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Cells and Heredity Chapter 3 Genetics: The Science of Heredity
Section 1 Mendel’s Work
Key Terms:
heredity trait
recessive allele
genetics
hybrid
fertilization
purebred
gene
alleles
dominant allele
1. ____________________ an organism that has two different alleles for a trait; an organism
that is heterozygous for a particular trait
2. ____________________ the scientific study of heredity
3. ____________________ the set of information that controls a trait; a segment of DNA on a
chromosome that codes for a specific trait
4. ____________________ the process in which an egg cell and a sperm cell join to form a new
organism
5. ____________________ the different forms of a gene
6. ____________________ an allele whose trait always shows up in the organism when the
allele is present
7. ____________________ a characteristic that an organism can pass on to its offspring through
its genes
8. ____________________ an allele that is masked/hidden when a dominant allele is present
9. ____________________ the offspring of many generations that have the same traits
10. ___________________ the passing of traits from parents to offspring
Key Concepts:
What were the results of Mendel’s experiments, or crosses?
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What controls the inheritance of traits in an organism?
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Cells and Heredity Chapter 3 Genetics: The Science of Heredity
Section 2 Probability and Heredity
Key Terms:
probability Punnett square
codominance
phenotype
genotype
homozygous
heterozygous
1. ____________________ having two different alleles for a trait
2. ____________________ an organism’s genetic makeup, or allele combinations
3. ____________________ a chart that shows all the possible combinations of alleles that can
result from a genetic cross
4. ____________________ a number that describes how likely it is that an event will occur
5. ____________________ an organism’s physical appearance, or visible traits
6. ____________________ a condition in which neither of two alleles of a gene is dominant or
Recessive
7. ____________________ having two identical alleles for a trait
Key Concepts:
What is probability and how does it help explain the results of genetic crosses?
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What is meant by genotype and phenotype?
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What is codominance?
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Cells and Heredity Chapter 3 Genetics: The Science of Heredity
Section 3 The Cell and Inheritance
Key Terms:
meiosis
1. ____________________ the process that occurs in the formation of sex cells (sperm and egg)
by which the number of chromosomes is reduced by half
Key Concepts:
What role do chromosomes play in inheritance?
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What events occur during meiosis?
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What is the relationship between chromosomes and genes?
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Cells and Heredity Chapter 3 Genetics: The Science of Heredity
Section 4 The DNA Connection
Key Terms:
messenger RNA
transfer RNA
1. ____________________ RNA that copies the coded message from DNA in the nucleus and
carries the message into the cytoplasm
2. ____________________ RNA in the cytoplasm that carries an amino acid to the ribosome
and adds it to the growing protein chain
Key Concepts:
What forms the genetic code?
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How does a cell produce proteins?
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How can mutations affect an organism?
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Test Preparation:
Chapter 3 Study Guide p. 104-105
Go online for Self-Assessment: PHSchool.com (Web Code: cea-3030)
Study this study guide 
Extra Credit Opportunities *Remember to print and turn in your answers to
receive credit.
Links on probability and genetics (Web Code: scn-0332)- Choose one of the links
and read the article. Print the article and write a 5 sentence summary of what you
learned. (worth 10 points)
Protein Synthesis Activity (Web Code: cep-3034)