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.