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The Work of Gregor Mendel

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The Work of Gregor Mendel Section 11 1 GENETICS The scientific study of heredity is called . Genetics Gregor Mendel s peas. b. When pollen fertilizes an egg cell ... – PowerPoint PPT presentation

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Title: The Work of Gregor Mendel


1
The Work of Gregor Mendel
  • Section 111

2
GENETICS
  • The scientific study of heredity is called .
  • Genetics

3
Gregor Mendels peas.
  • b. When pollen fertilizes an egg cell, a seed for
    a new plant is formed.
  • c. Pea plants normally reproduce by
    self-pollination.

4
  • What does it mean when pea plants are described
    as being true-breeding?
  • If the plants are allowed to self-pollinate,
    they would produce offspring identical to
    themselves.

5
Mendel the Monk
  • To perform his experiments, how did Mendel
    prevent pea flowers from self-pollinating and
    control their cross-pollination?
  • He cut away the pollen-bearing male parts of a
    flower and dusted that flower with pollen from
    another plant.

6
Traits
  • Traits
  • Specific characteristics that vary from one
    individual to another.

7
Hybrid
  • Hybrid
  • The offspring of crosses between parents with
    different traits.

8
Genes
  • Genes
  • Chemical factors that determine traits

9
Alleles
  • Alleles
  • The different forms of a gene

10
Principle of Dominance
  • State the principle of dominance.
  • Some alleles are dominant and others are
    recessive.

11
Dominance vs. Recessive
  • Is the following sentence true or false?
  • An organism with a recessive allele for
    aparticular form of a trait will always exhibit
    that form.
  • False

12
Dominance vs. Recessive
  • Circle the letters of the traits controlled by
    dominant alleles in Mendels pea plants.
  • a. tall
  • c. yellow

13
Segregation
14
Mendels Experiment
  • How did Mendel find out whether the recessive
    alleles were still present in theF1 plants?
  • He allowed the F1 plants to produce an F2
    generation by self-pollination.

15
Mendels Experiment
  • About one fourth of the F2 plants from Mendels
    F1 crosses showed the trait controlled by the
    allele.

16
Mendels Experiment
  • Circle the letter of each sentence that is true
    about Mendels explanation of the results from
    his F1 cross.
  • Mendel assumed that a dominant allele had masked
    the corresponding recessiveallele in the F1
    generation.
  • d. At some point, the allele for shortness was
    segregated, or separated, from the allelefor
    tallness.

17
Genetics
  • What are gametes?
  • They are the sex cells.

18
Segregation of Alleles
In the diagram above, the dominant allele is
represented by T and the recessive allele is
represented by t .
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