Heredity and Genetics
1. Heredity is the passing of characteristics from ______________ to _______________.
2. Genetics is the branch of biology that…
3. ___________________ ___________________ is the father of genetics.
4. Why were garden peas good subjects for the study of genetics?
- have traits that are inherited by _________________________________
- have male and female __________________________ parts enclosed in the same structure
Mating could be done with the bristles of a brush!
- are _______________, grow easily, mature quickly, and produce ____________________
5. For each inherited characteristic, an individual has ________ copies. (One copy is inherited
from _____________________ and one copy is inherited from ______________________.)
6. Alleles are the ____________________ ____________________ of a gene. (For example,
the two versions of the gene for pea seed color are _____________________ and
____________________.)
7. The expressed form of a trait is called __________________________. Ex: __________
8. The trait that is not expressed if the dominant allele is present is called ________________.
Ex: _______
9. What process is used to make gametes? ________________________
During fertilization each gamete ____________, each gamete contributes one
_______________ to the offspring.
So you get ½ of your genes from your mom and ½ of your genes from your dad!!
10. Genotype is the…
Example:
11. Phenotype is the …
Example:
12. Homozygous- the two alleles present for a character are _______________. Ex: _______
13. Heterozygous- the two alleles present for a character are ________________. Ex: ____
14. Labeling the Generations:
____ generation – _______________ generation
______ Generation – first filial, offspring of the ______ generation
______ generation – second filial, offspring of the _____ generation
Probability
15. ________________________ is the likelihood that a specific event will occur.
3 Laws of Probability
First Law: Each trial of a chance event is __________________ of all other trials of the same
change event.
Application: What is the chance that you will roll a 1 the first time you roll a dice? ______
Problem: What is the chance that you will roll a 1 the second time you roll a dice? ______
Second Law (also called Law of Muliplication): The chance of independent events occurring
together is the product of the chances for each independent event occurring separately.
Application: Two people have a coin. They are tossing the coins at the same time. What is
the chance that both will come up heads?
Problem: What is the chance that both will come up tails? _______________
Problem: What is the probability that a couple will have four boys in a row? ____________
Problem: If one out of two students is female and one out of eight students is left handed
and one out of 12 is red haired, what is the probability that the next person you will see will
be left-handed, red-haired girl?
__________________________
Third Law (also called Law of Addition): The probability of an event that can occur in two
or more different ways is the sum of the separate possibilities of those ways.
Application: Two people have a coin. They are tossing the coins at the same time.
Problem: What is chance that one will come up heads and the other come up tails? _______
Now, let’s see if this works in the real world…
Each student will flip a penny 10 times and record the results. Based on probability, how many
heads should there be? Tails?
Your results: Heads______ Tails ______
Class results: Heads _______ Tails ________
Which results are closest to your prediction based on probability? ___________
Each student needs a penny and a partner!
Each student with their partner each flip their penny. Record the results whether it be 2 heads, 2
tails or 1 heads and 1 tails. Do this 20 times.
What is the predicted result based on probability? ___________
Your results: HH_____ HT _____ TT_____
Class results: HH _____ HT _____ TT______
Which are closer to the predicted results?
Application Questions (Show your work)
a.
Miguel has just received an IPOD as a gift. He has downloaded 3 country music songs,
1 rhythm and blues song, 5 rap songs, and 1 song that is the theme song to his favorite
movie. If the IPOD is set on playing these songs at random, what is the probability that
he will hear a country music song?
b.
Sherri has a pocket full of colored candy jelly beans. She has 6 pink jelly beans, 3 yellow
jelly beans, 10 green jelly beans, and 1 orange jelly bean. What is the probability that
Sherri will select a green jelly bean and then, without replacing it, randomly select an
orange jelly bean from her pocket?
16. What is a monohybrid cross?
17. Monohybrid cross practice using Punnett Squares:
a. Cross two heterozygous individuals. ________ x _________
Gametes: ________ _________
Genotypic ratio: __________
Phenotypic ratio: __________
b. Cross a homozygous dominant with a homozygous recessive using the same trait.
___________ x ____________
Gametes: _______
________
Genotypic ratio: ____________
Phenotypic ratio: ____________
c. Cross a homozygous dominant with a heterozygous using the same trait.
__________ x ____________
Gametes: ________
________
Genotypic ratio: _____________
Phenotypic ratio: _____________
18. What is a test cross?
What is a test cross used to determine?
Problem: Consider that tallness in pea plants is dominant to dwarfism. A horticulturalist has a
tall plant, however is unaware of its genotype. She has a contract to produce all tall plants.
Show the test cross she will have to make in order to be sure that the tall plant she uses to make
offspring is a purebreeding tall plant. What are the possibilities with a tall plant?
Possible genotypes of her plant?
_______ or _________
Genotypes of the plant she will
cross with her plant? ________