1. Do you look exactly like either one of your parents
Do you look exactly like either one of your parents? What about your siblings? Why is this & how do you explain it???

2. Summing up Mendel’s Laws
The Key Terms!!

3. What is Genetics?
Study of heredity from generation to generation AND variation of organisms
Heredity – passing of characteristics: parents → offspring
Traits – characteristics received by offspring (Ex: color, size)

4. Somatic Cells vs. Gametes
A quick review of cells…
Somatic Cells vs. Gametes

5. A quick review of reproduction
Sexual reproduction – Sex cells (gametes) from male & female come together
Sperm Egg
Fertilization – fusion of gametes; individual traits passed to fertilized cell (zygote)

6. DNA in sperm & egg cells carry genes on chromosomes
Genes – sections of DNA that code for traits (proteins); come in different forms called alleles
Allele – located on 2 different copies of a chromosome, 1 inherited from mother, 1 from father
Examples: Plant Height – Tall/Short
Plant Color - Purple/White

7. Law of Dominance Dominant allele – masks recessive trait
Recessive allele – trait that can be masked
Example: Can you roll your tongue? Tongue rollers are dominant. Let’s symbolize the tongue rolling trait using a letter code – let’s use “T.”
If dominant is T
Then recessive must be t

8. Genotypes and Phenotypes
Letter codes can be joined together in various combinations…what are they?
TT – tongue rollers
Tt – tongue rollers
tt – non-tongue rollers
Genotype: gene combos
Phenotype: observable character-isitics

9. How do we categorize these combinations???
Homozygous – same 2 alleles → recessive alleles are ALWAYS homozygous
TT, tt
Heterozygous – different alleles Tt

10. Mendel’s Laws Law of Segregation –
Because each organism has 2 alleles → TWO different types gametes can be produced
During fertilization, gametes randomly pair → produce combinations of alleles

11. Mendel’s Laws cont… Law of Independent Assortment
Genes for different traits inherited independently of each other
Genes separate and recombine
This accounts for variation in genotypes/phenotypes!