Intro to Mendelian Genetics

Question 1

Genetic Traits

Answer 1

• particular version of an inherited characteristic
• eye colour, the shape of the leaf, colour of a flower or colour of a pea

Question 2

Trait Inheritance

Answer 2

• assumed that traits were a blend from the two parents
• not always the case
• Mendel was one of the first successful scientists to try and answer the question of how traits are inherited

Question 3

Mendel’s Pea Plants Experiments

Answer 3

• Mendel conducted a series of experiments with garden peas
• hosen because it reproduces quickly and it was easy to control which parents produce offspring
• Pea plants have both male and female reproductive organs
• can self ferlizie or cross ferilize

Question 4

True breeding plants

Answer 4

• reproduce by self-pollination or sexual reproduction with another true breeding plant the offspring produced will have the same trait
• purple flower true breeding plant will produce only purple flower offspring

Question 5

hybrid plants

Answer 5

• ## the offspring of two different true-breeding plants

Question 6

Crosses

Answer 6

• controlled expirements
• test how these traits were inherited through the use of true breeding and hybrid pea plants

Question 7

P to F1

Answer 7

• the male reproductive organs, the anther, were removed to prevent self-pollination
• crossed two true-breeding plants, called the parental (P) generation, that differ in only one of 7 hereditary traits he tested for
• hybrid offspring resulting from these crosses are called the filial (F1) generation

Question 8

F1 to F2

Answer 8

F2 generation: Self-pollination or pollution of 2 individuals of the F1 generation creates a new generation with mixed traits
- the result of a monohybrid cross

Question 9

Information after Mendel’s Pea Plants Experiments

Answer 9

• information about trait
• F1 generation always resulted in purple flowers even though they had one white and one purple flower parent
• did not fit the “blending” hypothesis
• one trait was masking the other
• F2 generation the white flower trait reappeared
• F2 generation in fact consistently had a 3:1

Question 10

First Law of Mendelian Inheritance

Answer 10

• Mendel concluded that traits must be passed on by discrete heredity units, which he called factors
• ## if factors are not expressed in an individual, they may still be passed on

Question 11

Dominant

Answer 11

The factor expressed in all F1 generations was called the

Question 12

recessive

Answer 12

The factor that remained, but was hidden in the F1 generation

Question 13

Alternate Forms of a Gene

Answer 13

• Each of your parents pass on a unique version of every gene on the chromosome present in the gamete
• alternate version of the genes= alleles
• If both of your alleles are identical you are homozygous
  If your two alleles are different you are heterozygous

Question 14

Alleles

Answer 14

• Dominant alleles are represented with a upper case letter
• dominance only refers to which gene is expressed if two different alleles are present (not stronger/coomon)
• Recessive Alleles are represented with a lower case letter

Question 15

Mendel’s Law of Segregation

Answer 15

• why the 3:1 ratio was present in the F2 generation
• For each characteristic (such as flower colour), an organism carries two factors (genes): one from each parent.
• Parent organisms donate only one copy of each gene in their gametes. During
  meiosis, the two copies of each gene separate, or segregate

Question 16

Genotype vs. Phenotype

Answer 16

The phenotype is trait of an individual which is expressed
i.e. a pea plant may have a purple flower or tall stem phenotype

The genotype is the individual genes (type of allies)
You cannot determine this in all cases by what it looks like
i.e. if you have purple flowers you are not certain if the genotype is Pp or PP