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The Work of Gregor Mendel
Chapter 11-1
Transmission of characteristics from
parents to offspring
_______________________is
called
___________________.
heredity
how those
SCIENCE that studies _____
The _________
characteristics are _________
passed on from one
generation to the next is called
Genetics
___________________
The __________________
Father of Genetics is
_________________,
Gregor Mendel
study
a monk whose _________
of
genetic traits was the beginning of
our _________________
about
understanding
_____________________.
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
_______
egg cells
In pea plants, the pollen normally joins
with an egg from the _______
same plant
(=_______________
Self pollinating ) so seeds have
“_________________”
ONE parent
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
removed pollen
Mendel ____________________
making parts and ____________
added pollen
from _______
another plant.
This allowed him to
_____________
cross-breed plants
with ______________
different
characteristics and
study the results
________
specific characteristic is
A _____________________
trait
called a ____________
Mendel ______________
studied 7 traits in peas.
MENDEL’S EXPERIMENTS
P1 generation
____
(_________)
parental
F1 generation
____
filial
(______=
offspring)
F2 generation
___
Principles of Dominance
Section 11-1
P Generation
Tall
Go to
Section:
Short
F1 Generation
Tall
Tall
F2 Generation
Tall
Tall
Tall
Short
Principles of Dominance
Section 11-1
P Generation
Tall
Go to
Section:
Short
F1 Generation
Tall
Tall
F2 Generation
Tall
Tall
Tall
Short
Principles of Dominance
Section 11-1
P Generation
Tall
Go to
Section:
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:
1. ONLY ______
ONE trait ____________
showed
F1
in the ____
generation BUT . . .
Missing trait ____________
returned in
2. ___________
F2 generation
the ____
in a _________
3:1 ratio
PATTERNS ARE THE KEY
Who is the “father” of genetics?
A. Robert Hooke
B. Charles Darwin
C. Gregor Mendel
D. Anton Van Leeuwenhoek
What is it called when
the pollen of a plant
fertilizes an egg of
the same plant?
Mendel decided that there must
be a __________________
that
pair of FACTORS
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
CHOICES for a
_______
trait are called
___________.
ALLELES
What are the “factors” that
Mendel thought were
responsible for controlling
traits?
A. Homologous chromosomes
B. Meiosis
C. Mitosis
D. Genes
Different gene choices for a
trait are called ____________.
_______________
DOMINANT = An allele that
________
HIDES the presence of another
allele. Dominant alleles represented
with CAPITAL letters.
RECESSIVE = An allele
_________________
that __________________
is hidden by the
presence of another allele. Recessive
alleles represented with lowercase
letters.
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
PROBABILITY &
PUNNETT SQUARES
11-2
O T T F F S S E __
What comes next?
It’s EASY if you know the PATTERN!
(Just like Punnett Squares)
1
O
N
E
2
T
W
O
3
T
H
R
E
E
4
F
O
U
R
5
F
I
V
E
6
S
I
X
7 8
S E
E I
V G
E H
N T
9
__
N
I
N
E
PROBABILITY
____________________
is the __________
likelihood that a
particular _________________
event will occur
It can be written as a:
1/4
Fraction ____
25%
Percent ____
1:3
Ratio ____
COIN FLIP
There are 2 possible
outcomes:
HEADS
TAILS
The chance the coin will land on either one is:
1/2
____
50%
____
1:1
____
Alleles segregate randomly just like a coin
flip. . . So can use probability to predict
outcomes of genetic crosses.
PROBABILITIES
_____ outcomes ______
PAST
DON’Taffect _________ones
FUTURE
If last coin flip was heads… there is still a 50/50
chance the next flip will be heads too.
_____________works
______
Probability
predicting
best in ___________
a ________
number of events.
large
The more flips. . . The closer results will be to
the expected 50:50 average.
DOMINANT/RECESSIVE
Dominant allele is represented by a
_____________
____________
capital letter.
(usually the first letter of the trait)
Recessive allele is represented by the SAME
____________
lower-case
_________________
letter.
T
EX: Tall = ______
NOT S for short
t
Short =______
HOMOZYGOUS
HETEROZYGOUS
When both alleles in the pair are
the _______,
SAME the organism is
_______________
HOMOZYGOUS or __________
PURE
TT
tt
EX: ____
or ___
When both alleles in the pair are
_____________,
DIFFERENT the organism is
HETEROZYGOUS or _____________
HYBRID
_________________
Ex: ____
Tt
Using the alphabet letter
D
text a homozygous
genotype.
Using the alphabet letter
G
text a heterozygous
genotype.
PHENOTYPE/GENOTYPE
genetic makeup
The ________________
of an organism
is itsGENOTYPE
_____________
appearance
The ____________of
an organism is
PHENOTYPE
its _____________
MAKING A CROSS for
only a ONE
__________
GENE trait =
MONOHYBRID
CROSS
____________________
A Punnett square for
a MONOHYBRID
CROSS looks like
this:
PUNNETT SQUARES
are used to show possible offspring
from a cross between 2 parents
Parent alleles go at
_______________
top and on left side
Boxes show
T
possible
____________
offspring combinations t
___________________
T
T
STEPS FOR MAKING CROSSES
Figure out what _________________
parent alleles
1. ___________
are
Choose
Punnett square __________
size
2. ________correct__________
Put in possible_______________________
parent gametes
3. ______
Fill in boxes with _____________________
offspring combinations
4. ______
probabilities phenotypes
5. Determine ____________of_____________&
genotypes
____________
IN PEA PLANTS
Tall is dominant over short
TALL = ____
T
SHORT = ____
t
LET’S MAKE A CROSS!
PURE TALL
X PURE SHORT
PURE TALL parent
What are the parent alleles?
TT

T
HOMOZYGOUS
_________

T
What gametes
can it make?
PURE SHORT parent
What are the parent alleles?
tt

t
HOMOZYGOUS
_________

t
What gametes
can it make?
T
T
t
Tt
Tt
t
Tt
Tt
ALL
_____
of the
offspring
100
____ %
___/4
4
will be
Tt PHENOTYPE _______
TALL
GENOTYPE _____
HYBRID TALL parent
What are the parent alleles?
Tt

T
_________
HETEROZYGOUS

t
What gametes
can it make?
T
t
T
TT
Tt
t
Tt
tt
GENOTYPES
TT
¼ = _____
Tt
½ = _____
tt
¼ = _____
TALL
3/4 or ____%
75
PHENOTYPES ____
_________
____
_________
1/4or ____%
SHORT
25
PRACTICE MAKING GAMETES
for a MONOHYBRID CROSS
Tall = ____
T
t
Short = ____
R
Round seeds = ___
r
Wrinkled seeds = ___
What are the possible gametes?
Homozygous Tall parent =

What gametes can it produce?
T

TT
T
What are the possible gametes?
PURE wrinkled parent =

What gametes can it produce?
r

rr
r
What are the possible gametes?
Heterozygous Round parent =

What gametes can it produce?
R

Rr
r
What are the possible gametes?
Hybrid Tall parent =

What gametes can it produce?
T

Tt
t