Hand in W.S.

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Class Topics
Title Biology 1/29/07
Objectives

• To learning about Mendelian genetics.

• Hand in W.S. The Puzzle of Heredity before the
  bell rings please
• Chapter 7 Test
• Chapter 8 Mendelian Genetics
• Mendels laws
• Terminology
• Genetics Problems
• The most effective way to cope with change is to
  help create it.
• L.W. Lynett

Thursday, July 30, 2015 615 PM
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Class Assignments
By When
What

• Read 166-170 1/29/07
• W.S. The Puzzle of Heredity 1/29/07
• Chapter 8 Quiz 1 1/31/07
• Genetics Problems 2/2/07
• Due this class period
• Due next class period
• Due in the future

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Grade Sheet
2A p. 157 (5 pts.)
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Chapter 7 Test

• You will get your test back and be given 20
  minutes to adjust any answers.
• Hand in test when completed
• Begin working on the Math Lab (in your notebook)
  on page 165

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Math Labp. 165

• Calculating Mendels ratios
• Copy the table
• Calculate the ratio
• State the ratio in words and then as a fraction
• Answer the final question

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Mendels Theory

• Historical perspective
• Heredity was thought of as a blending of the two
  parents
• Mendel determined that there were two separate
  heritable factors for each trait
• Factors are called alleles (book says genes)

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Mendels hypothesis

• 1. For each inherited trait, an individual has
  two copies of the gene one from each parent.
• 2. There are different versions of genes.
• Alleles
• Receive one from each parent

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Mendels hypothesis

• 3. Dominant allele
• Can mask the presence of another allele
• Expressed whenever present
• Represented by a capital letter
• recessive allele
• Can be masked by the presence of a dominant
  allele
• Only expressed when contrasting allele is not
  present
• Represented by a lowercase letter (same letter as
  dominant)

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Laws of heredity

• Law of segregation
• The two alleles for a trait separate when gametes
  are formed
• Law of independent assortment
• Different genes separate independently from one
  another during gamete formation
• Assuming theyre on different chromosomes
• Used in a dihydrid cross

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Genotype

• The alleles for a trait
• Consider the trait Seed color
• Dominant - Yellow seeds (Y)
• Recessive - Green seeds (y)
• Homozygous dominant (true breeding)
• YY
• Heterozygous (hybrid)
• Yy
• Mixed pair of alleles
• Homozygous recessive (true breeding)
• yy

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Phenotype

• The physical appearance of a trait
• Tall or dwarf plants
• Round or wrinkled seeds
• Yellow or green seeds

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Mendels Cross

• Cross a purebreeding smooth pod shape with a
  pinched pod shape
• P
• F1
• Pheno
• Geno
• F2
• Pheno
• Geno

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Practice problem

• Using the trait of flower position, cross a
  hybrid with a purebreeding terminal.
• P ___ x ___
• F1
• Pheno
• Geno

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Practice problem

• Tall is dominant over short cross a homozygous
  recessive with a heterozygous
• P ___ x ___
• F1
• Pheno
• Geno

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Chapter 8 Quiz 1 Review

• Matching
• Alleles, Dominant, Gene, Genetics, Genotype,
  Heredity, Homozygous, Heterozygous, Hybrid,
  Independent assortment, Phenotype, Recessive,
  Segregation,Trait
• Mendels traits
• Mendels success
• Genetic symbols
• Mendels cross