1. Bell Ringer
What does NOT happen between Meiosis I and Meiosis II that reduces the number of chromosomes?
When animals reproduce, which process replicates their chromosomes?
In one sentence, describe what happens during Meiosis I.

2. Mendelian Genetics and Punnett Squares
Biology
February 13, 2014

3. Gregor Mendel Austrian monk who studied garden peas.
Noticed certain patterns as he observed each generation.
Began experimenting by crossbreeding.
crossbreeding: mating two organisms to produce offspring

4. Mendel’s Traits Mendel studied seven different traits:
height (tall/short)
flower color (purple/white)
flower position (axial/terminal)
seed color (yellow/green)
seed shape (round/wrinkled)
pod color (green/yellow)
pod shape (inflated/constricted)

5. HUMAN TRAIT INVENTORY

6. Describe the two pea plants.
Height:
Flower Color:
Flower Position:
: Dwarf
Height:
Flower Color:
Flower Position:
: Tall
: Purple
: White
: Axial
: Terminal

7. Gregor Mendel’s Experiments
1) chose a trait to examine
2) cross-pollinated members of the parent (P) generation
3) counted the results in the first filial (F1) generation
4) cross-pollinated members of the F1 generation
5) counted the results in the second filial (F2) generation

8. Mendel’s Experiments P Generation: Purebred Tall x Purebred Short
Result (F1 Generation): All Tall
F1 Generation: Tall x Tall
Result: (F2 Generation) 75% Tall, 25% Short

9. Gregor Mendel’s Conclusions
traits are inherited from one’s parents.
traits follow specific laws as they are passed, resulting in predictable ratios
ex. heterozygous tall x heterozygous tall
**** T t
75% Tall
25% Short T TT Tt t Tt tt

10. Genetics Vocabulary : a piece of DNA that codes for a trait gene:
ex. height
: a piece of DNA that codes for a trait

11. Genetics Vocabulary allele: : different forms of the same gene
each individual has two alleles for each trait
one allele comes from each parent
ex. T or t
dominant allele:
recessive allele:
: different forms of the same gene
: always expressed when present
: expressed when no dominant is present

12. Genetics Vocabulary : combination of alleles for a trait genotype:
homozygous:
ex. TT or tt
heterozygous:
ex. Tt
phenotype:
ex. tall or short
: combination of alleles for a trait
: both alleles are the same
: both alleles are different
: physical characteristic of an organism

13. Trait: pea plant height
Genotype vs Phenotype
Trait: pea plant height
Genotype
Phenotype
Example TT
homozygous tall Tt
heterozygous tall tt
homozygous dwarf

14. Review
Directions: Identify the following as a trait/gene, an allele, a genotype, or a phenotype. Y Ww
Flower Color
Yellow Seeds TT
Flower Position t
Dwarf
Plant Height
Purple Flowers
allele
trait/gene
genotype
allele
trait/gene
phenotype
phenotype
trait/gene
genotype
phenotype

15. PRACTICE!

16. Mendel’s Laws 1. The Law of Segregation:
the two alleles that make up the genotype separate during meiosis so that each gamete only has one copy T \ T TT \ T \ t Tt \

17. Mendel’s Laws 2. The Law of independent assortment:
alleles of different genes assort independently TW \
TtWw Tw \ tW \ tw \

18. Mendel’s Laws 3. The Law of Dominance:
if a dominant allele is present in the genotype, it will be expressed in the phenotype
Tall (TT)
Tall (Tt)
Dwarf (tt)

19. What type of car is this?
GAS + ELECTRIC
Hybrid =
MIXED FROM 2 PARTS

20. Monohybrid Cross
ONE
MIXED
MATING
1 Pair of Traits
Mom + Dad

21. Possible Offspring inside boxes
Punnett Square:
a diagram used to predict the outcome of a particular genetic cross T t
Father’s Genotype TT Tt T
Mother’s
Genotype T
Possible Offspring inside boxes

22. Multiplication Table 1 2 3

23. Multiplication Table 1 2 3 1 2 3 4 6 9

24. Possible Offspring inside boxes
Punnett Square:
a diagram used to predict the outcome of a particular genetic cross T t
Father’s Genotype TT Tt T
Mother’s
Genotype T
Possible Offspring inside boxes

25. tall (T) is dominant to short (t)
Genotype
50% Tt
50% tt
1:1
Phenotype
50% tall
50% short
1:1
heterozygous tall t Tt tt
hetero tall
homo short
homozygous short t Tt tt
hetero tall
homo short

26. tall (T) is dominant to short (t)
Genotype
25% TT
50% Tt
25% tt
1:2:1
Phenotype
75% tall
25% short
3:1
heterozygous tall T TT Tt
homo tall
hetero tall
heterozygous tall
NOTE: All monohybrid Crosses of heterozygous of parents produce these ratios. t Tt tt
hetero tall
homo short

27. purple flowers (W) are dominant to white (w)
Genotype
100% Ww
Phenotype
100% purple
homozygous purple w Ww Ww
hetero pur
hetero pur
homozygous white w Ww Ww
hetero pur
hetero pur

28. purple flowers (W) are dominant to white (w)
Genotype
50% Ww
50% ww
1:1
Phenotype
50% purple
50% white
1:1
heterozygous purple w Ww ww
hetero pur
homo white
homozygous white w Ww ww
hetero pur
homo white

29. Review What are genes? What’s a genome?
How many copies of each gene do we each inherit?
What is probability?
Organisms that have two identical alleles for a particular trait or what?
What do letters inside a Punnett square represent?
If a tree is homozygous recessive for height (T, t), how would its alleles be represented?
When Mendel crossed a tall plant with a short plant, the F1 plants inherited what?

30. Review
Which principle states that during gamete formation, genes for different traits separate without influencing each other’s inheritance?
If you flip a coin 67 times, what’s the probability that it will come up heads?
If two people that cross their eyes (E) marry and have a child that cannot cross their eyes (e), what are the genotypes of the parents? Why?
Who or what does Gregor Mendel’s principles of genetics apply to?

31. Remember, Ch. 6-3,4,5,6 Vocabulary Quiz Tomorrow!
Independent Practice
Complete Monohybrid Cross worksheet (Will be checked during Bell Ringer tomorrow. NO LATE WORK ACCEPTED)
Review Vocabulary (All words are on Quizlet)
Remember, Ch. 6-3,4,5,6 Vocabulary Quiz Tomorrow!