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Biology 11E Genetics Name ________________________

Reference Chapter 14

3.A.3 The chromosomal basis of inheritance provides an understanding of the pattern of passage (transmission) of genes from parent to offspring

14.1, 14.2, 14.3, 14.4 • Sickle cell anemia • Tay-Sachs disease • Huntington’s disease • X-linked color blindness • Trisomy 21/Down syndrome • Klinefelter’s syndrome • Reproduction issues • Civic issues such as ownership of genetic information, privacy, historical contexts, etc.

4.C.2: Environmental factors influence the expression of the genotype in an organism.

14.3 • Height and weight in humans • Flower color based on soil pH • Seasonal fur color in arctic animals • Sex determination in reptiles • Density of plant hairs as a function of herbivory • Effect of adding lactose to a Lac + bacterial culture • Effect of increased UV on melanin production in animals • Presence of the opposite mating type on pheromones production in yeast and other fungi • Darker fur in cooler regions of the body in certain mammal species • Alterations in timing of flowering due to climate changes

C.4: The diversity of species within an ecosystem may influence the stability of the ecosystem.

14.3 23.2 54.2 56.1

No illustrative examples listed in the Curriculum Framework.

Biology11AP Genetics notes

1. Who is the most famous scientist in the field of genetics?

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2. What type of organism did he study to learn about inheritance?

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3. What was the first major observation that Mendel made when he crossed two strains of pure-breeding peas and observed a particular characteristic that showed two traits, such as purple and white flowers?

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*Use the Word study tools on the textbook website for chapter 14 to differentiate between:

a) A character and a trait

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b) True breeding and hybridization

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c) P generation and F1 or F2 generation.

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d) Dominant and recessive alleles

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4. Did Mendel observe the same phenomenon when he looked at other pea characteristics

besides flower colour? ____________________________________________________

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How did Mendel describe the trait that showed up in the F1 generation?

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How did he describe the trait that disappeared in the F1 generation and reappeared in the

F2 generation? ___________________________________________________________


See Campbell’s activity 14.1 Monohybrid cross

5. This box summarizes Mendel’s pea-breeding experiments:

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Alternative versions of a gene are called

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Where the gene is found on a particular

chromosome is called the

______________ for that gene.

6. What are the four main ideas that make up Mendel’s model to explain inheritance of a


single character? (This is also called a single-factor cross. When the F1 generation are crossed, it is referred to as a monohybrid cross.)

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This box illustrates

Mendel’s Law of

Segregation.

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7. Be sure that you understand the following genetics vocabulary:

Homozygous: _________________________________________________________________

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Heterozygous: _________________________________________________________________

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Phenotype: ____________________________________________________________________

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Genotype: ____________________________________________________________________

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Concept 14.2:


The laws of probability govern Mendelian inheritance

Campbell’s Activity 14.2 – Gregor’s Garden

8. The Test Cross

How can we use a test cross to determine the genotype of an organism showing the dominant phenotype? (See Campbell’s activity 14A2, 3)

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9. Mendel’s observations of two characteristics at the same time, led to his Law of Independent Assortment? (Campbell’s Activity 14.1: Dihybrid Cross)

He started by asking the question: Will two different characteristics be inherited together as a unit, or independently of each other?

The diagram below shows the predicted results from the two possible hypotheses:

Which of the two hypotheses was supported by Mendel’s data?

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Do Concept Check 14.1 p 269


10. Alleles segregate into gametes following rules of probability

The expected proportions of offspring genotypes can be calculated following the rules of probability:

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How can we use the two rules of probability to solve more complex genetics problems?


For example:

Solve this problem: In the trihybrid cross, PpYyRr × Ppyyrr, what are the chances that an

individual will exhibit at least two recessive traits?

The first step is to list the genotypes that would result in at least two recessive traits:

The second step is to figure out the probability of each genotype, using the law of multiplication:

The third step is to add together all the different probabilities, using the law of addition:

Concept Check 14.2 p 271


Degrees of Dominance11. What is Incomplete Dominance?

Activity 14.3: Incomplete Dominance

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What ratio of phenotypes is expected in the F2 generation?

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12. What is Codominance?

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Blood Types are a good example of Multiple Alleles AND Codominance:

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In epistasis, a gene at one locus alters the phenotypic expression of a gene at a second locus:


In polygenic inheritance, more than one gene contributes to the inheritance of a character. For example, in the inheritance of skin colour, at least 3 different genes are involved. Which individual inherits the darkest skin? _________________The lightest? __________________


13. Pleiotrophy the ability of genes to affect an organism in more than one way. eg sickle-cell allele


Gene expression can depend on environmental factors. For example, in the hydrangea, the colour of the flowers depends on the acidity of the soil:

Concept Check 14.3 p 275


Many human characters follow Mendelian patterns of inheritance. Widow’s peak and attached earlobes are two examples.

Pedigree Analysis - studying the inheritance of human genetic traits within a family

Note: the allele for widow’s peak is dominant over the allele for no widow’s peak; the allele for free earlobe is dominant over the allele for attached earlobe. ______________________________________________________________________________

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Recessive alleles

Albinism

Describe two other recessively inherited disorders. p.278


People who are heterozygous for a recessive autosomal mutation are called

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What is a problem associated with the mating of close relatives? _________________________

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Dominantly inherited disorders.

Give an example of a human genetic disorder that is caused by a dominant autosomal mutation:

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15. Fetal Diagnosis is used to determine whether the fetus carries a genetic disorder:

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Do Concept Check 14.4

Complete all genetics problems pp. 284 to 285 and

Scientific inquiry p.285


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