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 (trait)
Found at a particular locus on a chromosome
Traits may also be influenced by multiple genes

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

5. Mutations
Change in the DNA
Responsible for creating different alleles
Discuss as a table:
Where is the mutation?
What would be the resulting mRNA if these sequences are transcribed?

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

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

8. Gene mutations can be beneficial, detrimental or neutral.
Beneficial mutations change the gene sequence to create new variations of a trait that are advantageous
Detrimental mutations change the gene sequence in a way that stops the normal function of a trait
Neutral mutations have no effect on the functioning of the specific feature

9. Discuss as a table:
Discuss the impact of beneficial, detrimental, and neutral mutations on natural selection an evolution.

10. 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

11. Types of point mutations

12. Cystic Fibrosis

13. HIV and the LRP5 gene
Original LRP5 allele produces receptor on any types of cells that HIV uses to infect cells
Mutation = no receptor = HIV cannot infect cells

14. 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

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

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

19. Genome
Genome is the total genetic information of a cell, organism or organelle
This includes all genes all well as non-coding DNA sequences
The human genome consists of:
46 chromosomes
3 billion base pairs
21,000 genes

20. Human Genome Project – base sequencing of all human genes
Started in 1990, finished in 2003
Approximately 23,000 genes
Led to the discovery of “junk DNA” – not really junk, just doesn’t code for proteins

21. Number of genes in various species