Repeated USMLE Questions Step 1- 265



As physicians, we need to know some definitions in Genetics, which are related directly to our practice and guide us to diagnose and treat many genetic disorders. These items include genome, genotype, phenotype, genetic code, gene expression, etc.

Which one of the following choices describes the definition of a phenotype?

A- Genetic constitution of an organism

B- DNA structure that determines the expression of a trait

C- An observable physical or biochemical trait on an organism

D- Physical location of a trait on a DNA molecule



Answer

Phenotype is the observable physical or biochemical features that seen on an organism featuring the expression of genotype. Genetic constitution of an organism is genotype while the DNA structure that determines the expression of a trait is known as gene expression. Genetic code is the physical location of a trait on a DNA molecule that carries genetic information of the living cell. It is the nucleotide triplet of DNA and RNA molecules.

The correct answer is C



11 thoughts on “Repeated USMLE Questions Step 1- 265”

Leave a Comment