Chapter 14 Mendel and the Gene Idea Flashcards
(45 cards)
What are the two laws of inheritance Mendel discovered?
The law of segregation
The law of independent assortment
The pea plants he studied had many varieties with distinct features called _____________ (such as flower color)
Variants of these (such as purple or white flowers) are called ________
Characters
Traits
What is true breeding?
Plants that produce offspring of the same variety when they self-pollinate
*every generation is the same
In a typical experiment mental would mate two contrasting, true breeding varieties, this process is called…..
When only a single factor is crossed and allows for variation in one character it is called….
Hybridization
Monohybrid
True breeding parents is the _____ generation
P
What did Mendel see when he crossed contesting true breeding pea plants?
What did he see when he crossed those F1 plants?
All the F1 hybrids were the dominate trait (purple)
3 to 1 ratio
What Mendel called a “___________” we now call a gene
Heritable factor
What is the first concept of Mendel’s model?
Alternative versions of genes account for variations in inherited characters
This called an allele
What is the second concept of Mendel’s model?
For each character, an organism inherits two alleles, one from each parent
*He made this deduction without knowing about chromosomes
What is the third concept of Mendel’s model?
If the two alleles at a locus differ, then one, the dominate allele, determines the appearance and the other has no noticeable effect on appearance
What is the forth concept of Mendel’s model?
What’s it also known as?
AKA the law of segregation
Two alleles for a heritable character separate during gamete formation and end up in different gametes
Mendel’s ______________ model accounts for the 3:1 ratio he observed in the F2 generation
Segregation
Only ____________ are true breeding
Homozygotes
Phenotype vs. genotype?
Physical appearance
Genetic makeup
How can we tell the genotype of an individual with a dominant phenotype?
Carry out a cross test
How is a cross test done?
Breed the mystery individual with a homozygous resssive individual
If any are recessive phenotype, then the mystery parent must be heterozygous
How did Mendel identify this second law of inheritance (independent assortment)?
By following two characters at the same time
These are called dihybrids
A cross between F1 dihybrids, can determine weather two characters are transmitted to offspring as a package or independently
What is this cross called?
Dihybrid cross
What ratio do you get when you cross two heterozygous traits?
9:3:3:1
Using a dihybrid cross Mendel declines the law of…….
Independent assortment
This law states that each pair of alleles segregates independently of each other pair of alleles during gamete formation
This is only when they are on different chromosomes***
Law of segregation
The law of segregation only applies to….
Genes on different, non homologous chromosomes or those far apart on the same chromosome
Genes located near each other on the same chromosome tend to be …..
Inherited together
When they are different chromosomes they sort independently
Mendel’s laws of segregation and independent assortment reflect the rules of……
Probability
