Genetics: Chapter 2

Front 1

Define genes

Back 1

a DNA sequence that can determine a trait (codes for a protein).

Front 2

Allele

Back 2

An alternate form of a gene. Same gene but different DNA sequence.

Front 3

Dominant Allele

Back 3

An allele capable of masking a recessive trait.

Front 4

Recessive Allele

Back 4

An allele that exhibits a recessive trait if a dominant corresponding allele is not present.

Front 5

Define blended hypothesis

Back 5

States that a cross took on aspects of both parents. Obvious exceptions led Mendel to question this hypothesis.

Front 6

What is the plant that Mendel use to begin his early genetic tests?

Back 6

Garden peas Pisum Sativum

Front 7

Why did Mendel use the Pisum Sativum ?

Back 7

1. Very easy to selectively breed. They could be selfed for several generations to develop "true-breeding" lines
2. Very little genetic variations.
3. 7 different characteristics were chosen to study. These traits were encoded on genes either on different chromosomes or far apart on the same chromosome.
4. Dominant vs. recessive traits were easily distinguishable.

Front 8

Artificial Selection

Back 8

A purposeful control over mating by choice of parents for the next generation.

Front 9

Why did Mendel use the pea plant, Pisum sativum ?

Back 9

1. They were easy to selectively breed with several generations produced in short period of time. And he could cross fertilize them by brushing pollen from one plant to another.
2. Very little genetic variations so it's easier to observe.
3. Could be selfed for several generations to develop true breeding line. The offspring carry parental traits that remain constant from generation to generation.
4. Crosses could be controlled. Reciprocal crosses used to reverse the traits of male and female parents.
5. He used seven traits encoded on genes to study.

Front 10

How was Mendel's work different from his predecessors ?

Back 10

1. He questioned the blended hypothesis. That some traits are not passed down from one parent more than the other.
2. He used the pea plant, Pisum sativum.
3. Used artificial selection in his work to study observable traits.
4. He worked with large number of plants and used numerical analysis to make predictions. He used dominant vs. recessive conditions so that its easily distinguishable.