Intro to Mendelian Genetics (lesson five)

Question 1

Genetic Traits

Answer 1

traits inherited from your family

Question 2

Mendel and garden peas

Answer 2

• Mendel conducted a series of experiments with garden peas
• This species was chosen because it reproduces quickly and it was easy to control which parents produce offspring
• Pea plants have both male and female reproductive organs
• This means the peas can self-fertilize (self-pollinate) or cross-fertilize (mate with others)

Question 3

true breeding plants

Answer 3

Some plants, including garden peas, can be true-breeding plants
- meaning that when these plants reproduce by self-pollination or sexual reproduction with another true breeding plant, the offspring produced will have the same trait
- i.e. purple flower true breeding plant will produce only purple flower offspring

Question 4

hybrid plants

Answer 4

Some plants, including garden peas, can be hybrid plants
- These plants are the offspring of two different true-breeding plants
- Mendel did controlled experiments, called crosses, to test how these traits were inherited through the use of true breeding and hybrid pea plants

Question 5

Mendel’s Pea Plants Experiments

Answer 5

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

Question 6

F2 generation

Answer 6

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

Question 7

First Law of Mendelian Inheritance

Answer 7

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

Question 8

the dominant factor

Answer 8

The factor expressed in all F1 generations was called the dominant factor

Question 9

the recessive factor

Answer 9

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

Question 10

Alternate Forms of a Gene

Answer 10

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

Question 11

Mendel’s Law of Segregation

Answer 11

• Each organism carries two factors, now known as genes, one from each parent for each characteristic
• Parent organisms donate only one copy of each gene in their gametes
• This was long before we had any knowledge of the chromosome

Question 12

Genotype

Answer 12

The genotype is the individual genes an individual presents
- 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

Question 13

Phenotype

Answer 13

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