recombination
Chapter 10 Sexual Reproduction and Genetics 10.3 Gene Linkage and Polyploidy Genetic Recombination Each pea plant cell has 7 pairs of chromosomes, so 27=128 different kinds of sperm possible Humans have 23 pairs of chromosomes, so 223= over 8 million; now when fertilization occurs, 223x 223 = 70 trillion…no wonder each individual is unique!

43 10.3 Gene Linkage and Polyploidy
Chapter 10 Sexual Reproduction and Genetics 10.3 Gene Linkage and Polyploidy Gene Linkage The linkage of genes on a chromosome results in an exception to Mendel’s law of independent assortment because linked genes usually do not segregate independently.

44 Polyploidy is the occurrence of one or more extra sets of all
Chapter 10 Sexual Reproduction and Genetics 10.3 Gene Linkage and Polyploidy Polyploidy Polyploidy is the occurrence of one or more extra sets of all chromosomes in an organism. A triploid organism, for instance, would be designated 3n, which means that it has three complete sets of chromosomes.

45 Chapter Resource Menu Chapter Diagnostic Questions
Sexual Reproduction and Genetics Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Questions Standardized Test Practice biologygmh.com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding feature.

46 Which symbol is used to represent the
Chapter 10 Sexual Reproduction and Genetics Chapter Diagnostic Questions Which symbol is used to represent the number of chromosomes in a gamete? # x r n A B C D CDQ 1

47 Name the person known as the father of genetics.
Chapter 10 Sexual Reproduction and Genetics Chapter Diagnostic Questions Name the person known as the father of genetics. Felix Mendelssohn Gregor Mendel Dr. Reginald Punnett Albert Einstein A B C D CDQ 2

48 Which term refers to the outward expression of an allele pair?
Chapter 10 Sexual Reproduction and Genetics Chapter Diagnostic Questions Which term refers to the outward expression of an allele pair? gamete hybrid phenotype genotype A B C D CDQ 3

49 Segments of DNA that control the production
Chapter 10 Sexual Reproduction and Genetics 10.1 Formative Questions Segments of DNA that control the production of proteins are called _______. chromatids chromosomes genes traits A B C D FQ 1

50 What is the term for a pair of chromosomes
Chapter 10 Sexual Reproduction and Genetics 10.1 Formative Questions What is the term for a pair of chromosomes that have the same length, same centromere position, and carry genes that control the same traits? diploid heterozygous homozygous homologous A B C D FQ 2

51 Chapter 10 Sexual Reproduction and Genetics 10.1 Formative Questions How does the number of chromosomes in gametes compare with the number of chromosomes in body cells? Gametes have 1/4 the number of chromosomes. Gametes have 1/2 the number of chromosomes. Gametes have the same number of chromosomes. Gametes have twice as many chromosomes. A B C D FQ 3

52 What is the name for different forms of a
Chapter 10 Sexual Reproduction and Genetics 10.2 Formative Questions What is the name for different forms of a single gene that are passed from generation to generation? alleles genotypes phenotypes traits A B C D FQ 5

53 Which pair of alleles is heterozygous?
Chapter 10 Sexual Reproduction and Genetics 10.2 Formative Questions Which pair of alleles is heterozygous? RR Rr rr yR A B C D FQ 6

54 In rabbits, gray fur (G) is dominant to black
Chapter 10 Sexual Reproduction and Genetics 10.2 Formative Questions In rabbits, gray fur (G) is dominant to black fur (g). If a heterozygous male is crossed with a heterozygous female, what is the phenotypic ratio of the possible offspring? 1:1 1:2:1 2:1 3:1 A B C D FQ 7

55 Which explains how the shuffling of genes
Chapter 10 Sexual Reproduction and Genetics 10.3 Formative Questions Which explains how the shuffling of genes during meiosis results in billions of possible combinations? crossing over gene linkage genetic recombination independent segregation A B C D FQ 8

56 Two genes on the same chromosome may become separated during meiosis.
Chapter 10 Sexual Reproduction and Genetics 10.3 Formative Questions Two genes on the same chromosome may become separated during meiosis. true false A B FQ 9

57 What is the term for an organism that has one
Chapter 10 Sexual Reproduction and Genetics 10.3 Formative Questions What is the term for an organism that has one or more sets of extra chromosomes in its cells? diploid gamete hybrid polyploid A B C D FQ 10

58 How many chromosomes would a cell have
Chapter 10 Sexual Reproduction and Genetics Chapter Assessment Questions How many chromosomes would a cell have during metaphase I of meiosis if it has 12 chromosomes during interphase? 6 12 24 36 A B C D CAQ 1

59 Which stage of meiosis is illustrated?
Chapter 10 Sexual Reproduction and Genetics Chapter Assessment Questions Which stage of meiosis is illustrated? prophase I interphase anaphase I anaphase II A B C D CAQ 2

60 What is the next step for the chromosomes illustrated?
Chapter 10 Sexual Reproduction and Genetics Chapter Assessment Questions What is the next step for the chromosomes illustrated? Chromosomes replicate. Chromosomes move to opposite poles. Chromosomes uncoil and form two nuclei. Chromosomes line up at the equator. A B C D CAQ 3

61 What is this process called?
Chapter 10 Sexual Reproduction and Genetics Standardized Test Practice What is this process called? fertilization gamete formation inheritance reproduction A B C D STP 1

62 Standardized Test Practice
Chapter 10 Sexual Reproduction and Genetics Standardized Test Practice Before meiosis I, the sister chromatids of this chromosome were identical. What process caused a change in a section of one chromatid? DNA replication crossing over synapsis telophase A B C D STP 2

63 At what stage is the chromosome number reduced from 2n to n?
Chapter 10 Sexual Reproduction and Genetics Standardized Test Practice At what stage is the chromosome number reduced from 2n to n? prophase I metaphase I anaphase I meiosis II A B C D STP 3

64 To which step in this process does the law of segregation apply?
Chapter 10 Sexual Reproduction and Genetics Standardized Test Practice To which step in this process does the law of segregation apply? grows into plant gamete formation fertilization seed development A B C D STP 4

65 1/4 1/2 1 For human eye color, brown is dominant and
Chapter 10 Sexual Reproduction and Genetics Standardized Test Practice For human eye color, brown is dominant and blue is recessive. If a husband is heterozygous and his wife has blue eyes, what is the probability that their child will have blue eyes? 1/4 1/2 1 A B C D STP 5

66 Section 1 Vocabulary gene homologous chromosome gamete haploid
Chapter 10 Sexual Reproduction and Genetics Vocabulary Section 1 gene homologous chromosome gamete haploid fertilization diploid meiosis crossing over

67 Section 2 Vocabulary genetics allele dominant recessive homozygous
Chapter 10 Sexual Reproduction and Genetics Vocabulary Section 2 genetics allele dominant recessive homozygous heterozygous genotype phenotype law of segregation hybrid law of independent assortment

68 Section 3 Vocabulary genetic recombination polyploidy Chapter 10
Sexual Reproduction and Genetics Vocabulary Section 3 genetic recombination polyploidy


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