Gregor Mendel/ Punnet Squares/ Genetics

Hanna

Week 15 : Monday PROBLEM:

• At the end of the year, Ms. Raspberry takes her class to get ice cream. There are 25 kids in the class. 11 Kids get chocolate. 6 Kids get vanilla, 4 kids get strawberry, 3 kids get rocky road, carlos gets lime sherbet.

• Show ratios for the following (#/#, #:#), also show these responses as a %!!! (Divide top # by bottom!)

The whole Class

Ratio of Chocolate lovers to the whole class

Ratio of vanilla lovers to the whole class

Ratio of strawberry lovers to the whole class

Ratio of Rocky Road lovers to the whole class

Ratio of lime sherbet lovers to whole class

Who are you Mr. Gregor Mendel? Born in 1852 in Czech Republic Spent 14 years working in monastery

and teaching Discovered genetics working with

peas in monastery garden Gregor Mendel’s experiments

with pea plants laid the foundations of the science of genetics

Poll Time!Two theories of Genetics

Blending Hypothesis Traits from mother and

traits from father blend together

These traits cannot be separated!

Like coffee mixed with cream

Particulate Hypothesis

Traits from mother and father are kept separate from each other

Some traits are hidden by more powerful traits

Did you choose Particulate theory? Awesome your right!!! Now let’s see how Mendel proved this theory correct!!!

Important Traits Mendel ExaminedCopy into Notebook----I want to see

pictures :0)

Mendel’s Experiment Mendel mated true-breeding father (Yellow peas)

with true-breeding mother (Green peas). True-Breeding- produce offspring identical to

themselves (parent) Each parent has two alleles- traits they can give

to child Parents Genes- DNA determines the possible

alleles (traits) a parent can give to the childY- allele for yellow peay- allele for green pea

Y YFather

y

yMother Father- YY

Mother- yy

Yy Yy

Yy Yy

Yellow Yellow

Yellow Yellow

Punnett Square- Used to test for possible gene combinations (offspring)

P1 Generation

Question Time? Why did all the peas come out yellow? Where

did mothers green pea trait go?• The green pea color (mother’s trait) is recessive to

the yellow pea color (father’s trait) so remains hidden behind yellow pea color. All peas appear yellow.

• Dominant trait- visible trait• Recessive trait- hidden trait

How do we represent a dominant trait?• Dominant trait represented with CAPITAL letter

How do we represent a recessive trait?• Recessive trait represented with lower case letter

Punnett Square Practice Time!!! Homozygous alleles- Aka: True-

breeding• YY and yy

Heterozygous alleles- 2 different alleles• Yy

Cross Heterozygous Yellow pea (Yy) with a Heterozygous Yellow Pea (Yy)

Y- yellow peay- green pea

F1 Generation

Phenotype- Physical trait (yellow peas, green peas)Genotype- Genes/Alleles (YY, Yy, yy)

More Punnett Square Practice

Pod Color: Yellow vs. Green

Plant Height: Tall vs. Short

Pod Shape: Smooth vs. Constricted

Flower Color: Purple vs. White