Unit 6: Genetics

Front

What is a genotype?

Back

The genetic makeup of an organism, represented by the alleles it possesses (e.g., TT, Tt, tt).

Front

What is a phenotype?

Back

The observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences (e.g., red hair, tall stature).

Front

What does heterozygous mean?

Back

Having two different alleles for a specific gene (e.g., Tt).

Front

What does homozygous mean?

Back

Having two identical alleles for a specific gene (e.g., TT or tt).

Front

What is nondisjunction?

Back

An error in cell division that results in an abnormal number of chromosomes, such as trisomy 21 (Down syndrome).

Front

What is a Punnett square?

Back

A diagram used to predict the outcome of a genetic cross by showing the possible combinations of alleles from the parents.

Front

What does the term 'allele' refer to?

Back

Different forms of a gene that can exist at a specific locus on a chromosome (e.g., T and t for height).

Front

What is the significance of the dominant allele?

Back

The allele that expresses its trait even when only one copy is present (e.g., T in Tt).

Front

What is the significance of the recessive allele?

Back

The allele that only expresses its trait when two copies are present (e.g., tt).

Front

What is trisomy?

Back

A genetic condition where an individual has three copies of a chromosome instead of the usual two.