Transcript Mendel Discovers “Genes” 9-1

BellChallenge
1. In the Punnett square shown, the genotypes of the
offspring are ____________________.
2. In the Punnett square shown, the phenotype of the
offspring are ____________________.
3. How many recessive alleles for a trait must an
organism inherit in order to show that trait?
T = Tall
t = Short
Agenda
• Review Sec. 11-1 & 11-2
• Due Friday: 11-1 & 11-2 Vocabulary Review 10
different words (term, your definition, picture)
IAN 54
• Homework: bring a coin for tomorrow’s lab &
complete Punnett Square Practice #1 IAN 55
• Wed- Traits lab (coins needed)
• Final exams are next week (review weak concepts)
Sec. 11-1
Transmission of characteristics from
_______________________is
called
parents
to offspring
___________________.
heredity
The SCIENCE
_________ that studies _____
how those
characteristics are _________
from one
passed on
generation to the next is called
___________________
Genetics
http://hus.yksd.com/distanceedcourses/YKSDbiology/lessons/FourthQuarter/Chapter11/11-1/images/MendelExperiment.gif
Mendel designed
____________ using
experiments
__________
Pea
plants in the
monastery garden
_______
MALE part of flower makes
Pollen (sperm)
___________
__________
FEMALE part of flower makes
_______
egg cells
http://www.cedarville.edu/academics/education/resource/schools/chca/2scideb/debwebpv.htm
In pea plants, the pollen normally joins
with an egg from the _______
same plant
(=_______________
) so seeds have
Self pollinating
“_________________”
ONE parent
http://hus.yksd.com/distanceedcourses/YKSDbiology/lessons/FourthQuarter/Chapter11/11-1/images/MendelExperiment.gif
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.
http://hus.yksd.com/distanceedcourses/YKSDbiology/lessons/FourthQuarter/Chapter11/11-1/images/MendelExperiment.gif
MENDEL’S PEA EXPERIMENTS
Mendel ____________________
removed pollen
making parts and ____________
added pollen
from _______
anotherplant.
This allowed him to
_____________ plants
cross-breed
with ______________
different
characteristics and
________
study the results
http://hus.yksd.com/distanceedcourses/YKSDbiology/lessons/FourthQuarter/Chapter11/11-1/images/MendelExperiment.gif
specific characteristic is called a
A _____________________
____________
trait
studied 7 traits in peas (ex. Seed
Mendel ______________
shape).
Different gene choices for a trait are called
alleles (ex. round or wrinkled).
Pearson Education Inc,; Publishing as Pearson Prentice Hall
MENDEL’S EXPERIMENTS
P1 generation
____
(_________)
parental
F1 generation
____
filial offspring)
(______=
F2 generation
___
We now know that Mendel’s
factors are genes carried
________________
on the pair of
Homologous
chromosomes
__________
HOMOLOGOUS
_____________ chromosomes
SEPARATE during
________________
ANAPHASE I (meiosis)
SEGREGATION
= _________________
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Crossover.gif
Image modified from:
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Crossover.gif
Meiosis Review
•Meiosis- (initial step of sexual reproduction that produces
gametes)
•Two divisions- meiosis I & meiosis II
•Trigger words- homologous chromosomes, synapsis, crossing
over, segregation
•Diploid (46) → 4 haploids (23)
•Spermatogenesis- produces 4 sperm
•Oogenesis- produces 1 viable egg & 3 polar bodies
EXPLAINING the F1 CROSS
SEGREGATION
LAW OF ___________________
alleles are separated
when the F1 plants
______________
make gametes
When these gametes recombined to
make the F2 generation, the
recessive
_____________
trait
reappears
_______________
in ¼ of the
offspring
Image from: BIOLOGY by Miller & Levine; Prentice Hall Publishing ©2006
What are the possible gametes?
Homozygous Tall parent =
(homozygous dominant)

What gametes can it produce?
Tall = T
Short = t
T

TT
T
Round seeds = R
Wrinkled seeds = r
Phenotype= appearance
Genotype= genetic make-up (letters)
What are the possible gametes?
PURE wrinkled parent =
(homozygous recessive)

What gametes can it produce?
Tall = T
Short = t
r

rr
r
Round seeds = R
Wrinkled seeds = r
Phenotype= appearance
Genotype= genetic make-up (letters)
What are the possible gametes?
Heterozygous Round parent =
(heterozygous dominant)

What gametes can it produce?
Tall = T
Short = t
R

Rr
r
Round seeds = R
Wrinkled seeds = r
Phenotype= appearance
Genotype= genetic make-up (letters)
What are the possible gametes?
Hybrid Tall parent =
(heterozygous dominant)

What gametes can it produce?
Tall = T
Short = t
T

Tt
t
Round seeds = R
Wrinkled seeds = r
Phenotype= appearance
Genotype= genetic make-up (letters)
PROBABILITY &
PUNNETT SQUARES
11-2
PROBABILITY
____________________
is the __________
likelihood that a
particular _________________
event will occur
It can be written as a:
1/4
Fraction ____
25%
Percent ____
1:3
Ratio ____
http://www.arborsci.com/CoolStuff/CoinFlip.jpg
COIN FLIP
There are 2 possible
capital
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. (The more trials in an
experiment, the more precise your data will be)
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
Yellow is dominant over green
Yellow = Y
green = y
LET’S MAKE A CROSS!
PURE Yellow X PURE Green
Homozygous yellow= YY
Homozygous green= yy
PURE Yellow parent
What are the parent alleles?
YY

Y
_________
HOMOZYGOUS

Y
What gametes
can it make?
PURE Green parent
What are the parent alleles?
yy

y
HOMOZYGOUS
_________

y
What gametes
can it make?
Y
Y
y Yy
Yy
Yy
Yy
y
Test cross= mating
homozygous dominant
with homozygous
recessive
_____
ALL
of the
offspring
100
____ %
___/4
4
will be
Yy PHENOTYPE _______
Yellow
GENOTYPE _____
HYBRID Yellow parent
What are the parent alleles?
Yy

Y
_________
HETEROZYGOUS

y
What gametes
can it make?
Y
y
Y YY
Yy
y Yy
yy
GENOTYPES
YY
¼ = _____
Yy
½ = _____
yy
¼ = _____
yellow
3/4 or ____%
75
PHENOTYPES ____
_________
____
_________
1/4or ____%
green
25
Interest Grabber
Section 11-2
Tossing Coins
If you toss a coin, what is the probability of getting
heads? Tails? If you toss a coin 10 times, how many
heads and how many tails would you expect to get?
Working with a partner, have one person toss a coin
ten times while the other person tallies the results on a
sheet of paper. Then, switch tasks to produce a
separate tally of the second set of 10 tosses.
Go to
Section:
Interest Grabber Answers
1.
Assuming that you expect 5 heads and 5 tails in 10 tosses, how do the
results of your tosses compare? How about the results of your partner’s
tosses? How close was each set of results to what was expected?
Results will vary, but should be close to 5 heads and 5 tails.
2.
Add your results to those of your partner to produce a total of 20 tosses.
Assuming that you expect 10 heads and 10 tails in 20 tosses, how close
are these results to what was expected?
The results for 20 tosses may be closer to the predicted 10 heads and 10 tails.
3.
If you compiled the results for the whole class, what results would you
expect?
The results for the entire class should be even closer to the number predicted by
the rules of probability.
4.
How do the expected results differ from the observed results?
The observed results are usually slightly different from the
expected results.
SOUTH DAKOTA
CORE SCIENCE STANDARDS
LIFE SCIENCE:
Indicator 1: Understand the fundamental structures,
functions, classifications, and mechanisms found
in living things
9-12.L.1.1. Students are able to relate cellular
functions and processes to specialized
structures within cells.
Storage and transfer of genetic information
SOUTH DAKOTA
CORE SCIENCE STANDARDS
LIFE SCIENCE:
Indicator 2: Analyze various patterns and products
of natural and induced biological change.
9-12.L.2.1. Students are able to predict inheritance
patterns using a single allele. (APPLICATION)
Core High School Life Science
Performance Descriptors
High school students
performing at the
ADVANCED level:
predict how traits are transmitted from parents to offspring
High school students
performing at the
PROFICIENT level:
explain how traits are transmitted from parents to offspring;
High school students
performing at the
BASIC level
identify that genetic traits can be transmitted from parents to
offspring;