Punnett Squares
What is the punnet square used for?
To determine the outcome of genetic crossings.
Which cell organelle is home to DNA?
The nucleus
Who first studied heredity and the passage of traits from one generation to the next
Gregor Mendel
Inherited vs Acquired
Inherited - Traits passed down genetically from your parents
Acquired - Learned or obtained during life
How are traits passed from parent to offspring?
Through genes during reproduction
A black chicken (BB) is crossed with a black chicken (BB). What percentage of offspring will be black?
100%
Where are genes located?
DNA
What is heredity?
The passage of genetic instructions (traits) from parent to offspring.
Dominant vs. Recessive
Dominant - Represented by a capital letter, will be expressed in a hybrid
Recessive- Represented by a lower case, needs two copies to be expressed
Name two traits that could be inherited from a parent?
Examples: hair color, eye color, height, skin color, freckles, etc...
What is the punnet square used for?
To determine the outcome of genetic crossings.
What do we call the genetic make up of the individual, represented by a set of letters?
Genotype
What type of organism did Gregor Mendel use to first study heredity?
Pea Plants
Genotype vs. Phenotype
Genotype- The genetic makeup of an individual
Phenotype- The physical trait expressed in an individual
How many parents are involved in asexual reproduction?
One
Long ears are dominant (E) in rabbits. If one parent is homozygous dominant for the long ear trait and the other homozygours reccessive (e), what is the only possible genotype of the offspring?
Ee
Inherited traits that children get from their parents come from-
Genes
How many chromomsomes do humans have?
46 or 23 pair
Gene vs. Allele
Gene- Trait (Eye color)
Allele- Version of trait (Blue or Brown)
Two dark brown rabbits have four offspring. Three of the offspring are dark and one is white. What does this tell you about the parents' genes for fur color?
Dark brown is dominant and white fur is recessive. Both parents are heterozygous.
Having dimples is dominant (D). Not having dimples is recessive. (d) Both parents are heterozygous for the dominant trait. What percentage of the children will NOT have dimples?
25%
What are the threadlike structures of DNA that carry genes called?
Chromosomes
The physical trait observed in an offspring is known as it's
Phenotype
Hybrid vs. Purebred
Hybrid- A copy of a dominant and recessive allele (Aa)
Purebred- Two copies of the same allele (AA or aa)
Why does a Punnet Square use capital and lowercase letters?
Capital = Dominant Trait Lower Case = Recessive Trait