Name _____________________________________________
Chapter 3 Study Guide – Mendel, Heredity, and Genetics
1. What does a punnett square show?
a. All the possible outcomes of a genetic cross
b. Only the dominant alleles in a genetic cross
c. Only the recessive alleles in a genetic cross
d. All of Mendel’s discoveries about genetic crosses
2. What is the chromosome theory of inheritance?
a. Chromosomes are carried from parents to offspring on hybrids.
b. Genes are carried from parents to offspring on chromosomes.
c. Hybrid pairs of chromosomes combine to form offspring.
d. Codominant genes combine to form new hybrids.
3. Which of the following terms describes a pattern of inheritance in which one allele is
only partially dominant?
a. Codominance
b. Polygenic inheritance
c. Multiple alleles
d. Incomplete dominance
4. What is the definition for meiosis? Meiosis is the process by which the number of
chromosomes is reduced by half as sex cells form.
Use the following information to fill in the blanks for numbers 5-9.
HH
Hh
hh
Has horns
Does not have horns
5. ____HH___ is an example of a homozygous dominant individual
6. ____Hh_____ is an example of a heterozygous individual
7. ____hh____ is an example of a homozygous recessive individual
8. _HH, Hh, or hh_____ is an example of a genotype
9. ____Has horns or does not have horns___ is an example of a phenotype
10. Having horns is dominant over not having horns. What is the genotype AND phenotype
for a recessive individual. Genotype = hh
Phenotype = does not have horns
ESSAYS:
11. In pea plants, green pod color is dominant over yellow pod color. Use a punnett square
to help you EXPLAIN why a plant with yellow pods can never be a hybrid.
G
G
GG
g
Gg
To have a yellow pod as offspring, the only allele combination is
gg, which is homozygous recessive, not a hybrid. A hybrid allele
would still show green pods as a phenotype.
g
Gg
gg
12. Mendel crossed a purebred tall and purebred short pea plant. Set up and interpret a punnett
square to explain the results.
T
t
t
Tt
Tt
T
Tt
All offspring from this cross will be tall pea plants as they each
have one dominant allele.
Tt
13. Using the punnett square below, give the percentage of white and percentage of purple
flowered offspring.
White flowers = 75%
Purple flowers = 25%
Vocab word
Definition
Example
Purebred/
Homozygous
An offspring of crosses that has the same
form of traits
HH or hh
Hybrid/
Heterozygous
Having 2 different alleles for a particular
gene
Hh
Genotype
An organism’s genetic makeup, or allele
combinations
BB, Bb, or bb
Phenotype
Codominance
An organism’s physical appearance, or
visible traits.
A situation in which both alleles for a gene
are expressed equally.
Has freckles,
Brown hair, blue
eyes, etc.
White cow &
brown cow produce
a white and brown
cow.
Yellow is dominant
over blue.
Dominant
(allele)
Probability
Allele
Recessive
(allele)
An allele whose traits always shows up in
the organism when the allele is present
A number that describes how likely it is
that an event will occur.
Offspring will be
yellow is alleles are
YY or Yy.
There is a 50%
chance the offspring
will have freckles.
Different forms of a gene
GG, Gg, or gg
An allele that is hidden whenever the
dominant allele is present.
bb
TEST DATE: Thursday, 12/10
Study Resources for your test:
1. Vocabulary
a. Filled in vocab on schoolwires
2. Class Notes for each section
a. Mendel
b. Punnett Squares
c. Patterns of Inheritance
d. Meiosis
3. PowerPoints from class
a. On all sections listed above
4. Study Guide
a. Answers will be put on schoolwires on Tuesday
5. Jeopardy!!
a. PowerPoint on schoolwires page
b. Use this to quiz yourself
6. Textbook
a. Chapter 3
b. You can also try the chapter review in your textbook for extra practice (Pg 99101). Answers on my schoolwires page.
If you have questions, please ask Mrs. McFarland! Or you can e-mail me:
jmcfarland@ojrsd.com
HAPPY STUDYING!!