1. Genes and their role

4. Compare the number of chromosome in body cells vs sex cells.

5. Identify the role of cell division in reproduction. 

6. Identify the role of X and Y chromosomes in determining gender

Henry the Eighth married six women, two of whom he divorced and two he executed -- all in the attempt to have a male heir, a son to continue his line. His first wife had only a daughter to survive, with 5 stillbirths. Anne Boleyn had a daughter, who later became Elizabeth 1.  Henry had an heir, Edward VI, with his third wife, Jane Seymour, but Edward died at the age of 15, possibly from tuberculosis. His next three wives did not produce children. [Divorced=beheaded=died=divorced=beheaded=survived.]

Henry blamed the lack of male heirs on his wives, and produced reasons to have them removed as queen.  What does science say about this?

The determination of genetic sex happens at the moment of fertilisation (conception). 

Human body cells have 46 chromosomes in 23 pairs, with one of each pair coming from the mother, and the other of each pair coming from the father. Each one in pairs 1-22 matches its partner in size, shape and characteristics. The 23rd pair, called the sex chromosomes because they help determine whether a person will develop male or female sex characteristics, come in two different types, called the X-chromosome and the Y-chromosome. 

A female is typically XX, a male is typically XY. If a baby inherits two X chromosomes, one from each parent, it will be genetically female. If a baby inherits an X from the mother and a Y from the father, it will be genetically male. 

The SRY gene, the gene for maleness, is found only on the Y-chromosome and provides instructions for making a protein called the Sex-determining Region Y protein. This protein starts processes that cause a foetus to develop male gonads (testes) and prevent the development of female reproductive structures (uterus and fallopian tubes).