Notes

Chapter 6 Section 4
VOCABULARY:
1. Gene- a piece of DNA that provides a cell a set of instructions make a certain protein.
2. Locus- a specific position on a pair of homologous chromosomes. (Each gene has one of these)
3. Allele- any alternative form of a gene occurring at a specific locus on a chromosome. (Each parent donates one for every gene)
OPPOSITE 4. Homozygous- (term) two alleles that are at the same locus and are the SAME. [Alleles are identical ]
OF EACHOTHER 5. Heterozygous- (term) two alleles that are at the same locus and are DIFFERENT. [Alleles are different ]
6. Genome- All of an organisms genetic material
7. Genotype- refers to the genetic makeup of specific set of genes
8. Phenotype- the PHYSICAL characteristics (traits) of an individual organism. PHYSICAL expression of a trait
9. Dominant- (Allele) is the allele that is expressed when two different alleles or two dominant alleles are present.
10. Recessive- (Allele) is the allele that is expressed only earn two copies are present.

NOTES:
Genes:
- The same gene can have many versions
- Alternative version of a gene occurring at a specific locus on a chromosome is a Allele
- Each parent donates one allele for every gene
- Each gene has a locus (a specific position on a pair of homologous chromosomes)
- (Genes) Influence the development of traits.
All organisms genetic material is called the GENOME

GENOTYPE vrs. PHENOTYPE:
Genotype: is the genetic makeup, UNDERLYING genetics of an organism
Example: Homozygous Dominant, Homozygous Recessive, and Heterozygous
- Homozygous Alleles are the SAME
- Heterozygous Alleles are DIFFERENT
***BOTH Homozygous Dominant and Heterozygous GENOTYPES yield Dominate phenotypes***
Phenotype: is the PHYSICAL expression of a trait, OBSERVABLE traits of an organism
- Is effected by both the Environment AND by alleles
Example: What you see --------> Remember Photograph-Phenotype

ALLELES representation:
-Dominant Allele-
-expressed as a phenotype when at least one allele is dominant
:REPRESENTED: Uppercase letter (Q)
-Recessive Allele-
-expressed as a phenotype when TWO copies are present that are recessive
:REPRESENTED: lowercase letter (q)

-Homozygous Dominant- 2 Capital Letters (Example: AA)
-Homozygous Recessive- 2 lower case letters (Example: aa)
-Heterozygous- 1 Upper case and 1 lower case letter (Example: Aa)


------------------NOTE--------------------------
When representing alleles use the dominant traits first letter when writing.
You do NOT use the recessive traits letter. You also do NOT just pick a random
letter to represent what you are talking about