Lecture 3 Flashcards
What were Mendel’s peas?
Highly in-bred
What does the flower structure promote?
Self-fertilization making them pure-bred (want every gene to be homozygous)
What were Mendel’s experiments designed for?
So that he could study one trait at a time
Gene
An inherited factor (encoded in the DNA) that helps determine a characteristic
Allele
One of two or more alternative forms of a gene (dominant/recessive)
Locus
Specific place on a chromosome occupied by an allele (address on a chromosome)
Genotype
Set of alleles possessed by an individual organism (at a specific locus)
Heterozygote
An individual organism possessing two different alleles at a locus
Homozygote
An individual organism possessing two of the same alleles at a locus
Phenotype or trait
The appearance or manifestation of a characteristic (what it actually looks like)
Characteristic
An attribute or feature possessed by an organism
What do upper case letters refer to?
Dominant (expressed factor) allele
What do lower case letters refer to?
Recessive (latent factor) allele
What is the allelic combination called?
The genotype
What is the physical appearance called?
The phenotype
What do genes exist in different versions of?
Alleles
What do different alleles for a particular gene occupy?
The same locus on homologous chromosomes
What did Mendel do to cross different varieties of peas?
Removed the anthers from flowers to prevent self-fertilization
Dusted the stigma with pollen from a different plan
The pollen fertilized into ova which developed into seeds, which grew into plants
What is P?
Parental Generation
What is F1?
First Filial Generation
What is F2?
Second Filial Generation
What was the conclusion of Mendel’s findings?
The traits of parents do not blend
What ratio did Mendel’s findings produce?
3:1 Ratio
What are the observations of Mendel’s first law of segregation?
- Each individual organism possesses two alleles encoding a trait
- Alleles separate when gametes are formed
- Alleles separate in equal proportions
