Exam 6: Learning Objectives for Chapters 13 and 14

Exam Format

  • The exam includes:
    • Multiple-choice questions
    • True-False questions (correct the false)
    • Fill-in-the-blank questions
  • Types of Questions:
    • 60-75% of the test is MC/TF/F
    • 25-40% will be short answer
  • Potential to interpret diagrams or figures

Chapter 13 Learning Objectives

Meiosis Terminology

  • Sex Chromosome: Chromosomes that dictate sex (X and Y).
  • Autosome: Non-sex chromosomes that determine other traits.
  • Homologous Chromosomes (Homologs): Chromosomes that have the same genes at the same loci but may have different alleles.
  • Genome: The complete set of genetic material in an organism.
  • Ploidy: The number of sets of chromosomes in a cell.
  • Haploid: A cell with one set of chromosomes (n).
  • Diploid: A cell with two sets of chromosomes (2n).
  • Karyotype: A display of the chromosome pairs of a cell.
  • Gene: A unit of heredity.
  • Allele: Different versions of a gene.
  • Haploid Number: The number of chromosomes in a haploid cell.
  • Fertilization: Union of sperm and egg to form a zygote.
  • Synapsis: Pairing of homologous chromosomes during meiosis.
  • Bivalent: A pair of homologous chromosomes during meiosis.
  • Sister vs. Non-sister Chromatids: Sister chromatids are identical copies; non-sister chromatids are homologs.
  • Chiasmata: Points of crossover between homologous chromosomes.
  • Crossing Over: Exchange of genetic material between homologous chromosomes.
  • Principle of Independent Assortment: Genes are inherited independently of one another.
  • Genetic Recombination: Creation of new gene combinations.
  • Nondisjunction: Failure of chromosomes to separate properly during cell division.
  • Aneuploidy: Abnormal number of chromosomes (e.g., trisomy, monosomy).
  • Gamete: Mature reproductive cell.
  • Trisomy: Three copies of a chromosome instead of the normal two.
  • Monosomy: One copy of a chromosome instead of the normal two.

DNA and Chromosomes

  • DNA is packaged into structures called chromosomes.

Meiosis vs. Fertilization

  • Meiosis: Process of cell division that reduces the chromosome number by half to produce haploid gametes.
  • Fertilization: Restores diploid condition by combining two haploid gametes.

Sister vs. Non-sister Chromatids

  • Sister chromatids: identical duplicates of a chromosome.
  • Non-sister chromatids: from homologous chromosomes (maternal vs. paternal).

Ploidy Identification

  • Ability to identify organism's ploidy based on karyotype.

Process of Meiosis

  • Overview: Sequences include Meiosis I (reduces ploidy) and Meiosis II (similar to mitosis).
  • DNA Replication: Occurs before Meiosis I.
  • Meiosis I Products: Haploid cells (n) with duplicated chromosomes (result of division).
  • Meiosis II Products: Haploid cells (n) with single chromosomes (similar to mitosis).

Life Cycle of a Diploid Organism

  • Involves processes of meiosis (gametes), fertilization (zygote), and mitosis (growth).

Crossing Over Process

  • Occurs during prophase I with specific terminology like bivalent and chiasmata involved.
  • Result: Increases genetic variation.

Metaphase Plate Alignment

  • Homologous pairs align during metaphase I (unlike mitosis where sister chromatids align).
  • Relates to independent assortment and the genetic diversity it provides.

Fertilization and Genetic Diversity

  • Introduces genetic variation into populations.

Nondisjunction Examples

  • Down Syndrome as case study for nondisjunction in meiosis II.

Parent-Offspring Similarity

  • Asexual reproduction leads to genetically identical offspring; sexual reproduction produces diversity.

Changing Environment Impact

  • Diverse populations fare better in variable conditions.

Case Study: Meiosis and SRY Gene

Terminology Related to Karyotypes and Sex Chromosomes

  • Understand sex chromosome combinations typical for males (XY) and females (XX) in mammals.
  • Analyze karyotypes for evidence of sex and aneuploidy cases.
  • Sex Determination: SRY gene leads to male development; absence leads to female.

Fertilization and Cell Types

  • Draw distinctions among:
    • Haploid cell with one chromatid
    • Haploid cell with duplicated chromatid
    • Diploid cell with one chromatid
    • Diploid cell with duplicated chromatid

Gametes and Sex Determination

  • In mammals, the sperm determines the sex of the offspring.
  • Typical crossover patterns occur mostly at the ends of sex chromosomes.

Genetic Distinctions

  • Conditions leading to XY female or XX male development.

Chapter 14 Learning Objectives

Mendelian Genetics and Chromosomal Theory Terminology

  • Phenotype: Observable traits.
  • Genotype: Genetic makeup.
  • Dominant vs. recessive traits, homozygous vs. heterozygous alleles.
  • Pure-breeding: Individuals with homozygous genotypes.
  • Hybrid: Offspring resulting from a cross between different genotypes.
  • Mendelian Concepts: Monohybrid, reciprocal, and dihybrid crosses, testcrosses, linkage, and different inheritance patterns.

Blending Inheritance vs. Mendelian Patterns

  • Blending inheritance suggests traits mix, but Mendelian patterns reveal discrete inheritance.

Features of Peas as Model Organism

  • Peas had clear traits, were easy to cultivate, and allowed controlled crosses.

Pattern of Trait Inheritance

  • Pure-breeding traits consistently shown in the F1 generation.

Law of Dominance and Segregation

  • Dominance explains which traits appear; segregation explains allele separation during gamete formation.

Punnett Squares and Offspring Probabilities

  • Use squares to predict offspring ratios and infer parent genotypes from offspring traits.

Independent Assortment Principle

  • Genes assort independently during gamete formation, leading to varied offspring combinations.

Sex-Linked Inheritance

  • Traits located on sex chromosomes can show different inheritance patterns.

Gene Linkage and Recombination

  • Linked genes tend to be inherited together unless crossing over occurs.

Multiple Alleles and Dominance Types

  • Traits may show more than two alleles; dominance can be complete, co-dominant, or incomplete.

Environment and Phenotypes

  • External conditions can affect expression of traits.

Quantitative Traits

  • Traits influenced by multiple genes with continuous variation.

Pedigree Analysis

  • Pedigrees illustrate inheritance patterns through generations, particularly for human traits.