LEARNING OBJECTIVES In this section, you will explore the following question: Connection for AP® Courses Proposed independently by Sutton and Boveri in the early 1900s, the Chromosomal Theory of Inheritance states that chromosomes are vehicles of genetic heredity. As we have…
Figure 13.1 Chromosomes are threadlike nuclear structures consisting of DNA and proteins that serve as the repositories for genetic information. The chromosomes depicted here were isolated from a fruit fly’s salivary gland, stained with dye, and visualized under a microscope. Akin to…
Mendel’s Experiments and the Laws of Probability Working with garden pea plants, Mendel found that crosses between parents that differed by one trait produced F1 offspring that all expressed the traits of one parent. Observable traits are referred to as dominant,…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses As was described previously, Mendel proposed that genes are inherited as pairs of alleles that behave in a dominant and recessive pattern. During meiosis, alleles segregate,…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses The characteristics that Mendel evaluated in his pea plants were each expressed as one of two versions, or traits (e.g., green peas versus yellow peas). As…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses Genetics is the science of heredity. Austrian monk Gregor Mendel set the framework for genetics long before chromosomes or genes had been identified, at a time…
Figure 12.1 Experimenting with thousands of garden peas, Mendel uncovered the fundamentals of genetics. (credit: modification of work by Jerry Kirkhart) Chapter Outline 12.1 Mendel’s Experiments and the Laws of Probability 12.2 Characteristics and Traits 12.3 Laws of Inheritance During the 19th century, long before chromosomes…
The Process of Meiosis Sexual reproduction requires that diploid organisms produce haploid cells that can fuse during fertilization to form diploid offspring. As with mitosis, DNA replication occurs prior to meiosis during the S-phase of the cell cycle. Meiosis is…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses Nearly all eukaryotes undergo sexual reproduction. The variation introduced into the reproductive cells (gametes or spores) by meiosis is advantageous for evolution via natural selection. Meiosis…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses As we explored the cell cycle and mitosis in a previous chapter, we learned that cells divide to grow, replace other cells, and reproduce asexually. Without…