Chapter 5 (Excluding 5.3) Flashcards

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1
Q

What plant did Gregor Mendel use for his experiments?

A

He choose Pea plants (Pisum Sativum)

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2
Q

Why was Gregor Mendel’s choice of pea plants a good one?

A
  • Readily available
  • Short generation time
  • Showed many traits
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3
Q

What is a trait?

A

A specific characteristic or feature exhibited by an organism (such as flower colour of a plant)

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4
Q

What does it mean to self-fertilize?

A

The same plant provides the male and female gamete

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5
Q

What does true breeding/pure breeding mean?

A

An organism that exhibits the same traits generation after generation

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6
Q

How did Gregor Mendel control his pea plant experiments?

A

He selectively fertilized a female gamete with a specific male gamete in a process called a cross

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7
Q

What is a Cross also referred as?

A

Cross-pollination

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8
Q

Describe the steps in Gregor Mendel’s experiments

A
  1. Used pure breeding ( genetically identical) lines of peas and looked at 7 different traits
  2. Crosses a pure breeding plant with a plant of the opposite trait (white x purple). Called this P generation
  3. Recorded data on offspring called First Filial (F1)
  4. Self pollinated F1
  5. Recorded data on offspring; Second Filial (F2)
  6. Always 3:1 ratio
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9
Q

What is a Monohybrid cross?

A

A cross of 2 individuals that differ by one trait

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10
Q

What is the Mendelian ratio?

A

The ratio of 3:1 in the F2 generation

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11
Q

What is the Law of Segregation?

A

Says that traits are determined by pairs of alleles that segregate during meiosis so that each gamete receives one allele

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12
Q

What are alleles?

A

Different forms of a gene and diploid organisms have 2 alleles for each trait

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13
Q

What else does the Law of segregation say about pairs of pairs of alleles?

A

One allele is dominant, while another is said to be recessive

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14
Q

What does Dominant mean?

A

The form of a trait that always appears when an individual has an allele for it (only one is needed to show trait)

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15
Q

What does Recessive mean?

A

The form of a trait that only appears when an individual has 2 alleles for it

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16
Q

What else does the Law of Segregation say?

A
  • Inherited traits are determined by 2 alleles of a gene
  • These 2 alleles segregate into each gamete of the parents during meiosis
  • Each gamete contains one of the alleles
  • When fertilized, each offspring has one allele from each parent (total of 2)
  • The trait expressed will depend on they inherit dominant or recessive alleles
17
Q

What does expression of the recessive trait require?

A

An individual needs to have 2 alleles for the trait (only recessive)

18
Q

What is a genotype?

A

The combination of alleles in an organization (Ex. Yy, yy, YY)

19
Q

What is a Phenotype?

A

The physical and physiological traits of an organism. The expression of a genotype is called the phenotype

20
Q

What does it mean to be Homozygous for a trait?

A

An individual has 2 identical alleles for that trait (Ex. YY or yy)

21
Q

What does it mean to be Heterozygous for a trait?

A

An individual has 2 different alleles for a gene (Ex. Yy)

22
Q

What are used to analyze the results of crosses?

A

Punnett Squares (Made by Reginald Punnett)

23
Q

What do Punnett Squares do?

A

Uses Mendel’s Law of Segregation to show all possible offspring that could be formed from the gametes of the parents

24
Q

What do the 4 squares in a Punnett Square represent?

A

They represent the 4 possible combinations and the chance of each of them occurring (each square represents 1/4 or 25%)

25
Q

What is a Dihybrid Cross?

A

A cross of 2 individuals that differ in 2 traits due to 2 different genes, each consisting of non-identical alleles

26
Q

What were Mendel’s results when he conducted his Dihybrid cross experiment?

A

He always received the same ratio of 9:3:3:1

27
Q

What is the Law of Independent Assortment?

A

States that during gamete formation, alleles for one gene segregate or assort independently of the alleles for other genes during gamete formation

28
Q

What theory did Sutton propose?

A

He proposed the Chromosome theory of inheritance

29
Q

What is the chromosome theory of inheritance?

A

Traits are determined by genes inherited through movement of chromosomes during meiosis

30
Q

What did Sutton realize were related to Mendel’s pea plant results?

A

Chromosomes

31
Q

What does the Chromosome theory of inheritance state?

A
  1. Genes are carried on chromosomes

2. Chromosomes provide basis for law of segregation and law of independent assortment

32
Q

Who developed the theory of inheritance?

A

Gregor Mendel