1. Genes
3.1

2. Essential Idea: Every living organism inherits a blueprint for life from its parents.
3.1
Genes
Understandings:
A gene is a heritable factor that consists of a length of DNA and influences a specific characteristic
A gene occupies a specific position on a chromosome
The various specific forms of a gene are alleles
Alleles differ from each other by one or only a few bases
New alleles are formed by mutation
The genome is the whole of the genetic information of an organism
The entire base sequence of human genes was sequenced in the Human Genome Project
Applications:
The cause of sickle cell anemia, including a base substitution mutation, a change to the base sequence of mRNA transcribed from it and a change to the sequence of a polypeptide in hemoglobin
Compare the number of genes in humans with other species
Skill:
Use a database to determine differences in the base sequence of a gene in two species

3. Found at a particular locus on a chromosome.
Gene – a heritable factor that consists of a length on DNA and influences a specific characteristic
Found at a particular locus on a chromosome.

4. Number of genes in various species

5. Alleles – versions of a gene (variation in one – a few bases) that code for different expressions of genes

6. Mutations
Change in the DNA
Responsible for creating different alleles
Where is the mutation?
What would be the resulting mRNA if these sequences are transcribed?

7. What effect does this have on the amino acid sequence?

8. What effect would this change have on the functioning of this polypeptide and why?

9. Types of Mutations
Base substitutions – one base in substituted for another
Frameshift mutations – additions or deletions
Changes the reading frame for the rest of the polypeptide

10. Cystic Fibrosis

11. HIV and the LRP5 gene
Original allele produces receptor that HIV uses to infect cells
Mutation = no receptor = HIV cannot infect cells

12. Lactose intolerance
Originally humans did not produce lactase much past infancy
As cultures became more agriculture dependent, more people continued to produce lactase into adulthood

13. Sickle cell disease
6th triplpet in hemoglobin protein DNA changed from GAG to GTG
Results in 6th amino acid changing from glutamic acid to valine

15. Advantages of sickle cell allele
Malaria resistance – Plasmodium parasites cannot infect sickle red blood cells

16. Genome
All of the DNA in a cell of an organism
Human Genome Project – base sequencing of all human genes
Started in 1990, finished in 2003