Gregor Mendel

Gregor Mendel was a

________who loved

gardening.

In fact, he loved plants so

much that he spent most of his

adult life studying how certain

______ were passed from

“parent” plant to “baby” plant.

Mendel and his peas

Gregor Mendel is most famous for his

scientific study of ___ plants.

Pea plants have ______ observable characteristics.

Each characteristic has ___ possible traits.

Characteristic Possible Traits

1. Plant height -----------------------------Long or short stems

2. Flower position along stem--------------Axial or terminal

3. Pod color-----------------------------------Green or yellow

4. Pod appearance------------------------Inflated or constricted

5. Seed texture-----------------------------Smooth or wrinkled

6. Seed color----------------------------------Yellow or green

7. Flower Color--------------------------------Purple or white

Purebred

By controlling plant ____________

(fertilization), Mendel was able to create

pea plants that were ________ for each

trait.

This is also known as ____ breeding.

True breeding _______ plants always

produce _________ with the same trait.

Purebred

Examples of Pure Breeding:

A purebred Labrador bred with a purebred

Labrador will always produce

________________________________

A plant purebred for purple flowers will always

produce ____________________________.

A plant purebred for white flowers will always

produce offspring with ______ flowers.

What happens if you cross two

purebred plants? Let’s take a look at

flower color….

Mendel called the purebred parents

the _________________.

For each cross (plant “couple”), the P

generation consisted of a

_________purple flower plant and a

_________ white flower plant

Flower color cross

Mendel called the offspring plants the __

generation (1 for 1st , F for filial- son or

daughter)

Plants in the F1 generation are called _______

because their parents have _______ traits.

Mendel discovered that when he crossed a

purebred purple flower plant and a purebred white

flower plant, ALL of the offspring had purple

flowers!

Crossing two purebred plants

In every case of crossing two ________ plants,

one trait “won out” in the ___ generation.

Examples:

Purple flower color “won out” over white flower

colors

Smooth seed texture “won out” over wrinkled seed

texture.

Why do you think this is???

Dominant and Recessive

Traits can be _________ or __________!

Mendel called the trait that appeared in the F1

generation (purple flowers in this case) the

_____________ trait.

Mendel called the trait that did not appear in

the F1 generation (white flowers)

___________ trait.

What do you think happened

when Mendel let plants from

the F1 generation self-pollinate?

Did he end up with purebred

purple flowers?

No!!!

Dominant and Recessive Traits

About ____ of the flowers in the F2 generation

were white!

Even though the ____ generation looked like

purebred purple plants, they carried the trait

for white flowers somewhere inside.

Where was this white flower trait “hidden”??

The traits are hidden in the _____!

A gene is a segment of ___ that codes for a particular _______. The protein results in the _____.

So….. Each _______________ = One ____

For example:

There’s a gene for plant height

There’s a gene for seed color

There’s a gene for flower color

etc...

Alleles

Each alternative (different) form of a gene is

called an ______.

Examples:

The plant height gene has ___ alleles, tall and

short.

The flower color gene has ___ alleles, purple and

white

The seed texture gene has ___ alleles, wrinkled

and smooth.

The gene is

like the

“address.”

The allele is like what or who

you would find at the address.

Mendel came to two conclusions:

1. The Law of _______________: Two factors

(alleles) control each specific characteristic

(gene). These factors (alleles) are separated during

the formation of gametes.

2. The Law of ________________ Assortment:

Factors (alleles) for different characteristics

(genes) are distributed to gametes independently.

This means that the allele for seed texture isn’t

dependent on the allele for plant height, etc.