1. 7th Grade Cells and Heredity (Mod A) Unit 2 Lesson 4 - Heredity
– Heredity intro – includes some vegetative reproduction, mitosis & meiosis, dominant & recessive, genetic engineering

2. Give Peas a Chance What is heredity?
Unit 2 Lesson 4 Heredity
Give Peas a Chance
What is heredity?
Traits, such as hair color, result from the information stored in genetic material.
Heredity is the passing of genetic material from parents to offspring.
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3. What did Gregor Mendel discover about heredity?
Unit 2 Lesson 4 Heredity
What did Gregor Mendel discover about heredity?
Gregor Mendel was an Austrian monk. In the 1800s, Mendel performed the first major experiments in heredity.
Mendel studied seven characteristics of _____ _________.
A characteristic is a feature that has different forms in a population.
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4. What did Gregor Mendel discover about heredity?
Unit 2 Lesson 4 Heredity
What did Gregor Mendel discover about heredity?
The seven different characteristics Mendel studied were ______ _______, flower and pod ________, seed _______, seed _______, _____ shape, pod color, and ______ ________.
Each characteristic had two different forms. These different forms are called _______.
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5. What did Gregor Mendel discover about heredity?
Unit 2 Lesson 4 Heredity
What did Gregor Mendel discover about heredity?
Mendel studied each characteristic separately, always starting with plants that were ______ _________.
True-breeding plants always produce offspring with the ______ trait if allowed to self-pollinate naturally.
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6. What did Gregor Mendel discover about heredity?
Unit 2 Lesson 4 Heredity
What did Gregor Mendel discover about heredity?
Mendel crossed plants that were true-breeding for producing yellow seed pods with plants that were true-breeding for green seed pods.
All of the plants from the first generation produced ______ seed pods.
Mendel called the green seed pod the dominant trait, and the yellow seed pod the recessive trait.
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7. What did Gregor Mendel discover about heredity?
Unit 2 Lesson 4 Heredity
What did Gregor Mendel discover about heredity?
Next, Mendel let the first generation plants ____ __________.
Out of the generation that resulted, called the _________ ________, about three-fourths had green seed pods and one-fourth had yellow pods.
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8. What did Gregor Mendel discover about heredity?
Unit 2 Lesson 4 Heredity
What did Gregor Mendel discover about heredity?
The _________ trait had seemed to disappear in the first generation, but it _________ in the second generation.
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9. What did Gregor Mendel discover about heredity?
Unit 2 Lesson 4 Heredity
What did Gregor Mendel discover about heredity?
Mendel hypothesized that each plant must have two heritable “factors” for each trait, one from each _________.
Some traits, such as yellow color, could only be observed if a plant had _____ of the same factors.
A plant with two different factors would show the __________ factor but be able to pass on _____ factors to its offspring.
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10. It’s in Your Genes! How are traits inherited?
Unit 2 Lesson 4 Heredity
It’s in Your Genes!
How are traits inherited?
Mendel’s ideas can be further explained by our modern understanding of _______.
What Mendel called “factors” are actually segments of DNA known as _____.
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11. How are traits inherited?
Unit 2 Lesson 4 Heredity
How are traits inherited?
Genes are segments of DNA. They give instructions for producing a certain characteristic.
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12. How are traits inherited?
Unit 2 Lesson 4 Heredity
How are traits inherited?
The offspring has ___ versions of the same gene for every characteristic—one from each parent.
Different versions of a gene are known as alleles.
Dominant alleles are shown with a ______ letter, and recessive alleles are shown with a lowercase version of the same letter.
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13. How are traits inherited?
Unit 2 Lesson 4 Heredity
How are traits inherited?
An organism with one _________ and one ___________ allele for a gene is heterozygous for that _______.
An organism with two of the same alleles for a gene is homozygous for that gene.
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14. How are traits inherited?
Unit 2 Lesson 4 Heredity
How are traits inherited?
The _____________ of alleles that you inherited from your _________ is your genotype.
Your observable traits make up your _________.
The phenotypes of some traits follow patterns similar to the ones Mendel discovered.
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15. How are traits inherited?
Unit 2 Lesson 4 Heredity
How are traits inherited?
The dominant allele contributes to the phenotype if _____ or ______copies are present in the genotype.
The recessive allele contributes to the phenotype only when _____ copies of it are present.
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16. How are traits inherited?
Unit 2 Lesson 4 Heredity
How are traits inherited?
If one chromosome in the pair contains a dominant allele and the other contains a recessive allele, the dominant allele determines the _____________.
This is called __________ dominance.
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17. How are traits inherited?
Unit 2 Lesson 4 Heredity
How are traits inherited?
Some characteristics are a result of several genes ________ _________.
Sometimes, ____ gene influences more than one trait.
For example, many genetic disorders, such as sickle cell anemia, are linked to a single gene but affect many _______.
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18. How are traits inherited?
Unit 2 Lesson 4 Heredity
How are traits inherited?
Sometimes, the ____________ can influence an organism’s phenotype.
Some traits are acquired only from one’s environment and are not inherited.
For example, your ability to _______ and ______is an acquired trait.
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19. Bending the Rules What are the exceptions to complete dominance?
Unit 2 Lesson 4 Heredity
Bending the Rules
What are the exceptions to complete dominance?
Some traits do not follow the pattern of _________ ___________.
For traits that show incomplete dominance and codominance, one trait is not completely dominant over another.
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20. What are the exceptions to complete dominance?
Unit 2 Lesson 4 Heredity
What are the exceptions to complete dominance?
In incomplete dominance, each allele in a heterozygous individual influences the phenotype.
The result of incomplete dominance is a phenotype that is a blend of the phenotypes of the parents.
An example of this in humans is hair. A person with one allele for straight hair and one allele for curly hair will have wavy hair.
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21. What are the exceptions to complete dominance?
Unit 2 Lesson 4 Heredity
What are the exceptions to complete dominance?
For a trait that shows codominance, both of the alleles in a _____________ individual contribute to the ______________.
Heterozygous individuals have _____ of the traits associated with their two alleles.
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22. What are the exceptions to complete dominance?
Unit 2 Lesson 4 Heredity
What are the exceptions to complete dominance?
____________ __________ __________is an example of codominance.
Three alleles, called A, B, and O, play a role in determining blood type.
A person with an A allele and a B allele has type AB blood.
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