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 ShapeAlleles: _____________

_____________• Gene – seed colorAlleles: _____________

_____________• Gene – flower colorAlleles: _____________

_____________

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 ALL ALLELES ARE EXPRESSED• Some alleles are dominant, while others are

recessive

Description More Info Examples

DominantAlleles

*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.

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 lookTo determine the

sex of this human?

• How do you know If it is normal or abnormal?

Karyotype Notation:

Significance of Mutations

1. MOST ARE _____________• Eye color• Birth marks

2. SOME are _____________• Sickle Cell Anemia• Down Syndrome

3. SOME are _____________• Sickle Cell Anemia to Malaria• Immunity to HIV

What Causes Mutations?

There are two ways in which DNA can become mutated:

1. Mutations can be _________. Parent to child

2. Mutations can be _________. Environmental damage Mistakes when DNA is

copied ________________failur

e of chromosomes to separate properly during Meiosis.

What phase normally causes this?

PRACTICE WITH KARYOTYPES

MORE PRACTICE . . .