Mendel

Question 1

why did Mendel choose garden peas

Answer 1

1. from previous investigators, he knew he could expect to observe segregation of traits among the offspring.
2. a large number of pure varieties of peas were available
3. pea plants are small and easy to grow, and have a relatively short generation time.
4. both female and male sexual organs are enclosed within each pea flower and gametes produced can undergo self-fertilization.

Question 2

what are the three stages of Mendel’s experiment

Answer 2

1. allowing plants of a given variety to self-cross for multiple generations to ensure the cases he was studying were true-breeding.
2. performed crosses between true-breeding varieties, and reciprocal crosses.
3. allowed the hybrid offspring produced by these crosses to self-fertilize for several generations. he counted the numbers of offspring exhibiting each trait in each succeeding generation.

Question 3

monohybrid cross

Answer 3

a cross that follows only two variations on a single trait. ex: white and purple coloured flowers.

Question 4

F1 generation - monohybrid cross

Answer 4

first filial generation of offspring from the parent cross. in crosses between pure-breeding parents, dominant trait is expressed, and recessive trait is not expressed until F2 generation.

Question 5

F2 generation - monohybrid cross

Answer 5

the Mendelian ratio is expressed as a 3:1 ratio, where 3 is dominant, and 1 is recessive.

Question 6

F2 generation and true breeding - monohybrid cross

Answer 6

by allowing the F2 generation to self-fertilize, Mendel found from the offspring that the ratio of F2 plants was 1 pure breeding dominant: 2 not pure breeding dominant: 1 pure breeding recessive. (1:2:1).

Question 7

Mendel’s Principle of Segregation

Answer 7

the two alleles for a gene segregate during gamete formation and are rejoined at random, one from each parent, during fertilization.

Question 8

dihybrid cross

Answer 8

a single genetic cross involving two different traits, such as flower colour and plant height.

Question 9

F1 generation - dihybrid cross

Answer 9

heterozygous F1 individuals, displaying the same phenotype, and the same genotype. RR YY + rr yy = Rr Yy, displays 2/4 traits

Question 10

F2 generation - dihybrid cross

Answer 10

exhibits a 9:3:3:1 ratio

Question 11

Mendel’s Principle of Independent Assortment

Answer 11

in a dihybrid cross, the alleles of each gene assort independently.