Gregor Mendel's theory

Question 1

what was Aristotle’s theory?

Answer 1

pangenesis (widely accepted)

Question 2

what did he do at his time at the monastery?

Answer 2

conducted a series of experiments over 8 years using common pea plants

Question 3

when was his work recognized?

Answer 3

not until years after his death

Question 4

why did he use pea plants?

Answer 4

easy to grow
well defined characteristics (easy to see)
each flower has both female and male reproductive structures
easy to mate (normally self-pollinate but can easily cross-pollinate)
produce large number of offspring in short period of time

Question 5

why did Mendel use pea plants?

Answer 5

easy to grow
well defined characteristics (easy to see)
each flower has both female and male reproductive structures
easy to mate (normally self-pollinate but can easily cross-pollinate)
produce large number of offspring in short period of time

Question 6

what were 7 distinct traits studied?

Answer 6

seed shape, seed colour, flower colour, flower position, pod colour, pod shape, plant height

Question 7

why was he so successful?

Answer 7

used an appropriate organism (by chance)
designed and performed experiments scientifically (with proper controls)
analyzed data properly (applied mathematics)

Question 8

how did Mendel set up his experiments?

Answer 8

produced purebred plants for the parent generation to eliminate risk of hidden background characteristics

Question 9

setting up his experiments

how did he eliminate risk of hidden background characteristics?

Answer 9

produced purebred plants for the parent generation

Question 10

setting up his experiments

how did he study characteristics?

Answer 10

studied 1 pair of characteristics at one time, all others were controlled (kept the same)

Question 11

setting up his experiments

how did he prevent self-pollination?

Answer 11

stamens were removed from one of the parent plants

Question 12

setting up his experiments

how did he cross-pollinate?

Answer 12

selected and transferred pollen from one plant’s flower to another

Question 13

setting up his experiments

how did Mendel cross-pollinate?

Answer 13

selected and transferred pollen from one plant’s flower to another

Question 14

what was his first experiment?

Answer 14

plant height

Question 15

how did he conduct the height experiment?

Answer 15

cross-fertilized two purebred pea plants that showed short and tall plant heights, respectively
Parent (P) generation

Question 16

what were the results from the first height experiment?

Answer 16

first Filial (F1) generation offspring were all tall
therefore 100% tall (phenotype)

Question 17

what happened after repeating the height experiment while examining other pairs of traits?

Answer 17

he observed that one trait was always dominant over the other

Question 18

what was the principle of dominance (the conclusion)?

Answer 18

when an organism is a hybrid (crossbreed) for a pair of contrasting traits, it will show only the dominant trait

Question 19

what was his second experiment?

Answer 19

hybrid tall plants from F1 generation in 1st experiment self-pollinated

Question 20

what were the results from the second experiment?

Answer 20

second Filial (F2) generation obtained were mostly tall but some were short
75% tall, 25% short (3:1 ratio)

Question 21

what happened after repeating the second experiment while examining other pairs of traits?

Answer 21

he observed the same ratio of 3:1 (called the Mendelian ratio)

Question 22

what are alleles?

Answer 22

alternate forms of a gene

Question 23

how many genes does an organism have for each inherited trait?

Answer 23

two genes (alleles)
one allele is inherited from each parent

Question 24

how many alleles does a sperm or egg carry for each inherited trait and why?

Answer 24

only one allele because allele pairs segregate from each other during the production of gametes by meiosis

Question 25

what happens when two alleles of a pair are different?

Answer 25

one is fully expressed and the other is completely masked

Question 26

what is the fully expressed allele called?

Answer 26

dominant

Question 27

what is the completely masked allele called?

Answer 27

recessive