Introduction to Core Concepts for the Lesson

Lesson 3: Page 2 of 25

Cell Physiology : Introduction to Core Concepts for the Lesson

Karyotype: The chromosomal complement of an individual or a species, including number, form, and size of the chromosomes.

From a genetic standpoint, the defining feature of the sexes is the difference in sex chromosome constitution: females are XX, males are XY. The difference in the female and male karyotypes can be viewed in several ways and each perspective highlights a different mechanism by which basic cellular processes could be affected.

Females are 46,XX; males are 46,XY.
Males have a Y chromosome; females do not.
Females have two X chromosomes; males have only one.

Each of these perspectives is explored in the three sections of this lesson.

Lesson Three Learning Objectives

Upon completing this lesson, the participant will be able to:

Explain how differences in sex chromosome constitution can result in male/female differences in basic cellular processes
State the differences between male and female genomes at the karyotypic and sequence levels
Describe the chromosomal basis of sex determination
Know the gene content of the Y chromosome
Explain why genes on the Y chromosome may be only distantly related to genes on the X chromosome
Articulate that some of the small number of genes on the Y chromosome are expressed throughout the body or in non-gonadal tissues
Describe the Y chromosome effects that are independent of the presence of sex hormones
Articulate that genes on the Y chromosome are protected from mutational loss of function by intrachromosomal recombination
Understand the X-linked patterns of inheritance
Describe the X-chromosome inactivation in all female cells
Recognize that some X-linked genes do produce more gene product in females than in males
Recognize that male and female meioses are prone to different kinds of genetic errors
Explain how maternal and paternal X chromosome genes may function differently