1. Do Now Put modeling meiosis in bin.
2. Explain difference between heterozygous and homozygous.
3. Explain difference between dominant and recessive.
4. Explain difference between phenotype and genotype.

2. Portion of DNA (nitrogen bases) that codes for a trait
Review: Gene
Portion of DNA (nitrogen bases) that codes for a trait

3. Two different forms of a gene: Dominant and Recessive
Review: Allele
Two different forms of a gene: Dominant and Recessive

4. Key: D = no dimples and d = dimples AND H = Unibrow and h = Two eyebrows
Identify the Genes:
Identify the Alleles:
Alleles
Phenotype
Genotype dd
HhDd DD
Ddhh

5. Tool used to predict the genotypes and phenotypes of offspring
Punnett Square
Tool used to predict the genotypes and phenotypes of offspring

6. What is Monohybrid Cross?
Punnett square using
only one trait.

7. Monohybrid Cross and Mendel
If purple is dominant and white is recessive, cross a purebred (homozygous dominant) purple flower with a white flower.
Which allele is dominant?
Purple X PP pp

8. PP x pp p p P Pp Pp P Pp Pp

10. 1st generation Self Pollinates
Pp x Pp P p P PP Pp p Pp pp

12. What do Punnett Squares represent?
MEIOSIS
Possible eggs from Mom A
Possible sperm from Dad a
Each square represents the possible combinations of alleles inherited by offspring
MEIOSIS A A A A a A a A a a a a

13. How to do a Punnett square problem
1. List the symbols & alleles
T = Tall
t = Short

14. How to do a Punnett square problem
2. List the Parental Cross
T = Tall
t = Short
Tt x Tt

15. How to do a Punnett square problem
3. Do the Punnett square
T = Tall
t = Short T t
Tt x Tt T T T T t t T t t t

16. How to do a Punnett square problem
4. List the genotypic ratio
T = Tall
t = Short T t
Tt x Tt T T T T t
G = 1TT : 2Tt : 1tt t T t t t

17. How to do a Punnett square problem
5. List the phenotypic ratio
T = Tall
t = Short T t
Tt x Tt T T T T t
G = 1TT : 2Tt : 1tt t T t t t
P = 3 Tall:1 Short

18. How to do a Punnett square problem
6. Answer any questions associated with the problem. T t
T = Tall
t = Short T T T T t
Tt x Tt
G = 1:2:1 t T t t t
P = 3:1

19. Example #1
A male that is heterozygous for purple hair is crossed with a orange haired woman. What chance to they have in producing a purple haired child? Orange haired child? (Purple hair = P and orange hair = p)

20. Example #2
If a man that is a purebred with big ears marries a heterozygous woman for this trait, what is the chance that their first child might express the dominant trait? Big ears = B and Little ears = b

21. Example #3
A couple is heterozygous for the gene for big nose. They are about to have a child and hope that it has a small nose. Do they have a chance? How much of a chance? B = Big nose and b = small nose