9.1.1 Heredity: The Story of Gregor Mendel Flashcards Preview

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Flashcards in 9.1.1 Heredity: The Story of Gregor Mendel Deck (18)
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1
Q

note

A
  • Until the 1900s, many scientists believed that traits in offspring were a blend of parental traits.
    • In the 1800s, Gregor Mendel discovered the fundamental mechanism by which traits are inherited.
    • Darwin’s theory of evolution by natural selection lacked a mechanism to explain how traits are inherited.
2
Q

Gregor Mendel

A
  • In the 1800s, Gregor Mendel discovered the fundamental mechanism by which traits are inherited
  • Based on the work of Gregor Mendel and modern geneticists, we now understand the mechanisms underlying inheritance—the way traits are passed on from generation to generation.
  • Review: DNA makes RNA, which makes protein.
  • In the 1800s, the mechanism by which traits are inherited was a subject of great controversy.
  • A chronology of Gregor Mendel’s life is illustrated to the left. In 1853 Mendel returned to the monastery after attending the University of Vienna to study science and statistics. In 1857 he began performing experiments on pea plants to study inheritance
  • In 1865 Mendel gave a public talk about his discoveries. His paper was published and sent to 120 libraries and 40 scientists, but no one understood the magnitude of his findings.
  • Charles Darwin’s theory of evolution by natural selection lacked a mechanism to explain how traits could have variation yet display stability across generations. Darwin did not realize that Mendel’s findings provided the missing piece of the puzzle.
3
Q

blending inheritance

A
  • The theory of blending inheritance was put forth in the
    1800s. According to this theory, traits present in the parents mixed together like paint to produce a new combination in the offspring.
  • The theory was based on the observation that offspring can have some of the characteristics of the mother or father but typically are not identical to either one.
4
Q

Josef Kohlreuter

A
  • Some of the first genetic experiments were performed on plants. Horticulture, the science of growing flowers, provided data as to how traits are inherited.
  • Josef Köhlreuter conducted formal plant-breeding
    experiments in the 1700s. He first crossed red, male flowers with white, female flowers. He also made the reciprocal cross of white, male flowers with red, female flowers. Red flowers were produced in both crosses. He concluded that males and females both contribute to the appearance of traits.
5
Q

In the Origin of the Species, Charles Darwin was able to fully describe the mechanism of evolution because he understood Gregor Mendel’s paper on inheritance.

A
  • false
6
Q

Which of the following sums up Josef Köhlreuter’s main contribution to the field of genetics?

A
  • He determined that both the male and female equally contribute to the appearance of traits in the offspring
7
Q

Which of the following statements is the most accurate?

A
  • DNA makes RNA, which makes protein
8
Q

How was Mendel able to manipulate pea plants to determine the mechanism of inheritance?

A
  • Pea flower pollen is contained in the anther and can be removed from the plant and used to fertilize another flower’s ovules contained in the carpel
9
Q

True or false?
An example of horticulture is crossing one plant that grows quickly with another plant that is pest resistant in the laboratory in order to produce offspring that both grow quickly and are pest resistant.

A
  • true
10
Q

Up until the 1900’s many scientists believed that traits in offspring were a blend of parental traits. Why is this idea incorrect?

A
  • The idea of blending of traits would suggest that if a white flower and a red flower produce a purple flower then all the flowers in the world should be purple. In fact, we observe many different colors of flowers.
  • The idea of blending of traits suggests that if a purple flower is crossed with another purple flower all the offspring should be purple flowers. In fact, crossing purple flowers may produce red, white or purple offspring.
  • The idea of blending of traits makes no sense when we consider the great biological diversity on our planet.
11
Q

What is plant hybridization?

A
  • The process of crossing two genetically different parent plants to produce offspring with traits of both parents
12
Q

Gregor Mendel’s study of what subject was crucial in his ability to analyze his hybridization experiments?

A
  • Statistics
13
Q

Which of the following is an example of a reciprocal cross?

A

(yellow male) × (green female)

green male) × (yellow female

14
Q

What is inheritance?

A
  • Inheritance is the way that genetically based traits are passed on from generation to generation
15
Q

What was Joseph Kölreuter’s contribution to our understanding of heredity?

A
  • Kölreuter found that reciprocal crosses produce identical offspring.
16
Q

Put the following events in Mendel’s life in chronological order.

  1. Mendel enters monastery.
  2. Mendel studies statistics at the University of Vienna.
  3. Mendel put in charge of the monastery gardens.
  4. Mendel fails exam to become teacher.
  5. Mendel gives talk describing his research.
A
  • 1, 4, 2, 3, 5
17
Q

True or false?
Mendel’s work filled such a large void in the understanding of genetics that it was no wonder it was hailed as a masterpiece when it was published in 1866.

A
  • false
18
Q

What is the best explanation as to why the theory of “blending inheritance” was abandoned?

A
  • It could not explain how variation in individuals was maintained over time

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