Category Archives: Miesfeld Biochemistry

Binding of glucose to hexokinase causes a conformational change in the enzyme. This is an example of the __________ model of enzyme catalysis.

Using the delta Gº’ values for the reactions shown below, what is the delta Gº’ value for the conversion of phosphoenolpyruvate (PEP) to 3-phosphoglycerate (3PGA) by the enzymes enolase and phosphoglycerate mutase in the gluconeogenic pathway?

The amino acid sequence of a protein determines its structure. Which of the following statements is true?

Signaling activity of G proteins is controlled by GTPase activating proteins (GAPs) and Guanine exchange factors (GEFs). What are the mechanisms by which GAPs and GEFs control G proteins?

Below is the molecular structure of a single bovine beta-arrestin subunit. Two locations are indicated. What is most likely to interact with the protein at these locations?

Phenylketonuria (1) / Albinism (2) is characterized by white skin due to a defect in the enzyme tyrosinase, which leads to a block in the pathway needed to synthesize adrenaline (3) / melanin (4).  Animals with this condition have an increased risk of skin cancer (5) / mental illness (6). The genetic disease albinism (7)Continue reading “MCAT Style Quiz Question 8.3”

The initial velocity of an enzyme-catalyzed reaction is followed at various substrate concentrations. At very high substrate concentrations it is observed that the initial velocity no longer increases as more substrate is added. The velocity under these conditions is known as ____________.

Biological membranes partition aqueous environments to permit life processes to maintain regions of low entropy within the high entropy state of the surrounding environment. What key chemical characteristic do the major biomolecules in membranes have that allows for the formation of hydrophobic barriers separating aqueous environments?

An infant who obtains nourishment from milk and who has galactosemia is unable to convert____________.