Genetics Flashcards
Hereditary
the passing of traits from parent to offspring
Genetics
branch of biology that studies the ways in which hereditary info is passed from parents to offspring
Gregor Mendel
monk who began the study of hereditary by carrying out experiments using pea plants
Why were peas useful to study?
Several traits of the peas only existed in two forms, mating can be easily controlled, and peas grow easily/mature fast/produce many offspring
Why can pea mating be easily controlled?
The female and male parts are enclosed within the same flower
How do flowers (peas) fertilize?
Either self fertilize or cross pollination
what is cross pollination?
transferring the pollen from one plant to another flower on a different plant
monohybrid cross
studies inheritance of only one pair of contrasting traits
What did Mendel begin his experiments by using?
a monohybrid cross
True breeding plant
Only produces offspring of the same type
What did Mendel do to ensure that each plant was true breeding?
He allowed each plant to self pollinate for several generations
What is the P generation?
The parental generation, or the true breeding plants that produce more of themselves
What was the F1 generation?
The first filial generation
What did the F1 generation result from?
Cross pollination of the two, different, P generation plants (by Mendel)
What happened to the F1 generation?
They were allowed to self pollinate, resulting in the F2 generation
What were Mendel’s results with the F1 generation?
They all had only one trait. In this example, all the flowers were purple-the white trait had disappeared.
What were Mendel’s results with the F2 generation?
The missing trait had reappeared. (705 purple:224 white) (3.15:1)
What did Mendel’s experiment prove instead?
Peas (and humans) have separate heritable factors for each trait, one from each parent.
What did Mendel disprove with his experiments?
Scientific belief that an offspring’s traits were a blend of the parents.
What are the separate heritable factors for each trait called?
Genes.
How many copies of a gene does an individual have, and where do they get them according to Mendel’s Hypotheses?
An individual has two copies of every gene, one from each parent
What are alleles?
Alternative versions/copies of the same gene
What is the example of an allele in relation to Mendel’s experiment?
Purple vs white flowers
What happens when there are two different alleles in an organism?
Only one will be expressed
What is a dominant allele?
Observable/expressed
What is a recessive allele?
Trait that isn’t expressed in presence of dominant
Which alleles (dominant v. recessive) were present in Mendel’s experiments?
One dominant, one recessive
Did Mendel’s hypotheses include alleles and dominance?
Yes
Gametes formed by meiosis have how many alleles for each trait? Was this mentioned in Mendel’s experiments?
Only one, and yes
What happens to the alleles when gametes unite in fertilization?
Each gamete contributes one allele, their allele
How are dominant alleles represented?
Write the first letter of trait as capital