Mendels Law 1

Question 1

Blending hypothesis

Answer 1

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.

Question 2

About Gregor Mendel

Answer 2

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.

Question 3

Garden pea

Answer 3

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

Question 4

Why did Mendel choose peas?

Answer 4

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

Question 5

Gene def

Answer 5

An inherited factor that helps determine a characteristic

Question 6

Allele def

Answer 6

One of two or more alternative forms of a gene

Question 7

Locus def

Answer 7

Specific place on a chromosome occupied by an allele

Question 8

Genotype def

Answer 8

Set of alleles possessed by an individual organism

Question 9

Heterozygote def

Answer 9

An individual organism possessing two different alleles at a locus

Question 10

Homozygote def

Answer 10

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

Question 11

Phenotype or trait def

Answer 11

The appearance of a characteristic

Question 12

Characteristic def

Answer 12

An attribute or feature possessed by an organism

Question 13

Difference between genes and alleles

Answer 13

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

Question 14

Genotype def

Answer 14

The set of genes that it carries

Question 15

Phenotype def

Answer 15

All of its observable characteristics

Question 16

Mendels work

Answer 16

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

Question 17

Revelations from monohybrid crosses

Answer 17

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.

Question 18

Mendels first law- the principle of segregation

Answer 18

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

Question 19

Round or wrinkled peas?

Answer 19

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.