Transcript Section 11-1

The Work of
Gregor Mendel
Transmission of characteristics
parents to offspring
from _______________________is
heredity
called ___________________.
SCIENCE that studies how
The _________
_____
those characteristics are
passed on from one
_________
generation to the next is called
___________________
Genetics
Father of Genetics
The __________________
is
_________________,
Gregor Mendel
a monk whose study
_________ of
genetic traits was the
beginning of our
understanding
_________________
about
how genes work
_____________________.
Mendel designed
experiments using
____________
Pea plants in the
__________
monastery garden
MALE part of flower makes
_______
Pollen
___________
(sperm)
FEMALE
__________ part of flower makes
_______
cells
egg
In pea plants, the pollen normally
joins with an egg from the
same plant (=_______________
ONE parent
_______
) so seeds have
Self pollinating
“_________________”
MENDEL’S PEA EXPERIMENTS
Mendel started his experiments with
peas that were
true breeding
_________________
= if allowed to
self pollinate
_________________
they would produce
offspring identical
____________________
to themselves.
MENDEL’S PEA EXPERIMENTS
pollen
Mendel removed
____________________
pollen
making parts andadded
____________
from another
_______ plant.
This allowed him to
_____________
cross-breed plants
with ______________
different
characteristics and
study the results
________
specific characteristic
A _____________________
is
trait
called a ____________
Mendel studied
______________
in
7 traits
peas.
MENDEL’S EXPERIMENTS
P1 generation
____
(_________)
parental
F1 generation
____
filial
(______=
offspring)
F2 generation
___
Principles of Dominance
Section 11-1
P Generation
Tall
Short
F1 Generation
Tall
Tall
F2 Generation
Tall
Tall
Tall
Short
Principles of Dominance
Section 11-1
P Generation
Tall
Short
F1 Generation
Tall
Tall
F2 Generation
Tall
Tall
Tall
Short
Principles of Dominance
Section 11-1
P Generation
Tall
Short
F1 Generation
Tall
Tall
F2 Generation
Tall
Tall
Tall
Short
crossed PURE PLANTS
When Mendel ______________
with 2 ______________
traits:
contrasting
(EX: Tall crossed with short)
He always found same pattern:
ONE trait ____________
showed
1. ONLY ______
F1 generation BUT . . .
in the ____
Missing
returned
2. ___________
trait ____________
in
F2 generation
the ____
3:1
in a _________
ratio
PATTERNS ARE THE KEY
Mendel decided that there
must be a
pair of FACTORS
__________________
that
control
________each
trait and that
one factor must be able to
__________
HIDE
_______
the other.
We now know that Mendel’s
factors are genes carried on
________________
the pair of________________
homologous
_________________
chromosomes
DIFFERENT
________
gene
_______ for a
CHOICES
trait are called
___________.
ALLELES
DOMINANT
__________________
= An
allele that ________
HIDES the
presence of another allele
RECESSIVE
__________________
= An
allele
is
hidden
by
that __________________
the
presence of another allele
Why did the recessive trait
disappear in the F1 generation and
reappear in the F2?
The pattern corresponds
movement of
to the ____________
chromosomes during
______________
MEIOSIS
____________________
WHAT DOES MEIOSIS HAVE
TO DO WITH IT?
REMEMBER
HOMOLOGOUS
_____________
chromosomes
SEPARATE
________________
during
ANAPHASE I
= _________________
SEGREGATION
____
F1 offspring __________
received an allele for
tallness from their _______
TALL parent and an
allele for shortness from their ________
SHORT
parent.
The F1 plants ALL ___________
LOOK TALL
carryingan
but are ___________
allele for _____________
shortness
EXPLAINING the F1 CROSS
SEGREGATION
LAW OF ___________________
alleles are separated
when the F1 plants
______________
made gametes
When these gametes recombined to make the
recessive
F2 generation, the _____________
trait
_______________
reappears in ¼ of the offspring