Study Guide Chapter 3 Flashcards
What did Gregor Mendel do?
Mendel observed that traits often skip generations. Based on this observation, Mendel created an experiment to explain how that happens
who is Gregor Mendel and what he is known for
He was a scientist who discovered the principles of heredity through his his study of pea plants. Because of his discoveries, he’s known as the father of genetics.
What did Mendel do to prepare for his experiment
He let his pea plants self pollinate
Why were pea plants a good choice?
Each characteristic of me had to possible traits. They produced a large number of offspring. Easy to collect large amounts of data to study. Grew quickly. The study can be completed faster.
Mendel’s first experiment
Mendel cross- pollinated a purebred plant displaying one trait (tall) with a purebred plant displaying the other trait (short)
Genotype: TT x tt
Mendel’s first experiment results
All the offspring were tall even though one of their parents was short
Mendel’s second experiment
Mendel allowed the F1 generation to self pollinate
The offspring were a mixture of tall plants (dominant trait) and short plants (recessive trait) even though both parents(F1 generation) were tall
Mendel’s second experiment results
Mendel got the same results in the F2 generation for each of the seven characteristics: a mixture of the dominant and recessive trait
How did Mendel cross pollinate his plants
He did this by removing the female reproductive parts of one plant and the male reproductive part of the other plant and pollinating the plants by himself
Mendel’s final conclusion
Mendel realized that his results could only be explained if each plant had two sets of instructions ( alleles) for each characteristic
How do you know which trait is the dominant and which is recessive?
The dominant trait shows up more than the recessive trait
Some of the other characteristics and traits Mendel studied
Flower color: purple, white Seed color: yellow, green Seed shape: round, wrinkled Pod color: green, yellow Flower position: along stem, at tip Plant height: tall, short
Why was Mendel’s work not recognized until he died
His results were overlooked and misunderstood at first
Why do we use two letters to represent genotype
One for each allele
Difference between dominant and recessive allele
The dominant allele masks or hides the recessive alleles. Displayed as a capital letter.
The recessive allele is displayed as a lowercase letter.
Gene
The sets of instructions for inherited traits
Each parent gives one allele to its offspring creating a gene for a specific characteristic
Phenotype
An organisms appearance
Genotype
The genetic make up of an organism
The set of two alleles that gives the organism information about a particular characteristic
Homozygous
An organism with two of the same alleles (letters) for a particular trait
Purebred
Heterozygous
An organism with one dominant allele and one recessive allele for a particular trait
Hybrid
Punnet square
A chart that is used to organize crosses
Acquired trait
A characteristic that is the result of experience & influence of your environment
Inherited trait
A characteristic that is genetically passed on from parents to offspring
Codominance
Sometimes one trait is not completely dominant over another. Instead each allele has its own influence (neither trait is dominant or recessive)
The offsprings may be a new color or a mix of the parents colors
Why is their only one possible genotype for an organism that shows the recessive trait
Because the recessive allele is always hidden by the dominant trait, except when the organism receives both recessive alleles from both parents
Why are there two possible genotypes for an organism displaying the dominant trait
The dominant allele always masks the recessive allele.
There is a different genotype for a purebred and hybrid organism
