AP Biology Notes
Tuesday 3/17/2015
Goals for the day
1. Be able to define and use basic genetics
vocabulary
2. Be able to set up and complete a genetic
problem to predict the outcome of offspring
Question of the Day 3/17
Where do we get our “genetics” from?
Double Helix Discussion
• Last thoughts/questions??
• Turn in Discussion Day 3
• Hand in Character map & book on Friday
5. "We are like dwarfs sitting on the shoulders of giants. We
see more, and things that are more distant, than they did, not
because our sight is superior or because we are taller than
they, but because they raise us up, and by their great stature
add to ours.“
A. Discuss how you think this statement relates to the
discovery of the structure of DNA.
B. Discuss how this is relevant for all scientific
discovery/understanding, and research in other
fields in our modern world.
Keys to Success in Genetics Unit
1.
2.
3.
4.
ASK QUESTIONS
Take Notes
Go through problems
Make sure YOU understand how to work
each type of problem & understand the
“whys” of what we are doing
5. Stay on Task
6. ASK QUESTIONS
Genetics
Genetics – the study of how
organisms inherit different features
from their parents
• Parents send information about TRAITS
(characteristics ) to their offspring.
We refer to this information as a gene, which is
a segment of DNA that codes for a specific trait.
• GENES are found on chromosomes and are
made up of DNA.
Each individual has two copies of a gene, one
from each Parent. (One copy from _____ & One
from _______)
•An ALLELE is a – form of a trait
The two copies you have of your genes may or
may not have the same Information (or alleles).
Example: Both of your parents gave you an
ALLELE for the trait of “tongue rolling”
Example: Both of your parents gave you an
ALLELE for the trait of “tongue rolling”
Your Mom may have given you an allele that to
be able to roll your tongue & Your Dad might
have given you an allele to not be able to roll
your tongue.
So can you roll your tongue??
A DOMINANT trait – the Powerful trait (the
stronger trait) always represented with a Capital
letter
Example:
A RECESSIVE trait – the weaker trait, can be
hidden by a dominant allele, always represented
with a lowercase letter
Example:
The ability to roll your tongue is a DOMINANT
trait, and is therefore represented with capital “T”
Note: the choice of letter usually comes from the
name of the DOMINANT trait.
Not being able to roll you tongue is a recessive
trait, and is therefore represented with a
lowercase “t”
•So if tongue rolling is dominant and a person
has one dominant & one recessive allele can
they roll their tongue???
• If the ALLELES you got from each parent are
the same alleles the individual is said to be
Homozygous for the trait.
– Ex:
• Homologous chromosomes are chromosomes
with the ______ information, size, & shape.
Homo means the _________.
• If an individual has different alleles the
individual is said to be Heterozygous for the
trait.
• Ex. _______
• Hetero means the opposite of homo, it means
DIFFERENT
Homozygous or Heterozygous?
AA
Aa
bb
Tt
pp
Qq
PHENOTYPE its ______________ appearance.
What an organism _________ like. I remember
“PH” Phenotype/Physical
Examples of Phenotypes:
Height
Or anything else you can SEE!
GENOTYPE – the types of ALLELES that an
organism has for a particular trait (i.e. tongue
rolling)
Examples of Genotypes:
,
,
(The
combination of the two alleles you have for a
trait is your genotype)
GENOTYPE – the types of ALLELES that an
organism has for a particular trait (i.e. tongue
rolling)
Homozygous or Heterozygous refer to an
organism’s ____________________
(Phenotype or Genotype)
If having Acne is dominant to not having Acne
write the phenotypes:
Make yourself a Key each time!!
AA_____________
Aa_____________
aa______________
If having Big eyes is dominant to having
small eyes write the possible GENOTYPES:
Make yourself a Key each time!!
Big Eyes _____________
small eyes_____________
We defined the word “Hybrid” for our purposes it
means two different parents or traits. If you have a
ring that is a gold hybrid, it is made of some different
things besides gold. What word that we discussed
today would be a synonym (mean the same thing) as
the word “Hybrid”?
•Hybrid = ____________
If “Pure” means being the same throughout, as in pure
gold has only gold. What word we discussed today
would be a synonym (mean the same thing) as the
word “Purebred”?
Purebred = ________________________
Parents & Offspring
• P1 = Par
Keys to Success in Genetics Unit
1.
2.
3.
4.
ASK QUESTIONS
Take Notes
Go through problems
Make sure YOU understand how to work
each type of problem & understand the
“whys” of what we are doing
5. Stay on Task
6. ASK QUESTIONS
New Tools
Punnett Square – diagram used to predict the
outcome of a genetic cross.
Created by Reginald Punnett (1875 –1967), a
British geneticist, in the early 1900s
New Tools
Punnett Square – diagram used to predict the
outcome of a genetic cross.
Legend
Parents
Cross it
Genotypic Phenotypic
Ratio
Ratio
Tongue Roller Problem #1
Tongue Rolling is dominant to not being
able to roll your tongue (non-roller). Cross a
Heterozygous tongue roller with someone
who cannot roll their tongue.
Tongue Roller Problem #1
to not being able to
roll your tongue (non-roller). Cross a
with someone who
.
Legend Parents
Cross it
Genotypic Phenotypic
Ratio
Ratio
Tongue Roller Problem #1
to not being able to
roll your tongue (non-roller).
Legend – pick letters to represent each trait and
define the phenotype they code for.
Legend Parents
Cross it
Genotypic Phenotypic
Ratio
Ratio
Tongue Rolling is Dominant to non-roller
Cross a
who
with someone
.
Parents – Use the word problem to determine the
genotype of each parent.
Legend
T = Roller
t=
Non-roller
Parents
Cross it
Genotypic Phenotypic
Ratio
Ratio
Using the Punnett Square
Cross it – 1. Break up the alleles from each
parent simulating meiosis, where different
chromosomes are separated into different
gametes(sex cells).
Legend Parents
T = Roller
Tt
t=
Non-roller
tt
Cross it
Genotypic Phenotypic
Ratio
Ratio
Using the Punnett Square
Cross it –
2. Determine the genotypes of the possible
zygotes made if each different kind of gamete
combined.
Legend Parents
T = Roller
Cross it
Tt
t=
Non-roller
T
t
tt
Genotypic Phenotypic
Ratio
Ratio
t
t
Tongue Rolling is Dominant to non-roller
Cross a Heterozygous tongue roller with someone who
cannot roll their tongue.
Genotypic Ratio – Write in the possible
genotypes, and then count the number of each that
are found within your Punnett square (Purple).
Legend Parents
T = Roller
Cross it
Tt
t=
Non-roller
tt
Genotypic Phenotypic
Ratio
Ratio
T
t
t
Tt tt
t
Tt tt
Tongue Rolling is Dominant to non-roller
Phenotypic Ratio – Write in the possible
phenotypes, and then count the number of each
that are found within your Punnett square
(Purple).
•You can also look at the genotype ratio and determine
which phenotype comes from each genotype.
Legend Parents Cross it
Genotypic Phenotypic
Ratio
Ratio
T = Roller
Tt
t=
Non-roller
tt
T
t
t
Tt tt
t
Tt tt
TT: Tt: tt
0:2:2
Tongue Rolling is Dominant to non-roller
Phenotypic Ratio – Write in the possible
phenotypes, and then count the number of each
that are found within your Punnett square
(Purple).
•You can also look at the genotype ratio and determine
which phenotype comes from each genotype.
Legend Parents Cross it
Genotypic Phenotypic
Ratio
Ratio
T = Roller
Tt
t=
Non-roller
tt
T
t
t
Tt tt
t
Tt tt
TT: Tt: tt Roller: 2
0:2:2
Non-roller:
2
Tongue Roller Problem #2
Tongue Rolling is dominant to not being able to
roll your tongue (non-roller). Cross a homozygous
dominant tongue roller with a Heterozygous
tongue roller.
Legend Parents
Cross it
Genotypic Phenotypic
Ratio
Ratio
Tongue Roller Problem #2
Tongue Rolling is dominant to not being able to
roll your tongue (non-roller).
Legend – pick letters to represent each trait and
define the phenotype they code for.
Legend Parents
Cross it
Genotypic Phenotypic
Ratio
Ratio
Tongue Roller Problem #2
Cross a homozygous dominant tongue roller with
a Heterozygous tongue roller.
Parents – Use the word problem to determine the
genotype of each parent.
Legend Parents
T = Roller
t=
Non-roller
Cross it
Genotypic Phenotypic
Ratio
Ratio
Tongue Roller Problem #2
Cross a homozygous dominant tongue roller with
a Heterozygous tongue roller.
Parents – Use the word problem to determine the
genotype of each parent.
Legend Parents
T = Roller
TT
t=
Non-roller
Tt
Cross it
Genotypic Phenotypic
Ratio
Ratio
Tongue Roller Problem #2
Cross it – 1. Break up the alleles
Legend Parents
T = Roller
TT
t=
Non-roller
Tt
Cross it
Genotypic Phenotypic
Ratio
Ratio
Tongue Roller Problem #2
Cross it – 2. Fill in the Square
Legend Parents
T = Roller
Cross it
TT
t=
Non-roller
T
T
Tt
Genotypic Phenotypic
Ratio
Ratio
t
T
Tongue Roller Problem #2
Cross a homozygous dominant tongue roller with
a Heterozygous tongue roller.
Cross it – Use the word problem to determine the
genotype of each parent.
Legend Parents
T = Roller
Cross it
TT
t=
Non-roller
Tt
Genotypic Phenotypic
Ratio
Ratio
T
T
T TT TT
t
Tt Tt
Tongue Rolling is Dominant to non-roller
Cross a homozygous dominant tongue roller with a
Heterozygous tongue roller.
Genotypic Ratio – Write in the possible genotypes, and
then count the number of each that are found within your
Punnett square (Purple).
Legend Parents Cross it
T = Roller
TT
t=
Non-roller
Tt
Genotypic
Ratio
T
T
T TT TT
t
Tt Tt
Phenotypic
Ratio
Possible Gametes
TT
Tt
tt
QUESTIONS???
1. Finish problems on back of notes
– check with Ms. Jacobs
2. Work on Genetics problem set 1