Heredity Unit Notes Quiz #1 Content

(1) Where do our looks come from? REMEMBER: Proteins are the expression of our genetic code. Our DNA stores our genetic code within the nitrogenous bases. The unique sequence of these nitrogenous bases = unique proteins = unique traits We can also call a specific sequence of DNA a “Gene”.

(2) Genotype & Phenotype Genotype = The specific genetic sequence an organism has for a trait. Phenotype = The physical description of what an organism’s trait looks like.

(3) Where do our traits come from? We inherit our traits from our parents. Many animals, like humans, reproduce through “Sexual Reproduction”. Sexual Reproduction involves: The combination of a sperm cell and an egg cell (this is called fertilization). The division and growth of that single cell into trillions of specialized cells (making a multicellular organism). Producing offspring that inherit ½ their genes from a male, and ½ from a female.

So what have we learned/done so far? Trying to breed a super rare gecko, choosing 2 ceckos to breed. Need to understand gecko genetics to do this. Looked at deja and Eric’s gecko breeding results. Looked at PCR charts of gecko breeding results. Came up with some rules we now know about genetics.

(4) Variation in traits “Different Types of Traits” = Different nitrogenous base sequences for a gene. Sexual Reproduction increases genetic variations and diversity in a population. Sex Cells are produced through a special type of cell division called “Meiosis”. In Meiosis, these different types of traits are mixed up and randomly assorted so that each sperm and egg cell is genetically different from every other one.

(5) What happens in meiosis? Meiosis is only used to make more sex cells. The amount of genetic information is cut in ½. (So that when a sperm + egg combine, they will form a full set of DNA.) A special process called “Crossing Over” swaps random genes between chromosomes, increasing genetic variation. Different types of genes (called “Alleles”) separate randomly of one another, also increasing genetic variation.

(6) Types of traits All organisms inherit at least 2 alleles per trait or gene. One allele comes from the mother, one from the father. There are 2 main types of traits: Dominant = Traits which always show up. (Represented by Capital Letters.) Recessive = Traits which only show up when 2 are inherited together. (Represented by Lower Case Letters.)