Genetics
Homozygous or
Heterozygous?
III. Gentics Terms
A. A _____________ is a long molecule of DNA.
B. Two connected copies of a chromosome are ______________.
C. A ___________ is a part of the DNA that has instructions for a
specific trait, like eye color or hair color.
D. An _____________is one form of a gene that has instructions
for a particular characteristic like blue eyes or brown eyes.
E. Some traits are _______________. They can hide other traits.
1. We use capital letters to represent _____________
alleles.
TT
Tt
tt
IV. Predicting Genetic Outcomes
A. Punnet squares are a tool to help us determine what
genotypes the offspring of certain parents might have.
B. Sample Cross:
Key: T = Tall pea plants, t = Short pea plants
2. Brown hair and brown eyes are _____________ traits.
F. Some traits can be hidden by dominant traits. These traits are
________________.
1. We use lower case letters to represent _____________
alleles.
2. Blue eyes and blonde hair are ______________ traits.
G. If an organism has two alleles that are the same, we call that
organism ___________________. (Ex: TT, tt)
H. If an organism has two different alleles of the same gene, we
call that organism ________________. (Ex: Tt) ***A
heterozygous organism shows the dominant trait.***
Phenotype?
% Dominant Phenotype (Tall): ________
% Recessive Phenotype (Short): ________
Ratio of Dominant to Recessive: ________
Key:
P = purple flowers
p = white flowers
Key:
R = round seeds
r = wrinkled seeds
P = purple flowers
p = white flowers
R = round seeds
r = wrinkled seeds
Parent 1: ____________________ Parent 2:____________________
Parent 1: ____________________ Parent 2:____________________
% Dominant Phenotype: ________
% Dominant Phenotype: ________
% Recessive Phenotype: ________
% Recessive Phenotype: ________
Ratio of Dominant to Recessive: ________
Ratio of Dominant to Recessive: ________
Parent 1: ____________________ Parent 2:____________________
Parent 1: ____________________ Parent 2:____________________
% Dominant Phenotype: ________
% Dominant Phenotype: ________
% Recessive Phenotype: ________
% Recessive Phenotype: ________
Ratio of Dominant to Recessive: ________
Ratio of Dominant to Recessive: ________