Download GREGOR MENDEL: The Father of Genetics

SBI3C Genetics
Name: _______________________
Date: ________________________
GREGOR MENDEL: The Father of Genetics
Genetics is the scientific study of ___________________________.
Heredity is the passing of ______________________ from parent to offspring.
The first major experiments of heredity were done by an Austrian monk
named Gregor Mendel (1822-1884). He is known as the __________________.
Gregor Mendel wondered why when some plants were bred, the offspring did
NOT become “blended” versions of their parents. So he investigated through
experiments on ________________. For 7 years, Mendel grew and tested 20,000
pea plants!
Why Peas?
 Peas _________________ and didn’t take up much space.
 Peas show a variety of different _________________: pea colour, flower
colour, height, seed colour, pod shape, seed shape, flower position.
 Peas usually reproduce by ________________________: the flower is able to
fertilize itself. This always produces offspring with the same traits as the
parent cell, called a PUREBRED.
 Peas can also _____________________: producing offspring that may be different or the same
as the parent plant, called a HYBRID.
Mendel’s Work:
He cross-pollinated pea plants
with ___________ flowers
(parent 1) with pea plants with
_____________ flowers (parent
2). And saw that in the first
generation (F1), ALL the peas had
____________ flowers (the white
colour disappeared!)
Then he took the white flowers
and created a second generation
(F2) by letting the hybrid plants
self-fertilize, and found that the
white colour reappeared! But this
time there was a clear _________
of 3 purple plants to 1 white
plant. (3 purple : 1white)
What Mendel discovered - Mendel's Laws of Inheritance

Each plant must have two factors for each physical trait, one from each parent.
Traits are:

Factors are:
Some genes, like “purple” will always appear, even if ONE factor is present
Visible forms:

Other genes, such as “white flowers” can be masked or hidden by other genes
Masked forms:
1. Law of Segregation
For each trait an individual carries, there are _____________. Each parent passes on one of its two
alleles to each offspring. The chances of which allele is passed on is ____________.
 If an offspring inherits two dominant characteristics, or one dominant and one recessive, it will
show the _________________________.
 If the offspring inherits two recessive characteristics it will then show the _________________.
Genotype:
Example: PP, Pp, pp
Homozygous:
Phenotype:
Example: PP or Pp will give the phenotype
“purple”; pp will give the phenotype “white”
Example: PP or pp
Heterozygous:
Example: Pp
2. Law of Independent Assortment
The inheritance of alleles for one trait _______ ______ _________ the
inheritance of alleles for a different trait.
Summary
Scientists have confirmed Mendel's laws and agree that they apply to
many plant and animal traits. Mendel's conclusions became known as
Mendel's Laws of Inheritance.
 Today biologists call the units of heredity:___________.
 Genes are located on _______________.
 The separate forms of a gene are called ____________. For
example, a gene controls the height of a pea plant. One allele of that gene produces short
plants and the other allele produces tall plants.