Explain Mendel's Laws of Heredity Flashcards
Laws of Heredity refer to:
Principles regarding how traits are passed on to offspring
One of Mendel’s observations was that there are differences in the prevalence of trains which means:
Some traits are more likely to be passed on than others
Mendel hypothesized that offspring inherit ___ from their parents
Factors
Today, Factor’s are known as:
Genes
Each Gene for a trait comes in varieties called
Alleles
Recessive Allele is only expressed when:
Both Alleles are recessive
What is Mendel’s Third Law?
The Law of Dominance
What is the Law of Dominance?
When both Allele’s are recessive
Offspring inherit ___ copies of each Gene
Two
There are ___ Alleles for each Gene
Two
Combination of two Alleles is called a:
Genotype
If the Chromosome contains two Alleles that are the same, that Genotype is called:
Homozygous
If the Chromosome contains two different Alleles, that Genotype is called:
Heterozygous
The Alleles that are present in an organism determine the ___ of the organism
Phenotype
What is Phenotype?
The expression of the genes for that trait. Phenotypes are physical traits such as color or unseen traits such as blood type
Offspring express either a Dominant or Recessive Phenotype based on:
The two Alleles inherited for a trait
Passed from parent to offspring through Gametes (egg or sperm):
Inherited Traits
Each Gamete carries ___ Chromosome if the Chromosome pair and only ___ copy of each Gene
One, One
Culturally influenced behavior is or is not considered inherited?
NOT
Mendel’s Law of Heredity focus’s on ___ traits
Inherited
What is one way to predict the likelihood of trains in Offspring?
Punnet Square
What is a Punnet Square?
A chart that can be used to determine the ratios of the Genotypes of offspring from a reproductive cross
To use a Punnet Square, you must know:
The Genotypes of the parents
Genotypes are represented by:
Two letters
Capital letters represents:
Dominant Alleles
Small letters represents:
Recessive Alleles
PP means:
Two dominant Alleles
pp means:
Two recessive Alleles
Pp means:
Heterozygous genotype
Mendel’s Law of Segregation states:
Offspring inherit 1 Allele from each parent for a trait, and no Allele is favored or has an advantage over the others
What is a Dihybrid Cross?
The inheritance of two traits using a Punnett Square
A Dihybrid Cross illustrates:
Mendel’s Law of Independent Assortment
A Dihybrid tracks:
The inheritance of two different traits and starts with a parental cross of two true breeding or homozygous organisms
Results hold true only if:
Parental genes for a trait must segregate or separate equally and randomly into haploid gametes (sperm or eggs) that way offspring have an equal chance of inheriting either Allele
In Mendel’s Law of Independent Assortment, one parent is ___ ___ for both traits and the other is ___ ___ for both traits
Homozygous Dominant, Homozygous Recessive
In Mendel’s Law of Independent Assortment, the Offspring (F1) generation are all:
Heterozygous (YyRr) and show only 2 dominant traits
When an F1 cross is formed, the F2 generation shows:
Both dominant and recessive traits, resulting in a ratio of 9:3:3:1
How many Phenotypes will appear in Mendel’s Law of Assortment?
Four, because the Alleles are not inherited together
Non-Mendelian inheritance occurs when:
There are factors other than dominant and recessive Alleles in play
Mendelian ratios occur when:
Simple dominance-recessive relationship exists between two Alleles
What does Non-Mendelian result from?
Factors such as multiple Alleles (ex. blood groups A, B, and O), Incomplete dominance-recessive relationships that lead to an intermediate (ex. red and white alleles making pink flowers), Co-dominance (ex. AB blood groups express both A and B proteins), and Interactions between genes called “epistatis”
If the 3:1 or 9:3:3:1 relationship is not obtained when the F2 Phenotypes are analyzed, it is indicative of:
Non-Mendelian Inheritance
