3/20- Bell Ringer

*Please make sure you are in the correct seat*

1.If you want to get my attention or answer a question what should you do?

2.What do you need to do in order to win a free day and breakfast/lunch?

3. True or False: If you need to go to the bathroom or have a question about homework you should ask Mr. Arsenie.

Chapter 10: GeneticsMendel’s Contributions

There are at least 250,000 beetle species with a variety of different

characteristics

Over 400 breeds of dog are recognized around the world, each unique for its

personality, habits, and form.

Humans also have multiple characteristics that can vary from

person to person

Even plants have a wide array of unique qualities

How do we understand why each individual living thing looks and

acts the way it does?

Gregor Mendel

o The Father of Genetics

o First person to complete successful work on the study of heredity. (1800’s)

oHe was able to predict how characteristics are transferred from one generation to the next.

#1

Heredity: The passing on of characteristics from parents to

offspring

#2

Genetics: The branch of biology that studies Heredity

Traits: Characteristics that are inherited from generation to

generation

#3

In order to understand the basic mechanisms of heredity, Mendel

needed to do experiments

He used Pea Plants as his test subjects

#4

Why Peas?1. Reproduce sexually

o When the pollen from the male part of the flower comes in contact with the female part Fertilization occurs.

2. Both male and female parts are in the same flowero Pea flowers can self- pollinate

o Sperm cells in pollen fertilize the egg cell in the same flower.

3. Because they self pollinate, pea plants give all of their traits to their offspring

4. If he wanted two different plants to create offspring, Mendel could cross- pollinate them.

Why Peas?

Mendel’s Experimentso Mendel noticed that certain pea plants produced the exact

same form of a trait generation after generation.Self pollinating parent

(First Generation)

Self pollinating offspring(Second Generation)

Plants that produce the exact same form of a trait generation after generation are called True- Breeding

#5

(Third Generation)

o He was curious to see what would happen

when he cross- pollinated two true breeding plants

that had two different forms of a single trait

#6- #7

oThe offspring of true breeding parents that have

different forms of a trait are known as hybrids

The two pea plants being cross pollinated are called the P1- generation (Parental)

The offspring of the P1- generation are called the F1 generation (First Filial)

#8

When looking at the F1 generation, Mendel noticed something strange happening to the hybrid offspring

of the two true breeding parents.

o Mendel noticed that one of the traits was not showing up in the offspring.

o It was as if one of the traits never existed at all!

#9

Mendel was curious as to why this happened so he allowed the F1

generation to self pollinate.

P1 Cross Pollinate

F1

? ? ? ?F2

Self Pollinate

#10

o Each F1 plant that self pollinated produced offspring that had both purple and white flowers.

o The trait that disappeared in the F1 generation reappeared as if from nowhere.

P1 Cross Pollinate

F1

F2

Self Pollinate

¾ Purple¼ White

1. What does pure breeding mean?

2. The offspring of two pure breeding organisms is called a .

3. When Mendel cross-pollinated a pure bred, yellow pea plant with a pure bred, green pea plant, what did the F1 generation look like?

4. What did the F2 generation look like?

Bell Ringer Wed. 3/211st, 3rd, and 5th Period

1. What does pure breeding mean?

2. The offspring of two pure breeding organisms is called a .

3. When Mendel cross-pollinated a pure bred, yellow pea plant with a pure bred, green pea plant, what did the F1 generation look like?

4. What did the F2 generation look like?

Bell Ringer Wed. 3/216th and 8th Period

Mendel’s Conclusions

1. Each organism has two factors that control each of its traits

o These factors are genes and are located on chromosomes

#11-#12

o Genes exist in different forms known as alleles

o For example, in each pea plant, there are two alleles that determine what color the flower will be.

An organisms two alleles are located on different copies of a chromosome- one from mom and one from dad

#13- #14

2. There are some alleles that are dominant and some that are recessiveo Mendel realized this when all of the F1 generation showed

only one of the two possible traits.

o He called the observed trait Dominanto He called the trait that disappeared Recessive

#15- #17

Mendel concluded that the allele for purple flowers wasdominant to the allele for white flowers.

o An organism with a dominant allele for a trait will always express the dominant characteristic.

o An organism with a recessive allele for a trait will exhibit the recessive characteristic only when the dominant allele for that trait is not present.

x

#18- #19

x

o Dominant alleles are represented by a capital letter

o Recessive alleles are represented by the corresponding lower case letter

#20- #23

x

Purple FF

Purple FF

Purple FF

Purple FF

Purple FF

Purple FF

x

Whiteff

Whiteff

White ff

White ff

White ff

White ff

F= Purple Color

f= White Color

Possible Allele Combinations

1. Two Dominant Alleles (FF)

2. Two Recessive Alleles (ff)

3. One Dominant allele and one Recessive allele (Ff)

Purple FF

White ff

Pure- breeding P generation

Hybrid F1 generation

Purple Ff

Purple Ff

Purple Ff

Purple Ff

x

#24

3. Every individual has two alleles for each gene. One is received from the female and one is received from the male.

o When the F1 generation self pollinates, both the male and female gametes have to contribute one allele to the offspring.

P1 Cross Pollinate

F1

F2

Self Pollinate

¾ Purple¼ White

Purple FF

White ff

Purple Ff

Purple Ff

o When fertilization occurs, the male and female gametes randomly pair up.

F f x F f

FFFf Ff

ff

F2 generation offspring

#25

Quick Review Before We Move On

1. What is the difference between a dominant and recessive trait?

2. Where do organisms get their 2 alleles from?

3. What are the three potential allele combinations that an organism can have?

4. If an organism had the alleles Aa, would it show the dominant or recessive trait? WHY?

1. What is the difference between a dominant and recessive trait?

o If an allele for a dominant trait is present, the dominant trait will be seen in the organism.

o If an organism has 2 recessive alleles then the organism will show the recessive trait; however, if the organism has one dominant allele, the recessive trait will be hidden and the dominant trait will be seen.

x

x

2. Where do organisms get their 2 alleles from?

An organisms two alleles are located on different copies of a chromosome- one from mom and one

from dad

3. What are the three potential allele combinations that an organism can have?

1. Two Dominant Alleles (FF)

2. Two Recessive Alleles (ff)

3. One Dominant allele and one Recessive allele (Ff)

4. If an organism had the alleles Aa, would it show the dominant or recessive trait? WHY?

Purple FF

White ff

Pure- breeding P generation

Hybrid F1 generation

Purple Ff

Purple Ff

Purple Ff

Purple Ff

x