What are the chances that:1) a dice cube will fall on “six”

twice in a row? 2) a mother with Hh will pass on

an h to her child?3) a father with Hh will pass on

an H to his child?4) both 2 and 3 will occur?

Show your work!

Vocabulary:

Draw the ARROWS of the terms to the examples, correctly!

B. Try it with coins!

Copy the following data table:

H T

Tally (20 throws):

HH TTHT TH

Tally (50 throws):

One coin:

Two Coins:

Throw the coins and count!

D. In Conclusion:

1) In real life we don’t necessarily get the exact predicted numbers.

2) In order to get closer in an experiment to the predicted ‘true’ probability, we need to……?

Kreiselman Period 2:

Some would say – Mendel was not the first to discover genetics. What was observed before him?

What was Mendel’s contribution to the understanding to the mechanism of inheritance?

Sweet Peas

Gregor Mendel, Austria, Mid 1800’s

Mendel’s Experiment

Decisions Mendel made when designing his experiments:

1. Control the pollination. 2. Start with pure-bred plants.(many generations of self-

pollination)3. Focus on traits that show only

two clear, ‘either or’, phenotypes.

Mendel’s 1st ExperimentsPicked pea plants, that were self-pollinating for several generations. Pure-bred plants.

male

female

X“Pure tall”

“Pure short”

Offspring plants: Height?

male

female

Pure

Parental (P1)

generation

Step one: Assured cross – pollination by removing one

gender each time.

X

Parental (P1)

generation

Purple - flowered

White - flowered

X

Offspring (F1)

generationWhy?

XF1Hybrid offspring

Why?

F2

Phenotypes and their ratios:Mendel’s counts of various traits:

Peas: Wrinkled 1850Round 5474

Height:Short 277 Tall 787

Flower: Purple 705 White 224

Peas: Green 1850 Yellow 6022

Can you find a pattern?

Peas: Round: Wrinkled

Height: Tall:Short

Flower: Purple:White

Peas: Yellow:Green

2.96:1

2.84:1

3.15:1

3.01:1

Ratios:

No Matter which trait – always found a ratio of ~3:1 (same as 75:25%) between 2 phenotypes.

Mendel’s explanation:1.Each plant inherits pairs of

“factors” (genes), one from each parent.

2. There are two variants (alleles) for the gene, one variant is dominant and one is recessive.

3. Two forms of each gene are randomly separated (segregated) during the formation of reproductive cells.

To make it more methodic… Mendel gave them letters:

P – dominant allele (purple)p – recessive allele (white)

Pure bred (Parent generation): PP , pp

Hybrids (F1 generation): Pp

Pp PpGenotypes

Segregation(in meiosis)

P p P p gametes(sex cells)

PP pPPp ppPossible genotypes of offspring

Ratio: _1:2:1___

Genotypes Phenotypes

Ratio: __3:1___

Punnet squares

P p

P

p

P P Pp

pppP

Purple Purple

Purple White

Pp

Pp

P p

P

p

P p P p3.1.

2.

For each number in the punnet square – find the corresponding part in the ‘circle’ diagram.What do these parts represent?

First Punnet Square exercise:Monohybrid cross of a bear

Trait Dominant Allele

Recessive Allele

Pod ShapePod ColorFlower PositionPlant Height

Smooth (N)

Green (G)

Axial (A)

Tall (T)

Constricted(n)

Yellow (g)

Terminal (a)

Short (t)

1) What must be the genotype (AA, Aa or aa) of an individual with a recessive phenotype?

2) The relationship between genotype and phenotype is compared to thought and action of a person. Which is the action and which is the thought? Explain.

Use chart of traits to write:1) Phenotypes of the genotypes:Gg, gg, nn, Nn, 2) All possible Genotypes of the phenotypes: Smooth Pod, Short plant, 3) Examples of: Homozygote recessive, homozygote dominant, heterozygote for plant height.

It is relatively common that two brown-eyed parents have a blue-eyed child, but it is rare that two blue-eyed parents have a brown eyed- child. Why? Explain, using the terms: homozygote, heterozygote, dominant recessive.

Monohybrid crosses:• Write the information given about the parents.• Write the ratios and percentages, include the genotypes and phenotypes in your answer.• For questions 5-10: write in complete sentences!

Divide your page to four parts. On the left write the following pairs of terms, and on the right side draw the relationships between these terms.

1) Gene-allele2) Genotype-phenotype3) Recessive-Dominant4) Homozygous-Heterozygous

Pigments of the skin (and eyes) are in fact proteins that absorb light. A gene contains information to make a protein.

If allele 1 is an active gene, and the allele 2 is inactive. Which allele is dominant, 1 or 2? Explain.

1.What is the chance that a flipped coin will fall, on ‘heads’?

2. What is the chance that this will happen twice in a row?

Explain.

(Guidance: The chance to have something happen twice is smaller than only once) .

MeiosisA

a

b B

What is the chance (in %) that a selected egg will have a Blue-a? a Navy-A? Why?

?A

A, B = genes

MeiosisAa

b B

What is the chance (in %) that a selected egg will have an A or an a? Why?

A, B = genes

2 over 4 = 50%

MeiosisA

a

b B

What is the chance (in %) that a selected egg will have both a blue A and an orange b?

?A

A, B = genes

½ x ½ = ¼ = 25%

1) What did you learn from the flower dissection yesterday?

2) What questions do you have regarding the plant’s way of life?

Often Phenotypes “skip a generation”. 1) Give examples (if you can) from your family.2) Why does this happen?Use – heterozygote, allele, dominant, recessive, genotype

1) What are the two traits?2) Which phenotypes are probably carried by dominant alleles? 3) What is produced by the gene responsible for the plant’s color?

Corn Seedlings:

Sweat Peas

Mendel’s 3rd law of independent assortment: Each gene is segregated regardless of what happens to other genes.

A

B

C

Considering their locations on the 2 chromosomes, which two genes follow this rule? A-B, B-C, A-C? Explain.

The gel includes a father and four children. Which must be the father?Explain.