Download File - Ms. Park`s Ogden Science Website

1/14/13 Bell Ringer
Create a punnett square for this situation:
In guinea pigs, the allele for black fur (B) is
dominant over the allele for white fur (b). In a cross
between a heterozygous black guinea pig (Bb) and a
homozygous white guinea pig (bb), what is the
probability that an offspring will have white fur?
Objective:
To review heredity and probability
B
b
b
Bb
bb
b
Bb
bb
Agenda
 Go over homework
 Pg. 123 #1-3
 Finals study guide
 Review of Punnett Squares
 Get started on homework
Homework pg. 123 #1-3

What is probability?

A number that describes how likely it is that an event will
occur.
 If you know the parents’ alleles for a trait, how can you use
a Punnett square to predict the probable genotypes of the
offspring?

A punnett square shows all the possible combinations of
alleles that can result from a genetic cross.
 A pea plant with round seeds has the genotype Rr. You
cross this plant with a wrinkled-seed plant, genotype rr.
What is the probability that the offspring will have wrinkled
seeds? (Use a Punnett square to help with the prediction.)
R
r

50%
r
Rr
rr
r
Rr
rr


Define genotype and phenotype

Genotype – an organism’s genetic makeup

Phenotype – an organism’s physical appearance
Explain how two organisms can have the same phenotype but
different genotypes. Give an example.


A pea plant has a tall stem. What are its possible genotypes?


TT or Tt
What is codominance? Give an example of codominant alleles and
explain why they are codominant.


A heterozygous organism will have the same phenotype as an organism
that is homozygous for a dominant allele. An example would be a tall
pea plant can be either heterozygous or homozygous.
An inheritance pattern in which alleles for a trait are neither dominant
nor recessive. For example, the alleles for black and white chicken
feathers are codominant because both colors show.
What is the phenotype of a chicken with the genotype FBFW?

Black and white feathers
Semester 1 Final
 Schedule
 This week:
 Monday – Finals overview
 Tuesday – Pass out study guide
 Wednesday – Go over study guide
 Thursday – Review Game/ Computer Lab
 Friday – Review Game /Computer Lab
 Study Tips
 Things to use:
 Book
 Composition Notebook
 Any handouts, diagrams, foldables
 Ms. Park’s science website
 Videos online
 You must study!
 Building good study habits
 Don’t calculate grade, just do your best!
 Review each day
 Test yourself
Study Guide


Scientific process
Living things


What is life

Characteristics of living things

Needs of living things
Classification



Domain, kingdom, phyla, class,
order, family, genus
Cell processes

Cell parts (identify and function)

Chemical compounds in cells

Photosynthesis

Cellular respiration

Cell cycle

Interphase

Mitosis

Cytokinesis
Genetics

Mendel’s work

Probability

Punnett square

Finding percentage

Vocabulary words
Punnett Square Practice
W = long whiskers
 Homozygous = WW
w = short whiskers
 Heterozygous = Ww
What percentage of offspring
would be expected to have
short whiskers from the cross
of two long-whiskered seals,
one that is homozygous
dominant and one that is
heterozygous?
W
W
W
WW W
W
w
Ww
Ww
Punnett Square Practice
R = Red flower
R
r
R
RR
Rr
r
Rr
rr
r = white flower
If two heterozygous red flowers are
mixed, what are the possible
phenotypes and genotypes that can
occur?
Heterozygous = Rr
 Genotypes

RR, Rr, rr
 Phenotypes

RR = Red

Rr = Red

rr = white
Punnett Square Practice
In humans, wavy hair (HcHs) results
by the co-dominant situation of curly
hair (Hc) and straight hair (Hs).
What are the possible results if a
curly-haired man and wavy-haired
woman have children.
Hc
Hc
Hs
HcHs
HcHs
Hc
HcHc
HcHc
 Genotypes
 Hc Hs
 Hc Hc
 Phenotypes

HcHs = Wavy hair

HcHc = Curly hair