3.2.1 Genetic Terms

• The combination of alleles an organism possesses for a specific gene or trait is called its genotype
• An allele is one of the different forms of a gene that can exist at a particular genetic locus (position on a chromosome).locus
• Match the factor affecting phenotype with its description:

  Genotype ↔️ Combination of alleles inherited

  Environmental factors ↔️ Temperature, nutrition, sunlight
• A dominant allele expresses its trait even when paired with a recessive allele.
• The combination of alleles an organism inherits determines its genotype.
• Key factors affecting phenotype include genotype and environmental factors.
• An organism is heterozygous for a gene when it has two different alleles at the same locus.
• If 'A' is a dominant allele for black fur and 'a' is a recessive allele for brown fur, an individual with a genotype of 'Aa' will have black fur
• A recessive allele is expressed only if two copies
• A plant with alleles GG for green color has a genotype of GG


  True
• What does it mean for an organism to be homozygous for a gene?

  It has two identical alleles
• A heterozygous individual with genotype Aa will express the dominant trait if A is dominant over a


  True
• What is a homozygous dominant genotype?

  Two identical dominant alleles
• A homozygous recessive genotype occurs when an individual has two identical recessive
• A homozygous recessive genotype is characterized by two identical recessive
• A heterozygous genotype occurs when an organism has two different alleles
• The phenotype of an organism is influenced by its genotype and environmental
• The Law of Segregation states that during gamete formation, each allele pair separates
• The Law of Segregation states that during gamete formation, each allele pair separates
• Co-dominant alleles result in a blended phenotype because both alleles are expressed equally.


  True
• The phenotype of an organism is its observable characteristics, resulting from the interaction between its genotype and environmental
• A dominant allele requires two copies to express its trait.

  False
• The genotype of an organism is the specific combination of alleles it possesses.
• An organism is homozygous for a gene if it has two identical alleles.
• A recessive allele is only expressed in the phenotype if an organism is homozygous for that allele.
• What is an allele?

  A form of a gene
• Match the type of allele with its description:

  Dominant ↔️ Expressed when one copy is present

  Recessive ↔️ Expressed only when two copies are present

  Co-dominant ↔️ Both alleles are expressed equally
• The phenotype of an organism results from the interaction between its genotype and environmental factors
• In a homozygous dominant condition, the dominant trait is fully expressed
• A dominant allele expresses its trait even when paired with a recessive allele
• In a homozygous dominant genotype, the dominant trait is fully expressed
• Homozygous dominant genotypes express the recessive trait.

  False
• An individual with the genotype bb, where 'b' is the recessive allele for blue eyes, will have blue eyes.


  True
• A heterozygous genotype expresses the dominant allele's trait or a blend of traits.

  True
• What is a Punnett Square used for in genetics?

  Predict offspring genotypes
• What happens to the recessive allele in a heterozygote according to the Law of Dominance?

  It is masked
• If both parents have the genotype Aa, the offspring will have a 50% chance of being heterozygous.

  True
• A dominant allele expresses its trait even when paired with a recessive
• Match the type of allele with its expression requirement:

  Dominant ↔️ One copy

  Recessive ↔️ Two copies

  Co-dominant ↔️ Both alleles equally
• The phenotype of an organism is solely determined by its genotype.

  False