Genetics – Learning Outcomes Understand inheritable and non-inheritable characteristics. Know that inheritable characteristics are controlled by genes. HL: Recall where genes are located. HL: Recall the number of pairs of chromosomes in humans. HL: Recall the location of chromosomes. HL: Recall the composition of chromosomes.

Understand Inheritable Characteristics Some characteristics of people are controlled by genetics. These are called inheritable characteristics. Some examples are hair colour, eye colour, hair line, toe length, and knuckle hair. by LeuschteLampe – public domain

Understand Non-Inheritable Characteristics Some characteristics are not inherited – they are picked up over the course of a life. These are called non-inheritable characteristics. Some examples are learned skills, behaviour, food preferences, and sport preferences.

Inheritable or Non-Inheritable? Characteristic Inheritable Non-Inheritable Ability to speak French Ability to roll your tongue Hair colour How tall you are Eye colour How good you are at maths Whether you will get heart disease Whether you like cucumber How fast you can run

What Controls Characteristics? The study of inherited characteristics is called genetics, because they are controlled by genes. Genes are passed from parents to children when reproduction occurs. Everyone gets two copies of each gene – one from their mother and one from their father. Usually, only one of these copies will affect you – this is called a dominant gene. The copy of the gene that does not affect you is called the recessive gene.

What Controls Characteristics? e.g. Brown hair is dominant, while blond hair is recessive. Mother’s Gene Father’s Gene Your hair colour Brown Blond

What Controls Characteristics? This does not mean that two brown-haired parents can only have brown-haired children. Each parent has two genes also, but only passes one to their child. If they both pass a blond gene to their child, the child can be blond, even if both parents have brown hair. Mother Passes Brown Blond Father Passes

HL: Locate Chromosomes Genes are located on chromosomes. Each cell in a given human contains the same 23 pairs of chromosomes in the nucleus. Sperm also have a tail which is used for swimming. by Earthdirt – CC-BY-SA-3.0 by Henry Gray – public domain