General Biology 2; Unit 5 - Mendelian Genetics

(02-14-2026)

Gene

is a unit of heredity found on DNA that controls a specific trait of an organism.

Allele

is an alternative form of a gene. Each gene has two of it, one inherited from each parent.

Dominant

is an allele that expresses its trait even when only one copy is present.

Recessive

is an allele that is expressed only when both alleles are

Genotype

Refers to the genetic makeup of an organism or the combination of alleles it possesses.

Phenotype

Is the observable physical characteristic of an organism, which results from the interaction of genotype and environment.

Homozygous Dominant

When 2 Dominant Alleles are present… what is it called?

Homozygous recessive

When 2 Recessive Alleles are present… what is it called?

Heterozygous

When both Recessive and dominant Alleles are present… what is it called?

Law of Segregation

Each organism has two alleles for a trait, but these alleles separate during gamete formation (egg or sperm), so each gamete carries only one allele.

Law of Independent Assortment

Alleles of different genes are inherited independently of one another if they are located on different chromosomes

Law of Dominance

Dominant allele masks recessive alleles

Step 1: Parents Have Alleles for a Trait

Step 2: Alleles Separate During Gamete Formation

Step 3: Fertilization Combines Alleles

Step 4: Punnett Square Predicts Offspring Traits

Step 5: Interpret the Results

How traits are passed from parents to offsrping?