In Normal Animals and An, the Rate-Limiting Step in the Biosynthesis

question 120

Multiple Choice

In normal animals and an, the rate-limiting step in the biosynthesis of the catecholamine neurotransmitters dopamine and norepinephrine is

• A) the transport of L-tyrosine across the blood brain barrier.
• B) the decarboxylation of dihydroxyphenylalanine by DOPA decarboxylase.
• C) the 3-0-methylation of the catechol nucleus by catechol-0-methyl transferase.
• D) the hydroxylation of L-tyrosine by tyrosine hydroxylase.
• E) the action of monoamine oxidase on the beta-phenethylamine nucleus.

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Definitions:

Gene-Environment Correlations

A concept in genetics explaining how an individual's genes influence the environment to which they are exposed, leading to various developmental outcomes.

Phenotype

The observable characteristics or traits of an organism, such as its morphology, behavior, and biochemical properties, which result from the interaction of its genotype with the environment.

Dominant Traits

Dominant traits are genetic characteristics that are expressed in an organism even when only one copy of the gene responsible for the trait is present.

Recessive Traits

Genetic traits that require two copies of a recessive allele for the trait to be expressed in an organism's phenotype.