Mendels Law 1 Flashcards

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1
Q

Blending hypothesis

A

The factors that dictate hereditary traits can blend together from generation to generation. The blended traits are then passed to the next generation. Mendel refuted this viewpoint.

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2
Q

About Gregor Mendel

A

Born in 1822 in Czech Republic. Graduated and became a school teacher. He conducted breeding experiments on pea plants. His paper was published but was only recognized until 1900 when three scientists got similar results.

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3
Q

Garden pea

A

Pisum sativum. 14 chromosomes in a diploid cell. 7 homologous pairs.

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4
Q

Why did Mendel choose peas?

A

Peas are easy to cultivate, the grow rapidly, produce many offspring, and vary in traits.

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5
Q

Gene def

A

An inherited factor that helps determine a characteristic

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6
Q

Allele def

A

One of two or more alternative forms of a gene

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7
Q

Locus def

A

Specific place on a chromosome occupied by an allele

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8
Q

Genotype def

A

Set of alleles possessed by an individual organism

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9
Q

Heterozygote def

A

An individual organism possessing two different alleles at a locus

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10
Q

Homozygote def

A

An individual organism possessing two of the same alleles as a locus

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11
Q

Phenotype or trait def

A

The appearance of a characteristic

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12
Q

Characteristic def

A

An attribute or feature possessed by an organism

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13
Q

Difference between genes and alleles

A

Genes are DNA sections that code for specific proteins or functional RNA. Alleles are alternate forms of a gene at the same locus, leading to diverse traits

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14
Q

Genotype def

A

The set of genes that it carries

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15
Q

Phenotype def

A

All of its observable characteristics

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16
Q

Mendels work

A

O generation: crossed RR and rr to for only Rr
F1 generation: Mendel self-fertilized the F1 Rr to for F2
F2 generation: 3:1 ration of round to wrinkles. Genotypes RR Rr Rr rr

17
Q

Revelations from monohybrid crosses

A
  1. F1 generation show only phenotype of one parent, they must inherit genetic factors from both because both phenotypes are shown in F2. Each plant must therefore possess two genetic factors encoding a characteristic.
  2. Mendel found that the two alleles in each plant separate when gametes are formed, and one allele goes in each gamete.
  3. When dominant and recessive alleles are present together, the recessive is masked.
  4. The alleles of an individual plant separate with equal probability into the gametes.
18
Q

Mendels first law- the principle of segregation

A
  1. Each individual organism possesses two alleles for each characteristic. (Before meiosis)
  2. The two alleles segregate when gametes are formed and one goes into each gamete. (Anaphase 1)
  3. The alleles separate in equal proportions (anaphase 1)
    Chromosome segregation is the basis of the principle of segregation
19
Q

Round or wrinkled peas?

A

The locus that determines whether a pea is round or wrinkled is a sequence of DNA found on chromosomes 5 that encodes a protein called SBE1.
The dominants allele codes for a normal, functional form of the SBE1 enzyme. This enzyme converts a linear form of starch into a highly branched form.

The recessive r allele is a different DNA sequence that contains a mutation, and encodes an inactive form of the enzyme that doesn’t produce the branched form of starch and leads to the accumulation of sucrose within rr pea.