A clinical test sometimes used to diagnose folate deficiency or B12 deficiency is a histidine tolerance test, where one injects a large dose of histidine into the bloodstream and then carries out a series of biochemical determinations. What histidine metabolite would you expect to accumulate in a folate- or B12-deficient patient, and why?

Suppose you discover that bacteria that express OmpF have concentrations of <0.1uM of ciprofloxacin in the cytosol but those without this substance have concentrations of up to 50uM in the cytosol by the time they die.  What does this tell you about the function of the isolated substance, OmpF, which you suspected from the start was related to quinolone resistance?  How is the OmpF structure optimized for this function? Which amino acids in OmpF are suited to each aspect of its function? The structure of ciprofloxacin is shown below for reference.

A cell with an internal concentration of 0.03 molar glucose is placed in a test tube containing 0.02 molar glucose solution.  Assuming that glucose is not actively transported into the cell, describe the internal concentration of the cell relative to its environment?

Which of the following would result in an increase in the amount of F-2,6-BP? (select all that apply) Group of answer choices high blood glucose activation of fructose bisphosphatase 2 increased phosphofructokinase 2 activity increased glucagon secretion increased phosphorylation of the bifunctional enzyme

The purified OXA-M290 enzyme can now be tested to determine which β-lactamase inhibitor is most effective. This inhibitor could be prescribed in combination with a β-lactam antibiotic to treat the infection caused by the E. coli KGH1 strain. Before testing inhibitors against OXA-M290, the kinetic activity of this enzyme must first be measured. The activity of OXA-M290 is measured using nitrocefin, a chromogenic β-lactam antibiotic. When nitrocefin is hydrolyzed by a β-lactamase, it changes from yellow to red in colour. The nitrocefin hydrolysis product has an extinction coefficient of 20,500 M-1 cm-1 at 486 nm. The hydrolysis of 60 μM nitrocefin by 1 nM OXA-M290 is monitored using a microplate reader. The absorbance of the wells in the plate is measured at 486 nm every 30 seconds. This experiment is carried out with three replicates, generating the following data: Time (min) Absorbance of Replicate 1 Absorbance of Replicate 2 Absorbance of Replicate 3 0.5 0.0984…

Why is derivatization (i.e., transesterification) of triglycerides or lipids to fatty acid methyl esters needed for the GC/MS experiment?

In the following scenarios, glucose is absent. Judging these systems as a whole, decide if B-galactosidase and permease are constitutive (always), unable (never), or inducible for each situation. Note, you must use the words inducible, unable, or constitutive. You should only have one answer per block. Please format your answer as a table and upload as a pdf or doc file B-galactosidase Permease |A) I POZYA I PΟΖΥΤΑ" B-galactosidase Permease B) IS ΡΟΖΥΤΑ I POCZYA B-galactosidase Permease С) I POZ'YA ΓΡΟΖΥΑ B-galactosidase Permease D) I PO̟ZYA ΡΟΖΥΤΑ B-galactosidase Permease E) I PΟΖΥΑ I POZ'YA

Peroxidase is an enzyme found in many organisms, from plant to humans. The function of peroxidase is to break down hydrogen peroxide, which is a toxin produced as a byproduct when oxygen is produced during respiration. Myeloperoxidase is a protein found in neutrophils and catalyzes lipid peroxidation involved in immune defense. The overproduction of myeloperoxidase has been found to function as a mediator for tissue damage in inflammatory diseases. (8 points) a. Identify two examples of environmental factors that may impact myeloperoxidase activity. Describe how each of the environmental factors would affect the reaction rate of the enzyme. b. Predict the how researchers can use myeloperoxidase activity as oxidative stress biomarkers in patients with rheumatoid arthritis. Provide reasoning to justify your prediction.

Resistance to many penicillins is the result of cell wall mutations in a variety of bacteria. True or false?

Patients with a form of early-onset diabetes were found to carry a variety of mutations reducing the function of the glucokinase (GK) enzyme. These patients are heterozygous for one of the mutations, and thus show only partial rather than complete loss of GK activity. Answer the following questions about these patients. 1. How would blood sugar levels likely be affected in GK-mutation patients? Briefly explain your choice (25 words or less) a. Higher than normal b. Normal C. Lower than normal d. Cannot predict based on the provided information