What is a Gene Gene Humans have approximately

What is a Gene? • Gene = ___________________________________ • Humans have approximately ______ genes • We have _____ copies of each gene (one on each chromosome we inherited from our ______). • Each gene has different forms. . . • Allele - ______________________________________

Examples of Genes and Alleles in Pea Plants • Gene – Seed Shape Alleles: _____________ • Gene – seed color Alleles: _____________ • Gene – flower color Alleles: _____________

Chromosomes occur in pairs because offspring inherit one from each parent • *We have 46 Chromosomes (23 pairs of chromosomes) • Chromosomes are made of genes – Circle one gene. – What are the 2 alleles for that gene? *Each chromosome is made up of ____ that contains hundreds to thousands of _____. *HIERARCHY:

Dominant vs. Recessive • NOT ALLELES ARE EXPRESSED • Some alleles are dominant, while others are recessive Description More Info Dominant Alleles *These usually code for a protein so they are the “normal” form of a gene. Recessive Alleles *These usually code for a different protein, or deactivate the “normal” protein. Examples

What happens when we change our DNA? • Mutations: __________________________________ • Gene Mutations: _______________________________ Types: _________________ • Chromosomal Mutations: ____________________________ Types: _________________ THESE CHANGES CAN AFFECT _____ MADE AND THEREFORE AFFECT YOUR _______.

TYPES OF CHROMOSOMES • Autosomes: ______________ • Sex Chromosomes: ___________ • Karyotype: __________________________________ • Where do you look To determine the sex of this human? • How do you know If it is normal or abnormal?

Karyotype Notation:

Significance of Mutations What Causes Mutations? §There are two ways in which DNA can become mutated: 1. MOST ARE _______ 1. Mutations can be _____. §Parent to child • Eye color 2. Mutations can be _____. • Birth marks §Environmental damage 2. SOME are _______ §Mistakes when DNA is • Sickle Cell Anemia copied §________failu • Down Syndrome re of chromosomes to 3. SOME are _______ separate properly during • Sickle Cell Anemia to Malaria Meiosis. • Immunity to HIV §What phase normally causes this?

PRACTICE WITH KARYOTYPES

MORE PRACTICE. . .